US 2305785 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Dec. 22, 1942. G. JENDRAssIK 2,305,785
WORKING PROCESS AND MECHANICAL EQUIPMENT FOR GAS TURBINES Filed May 18, 1958 5 Sheets-Sheet l Illnlflllllll llllIIlIl/f.
M/inesses da bf G. JENDRASSI K Dec. 22, 1942.
WORKING PRocEss AND MECHANICAL EQUIPMENT FOR GAS TURBINEs Fil-.ed May 18, 1958 5 SheetS-SheeI 2 lll "4 Purifier In ven for ffy. 2.
WORKING PROCESS AND MECHANICAL EQUIPMENT FOR GAS TURBINES Filed May 18, 1938 5 Sheets-Sheet 5 F 6 .l 3 m P 0 .0. kw wl l l l Il hl/ln Il 7 l |l|. Iv l-) y 7 f 0 l. /T f w... U 9 o 7 m .01. o 5 P v u n; 0V 2,5 e M o 9. .n /N 6 W 9 T r\ n alu r M ao 5 .al na w f.
Dec. 22, 1942. G. JENDRAssIK 2,305,785
WORKING PROCESS AND MECHANICAL EQUIPMENT lFOR GAS TURBINES Filed May 1B, 1958- 5 Sheets-Sheet 4 Compressor Fig. 4. W/'nesycs ff) ven for:
Dec. 22, 1942.
G. JENDRASSIK WORKING PROCESS AND MECHANICAL EQUIPMENT FOR GAS 'IURBINES Filed May 18, 1958 5 Sheets-Sheet 5 Turbine Compresor f 4 HemL Exchanger Fig.
Patented Dec. 22, 1942 WVORKING PROCESS AND MECHANICAL EQUIPMENT FOR GAS TURBINES George Jendrassik, Budapest, Hungary; vested in the Alien Property Custodian Application May 1s, 193s, serial No. zos,556-
` In Hungary May 18, 1937 4 Claims.
According to the known gas turbine proposals it is before the passage of the working medium through the gas turbine, i. e. before the expansion of the working medium has taken place, that the combustion of the fuel in the Working medium is eifected, in order to enable the heat generated by the combustion of the fuel to be converted into mechanical work with an as high efciency as possible. This method possesses many drawbacks. The working process and the gas turbine suitable for carrying the said process into effect, which are forming the subj ect-matter of the present invention, eliminate these drawbacks by an arrangement according to which the'combustion of at least a part of the fuel to be burnt in the working medium of the turbine is effected after the said working medium has passed through the turbine. This working process can be employed for multi-stage gas turbines of a type fitted with a heat exchange device composed of metal sheets in which latter the heating of the working medium, which has been compressed prior to such heating, is effected by means of the heat contained in the working medium leaving the turbine in an as eflicient degree as possible before the admission of the said Working medium into the turbine. If in such turbines fitted with heat exchange device of the said type the fuel is-at least partly-burnt inthe working medium after the latter has passed through the turbine, but
before the working medium has entered the heat exchange device, it is indeed only the spent gases leaving the turbine that will be heated by the heat produced by the combustion, but the said heat exchange device, which should preferably operate according to the counter-current principle, will enable this heat to be transferred to the working medium of higher pressure entering the turbine, this being done, notably, theoretically, without any particular losses deriving from the new arrangement, in view of the fact that the transmission in its total extent in the heat exchange device of the extra quantity of heat introduced into the working process behind the turbine but in front of the heat exchange device canl be assured by designing and dimensioning the heat exchange device in a suitable manner. Accordingly this heat will not be lost, but is able to perform work, without there being any necessity for products of combustion flowing in the turbine.
This process, or in other words, the gas turbine operating in this manner, offers substantial advantages as compared to the processes known up to now, as it renders possible the use of fuels of such a kind also, the gases of combustion, ash etc. of which are exerting a detrimental influence on the parts of the turbine, and further it enables the combustion to be eected in the working medium leaving the turbine i. e. in a working medium of lower pressure-which is usually equal to atmospheric pressure-by means of firing equipments of a simple kind, enabling also fuels of a primitive, inexpensive kind, like low grade,
coals, etc. to be burnt in an eiicient manner.
It is a further advantage of this process, that in cases, where it is desired for the purpose of ensuring higher eiiciency or the performance of a higher amount of work, or for other reasons, to produce, if possible, an isothermc expansion or an expansion during the course of which the introduction of heat into the working medium is continued in the turbine itself, it will be permissible, without any substantial loss to effect the combustion of the f uel partly also after the passage of the working medium through the turbine, whereby the carrying intoV effect of the ideal expansion at a constant temperature will be substantially facilitated. Finally, this process will enable the realization of expansion accompanied by the introduction of heat mentioned above to be carried out also in the cases of such fuels as are not directly suitable for producing such a combustion, or the gases of combustion of which are, owing to their detrimental effects, unsuitable for passing them through the turbine. Notably this is rendered possible by the said working process, owing to the fact that the combustion of such fuels is effected partly after they have passed through the turbine, a part of the fuel being, during such combustion, converted either by means of distillation, or by chemical changes, gasification, cracking etc. into a kind of yfuel which can be burnt without any difficulty or drawback either in front of the turbine or during its passage through a part or the whole of the turbine, or between the various stages of the latter.
Among the figures of the annexed drawings, Fig. 1 illustrates, in a diagrammatical manner, the arrangement of the turbine and of the whole equipment serving as an example for carrying the working process into eiect, with a furnace arranged behind the turbine and with a heat exchange device operating in a continuous manner. Fig. 2 is a diagrammatical drawing of a further embodiment shown by way of example, suitable for the use of solid fuels and with combustion effected partly behind the turbine. Fig. 3 is a diagrammatical drawing of another embodiment shown by way of example suitable for the use of solid fuels likewise, in which the partial combustion of the fuel in front of the turbine is effected in such a manner that the portions becoming gasied etc. of the said fuel are partly being burnt behind the turbine. Fig. 4 is the diagrammatical cross-section of an embodiment shown by way of example in which a heat exchange device .operating in a non-continuous manner is employed. Finally Figs. 5 and 6 are illustrating advantageous variants of the arrangement according to Fig. 1.
In Fig. 1, the rotor 2 of the rotary compressor I, shown by way of example as being of the axial throughilow type, is driven by means of the shaft coupling 3 by the rotor 5Y of the turbine I shown likewise as being of the axial throughflow type, the other shaft end of the said rotor 5 joining on by means of the shaft coupling 6 to the consumer of mechanical energy. 'I'he working medium-preferably airenters the compressor through the inlet opening 'I and leaves it through the discharge opening 8. It is between this discharge opening and the inlet opening '9 of the turbine l that the heat exchange device I is arranged, which in the.
case of this example of construction is of continuous operation and of the counter-flow type. To the discharge opening of the turbine there join on, on the one hand the by-pass pipe line I3 capable of being controlled by means of the throttle-valve I2. and on the other hand the pipe line I capable of being controlled by means of the throttle-valve I4. The pipe line I5, moreover, possesses a branch Il capable of being controlled by means of the throttle-valve I8, which branch issues into the space I9 of the flu'nace I8, suitable, for example, for the combustion of solid fuel. In the example shown, it is below the grate 20 of the furnace equipment I8 that the pipe-line I5 is joining on. Behind the furnace equipment, the by-pass pipe-line I3 and the flue gas duct 2| of the furnace equipment are, after their mutual junction, joining on to the heat exchange device I II, into which the gas enters through its inlet duct 22. The gas leaving the heat exchange device is discharged through the duct 23 into which the fan 25 driven by the electric motor 24 is installed. It is the pit space 21 of the furnace equipment I8 which contains the solid fuel, which is admitted by the charging valve 28 and through the door 29.
'I'he method of operation of this apparatus is the following:
'I'he working medium enters the compressor driven by the turbine through the inlet opening 1 of the compressor I, and leaves it through the discharge duct 8 at a pressure higher than the .admission pressure, e. g. at a pressure amounting to 1.5 to 8 times the admission pressure. Following this, the working medium passes through the heat exchange device I0 designed on the counter-now principle in which its temperature becomes raised considerably, e. g. to a temperature of 450-900 C., at the expense of the heat of the spent gases leaving the turbine plant, that is to say the furnace, and following this it enters through the inlet opening 9 into the turbine 4. Here its pressure drops during expansion to approximately the figure of the admission pressure of the compressor, and during such expanson it performs mechanical work. From the turbine the gas discharged at the discharge opening passes through the duct I5 or the by-pass duct I3, respectively,
partly into thefurnace I8 75 turbine through the duct and partly directly;` into the duct 2| leading to the heat exchange device. The gas entering the furnace causes combustion to be eii'ected, becomes heated and-if necessary-the combustion is continued in the space I8, use being made for this purpose of the secondary admixture air received through the duct Il. Following this the products of combustion of' high temperature, leaving the space I8, are for the purpose of adjusting at will. the temperature of the current of gas heating the heat exchange device, becoming mixed with the Working medium supplied by the by-pass duct I3, and are through the duct 2| entering the heat exchange device I8, through which latter they are passing preferably in counter-flow relatively to the direction of throughilow of the high-pressure medium entering the turbine, and during this passage they are transmitting their heat to the said highpressure working medium in an as complete degree as possible. The fan 25 produces a certain depression in the duct 2| and thereby in the furnace I8, so that when attending to the operation of the furnace, one need not fear that the hot gases should rush out and accordingly the handling of the furnace will be attended without any danger. The control members I2, Il, I5, which may for example be throttle valves, are serving for regulating the air quantities for the mentioned various functions.
ABy means of this example of construction it is possible to carry into eifect that variant of the working process according to the invention in which the fuel is burnt in its totality behind the turbine. In the case of this variant a furnace or combustion chamber is inserted into the path of flow of the working mediumv behind the turbine and in front of the heat exchange device, through which furnace or combustion chamber atleast a part of the working medium passes, the control members mentioned in what precedes, as valves etc. being arranged in the path of travel of the working medium for the purpose of regulating the quantity of working medium flowing through the furnace or combustion chamber.
In the case of the arrangement shown on Fig. 2 combustion is taking place not only behind the turbine, but also in the turbine before expansion and during expansion. In the case of this arrangement it is to the discharge duct 54 of the compressor 53 driven by the turbine 52 that the heat exchange device 55 operating in counteriiow is joining on, and after traversing this heat exchange device the compressed gas enters the 58. From the turbine the gas discharged through the duct 51 passes through the duct 58 into the furnace 5I, which latter is in the example of construction shown suitable for the combustion of solid fuels, in such a manner, that the fuel will partly be burnt and partly will become gasiiied or distilled etc., the said furnace being at the same time also suitable for removing the fuels formed in this manner from the furnace. In the case oi' the example shown the air entering the furnace 5I through the openings 5| is partly flowing in the upward direction, during which flow the combustion of a part of the fuel with the oxygen contained in the air takes place. The gases entering the space 63 from the pit space 52 of the furnace are completely burnt with the secondary air arriving through the duct 64 and are through the duct 65 passing'into the heat exchange device 55, and after having passed through the heat exchange device, they are leaving the latter through il:
discharge duct 66. As far as that part of the working medium the ilow of which takes place in this manner, is concerned, the method ofv operation corresponds to the principle of operation illustrated on Fig. 1. The second part of the working medium, on the other hand, is handled in the case of this example of construction in such a manner as to enable a secondary fuel, capable of being led back into the turbine and burnt in the latter, to be obtained by such han- :lling- This second portion of the working medium saturated with the fresh air entering through the ducts 6| is flowing downwards in the furnace, during which flow it gasiiles a part of the fuel. The combustible gas or vapour of combustible material produced in this manner, is discharged through the duct 61 provided below the grate. The filter or purifier |02 of this duct serves for removing the impurities contained in the gas. lFrom here, the gas passes through the ducts |03 and |05, respectively, into the counter-now heat exchange devices 68 and |05, respectively, provided for this branch of flow, and transmits its heat in the heat exchange device 68 to the compressed gas leaving the compressor. The duct |05 branching out from the delivery duct 54 of the compressor joins on to the admission duct |01 of the heat exchange device |05, Whilst the duct |08 of the heat exchange device is returning the air arriving through the duct |01, after it has been preheated by means of the gas, directly into the current flowing in the duct 56 towards the turbine. If the regulating member provided in the duct |03 is completely closed, the gas arriving through the duct 61 will in its totality ow through the heat exchange device and will there be cooled down to approximately the end temperature of the compressor, following which it will pass at this temperature through the pipe I9 into the heat exchange device 68 connected in series in the direction of the throughflow of the gas with the heat exchange device |05, in which heat exchange device 68 as well as in the purifying and cooling equipment lill connected behind the latter it will become cooled down still further and if necessary also purified. The cooling equipment receives its cooling water through the lpipe line H2 and the cooling water leaves this cooling equipment through the pipe line I3. After having passed through the cooling equipment the gas passes through the duct H4 into the compressor 10 driven by the electric motor 1| in which compressor its pressure .becomes raised to at least the gure of pressure ruling at the point i of the working cycle, i. e. of the turbine 52 at which point it is intended to introduce the gas. After leaving the compressor 10 the gas will during its passage through the counter-flow heat exchange device 68 become heated, following which it will through the junctions 13, 13' branching out from the duct 12 get into the combustion spaces provided in front of the turbine and between the various stages of the turbine, respectively. In the constructional example shown, combustion spaces 48, 49 are provided in front of the turbine andA behind a section of the turbine, respectively, into which spaces the burners 50 and 5|, respectively, for the introduction of fuel are issuing at a number of places.
The spaces of combustion are designed in such a manner that a part of the working medium of the turbine flows into them and the fuel introduced into them will become burnt in the said working medium. The combustion may also be- `the furnace.
come propagated into the turbine and it is even possible that it is only after passage through the turbine that it will be entirely completed, whereby it becomes possible to produce expansion accompanied by the introduction of heat in the turbine. The control valves ||0 and H6, respectively, are intended for regulating such part of the gas leaving the furnace through the duct 61 as flows through the heat exchange device |05, whereas the quantity of compressed air 'flowing through the heat exchange device is regulated by means of the control valve Through the pipe 59 branching off from the pipe 51, and following this through the duct 14 joining on to the said pipe 53, a part of the air enters the jacket 15 of the furnace 60 in order to diminish the losses cf heat in the furnace equipment, following which, after traversing the jacket, it is, through the pipe 16 joining on to the jacket, joining on to the current flowing in the duct 65. To the pipe 51 there joins on the by-pass line 11 in which the quantity of working medium getting into the furnace can be regulated in accordance with the load of the engine, etc., by means of control members as valves, slide valves or the like 18, 19 arranged in the path of the working medium of the turbine. The control valve 80 serves for regulating the quantity of secondary air for admixture, whilst the valve 8| serves for regulating the quantity of gas passing through the jacket of The fuel is introduced into the furnace chamber through the door 82, the valve 83 and the charging pit 84. A circumstance by which the handling of the furnace isvsubstantially facilitated is that there is no pressure above the atmospheric in the furnace, as a suction eect is, produced in the same by the fan 8S driven by means of the electric motor 05 or by any other means.
In order to prevent any excessive heating of the gas passing through the furnace 60 it is advisable to introduce water or steam also into the This purpose is served by the tube coil M1, which in the arrangement shown by way of example is arranged in the duct of the waste gas but can also be arranged elsewhere. Through this heating coil which can also be constructed as a simple heating container, so that its steam space should join on to the pipe line, water is passing, which evaporating in the said container, and passing through duct l I8 becomes admixed to the air entering the furnace. Thus steam will enter the furnace; which steam Will become dissociated in the furnace chamber and will diminish the temperature ruling there. One part of the gas formed can be burnt inthe space 63 in front of the heat exchange device 55, whilst the combustion of its remaining part leaving through the pipe E1 will be effected in the way described above.
It is also possible to operate the equipment described in such a manner that it is not from junction |06 that compressed air for the inlet duct |01 of the heat exchange device |05 abstracting the heat of the combustible gas leaving the furnace is being taken, but that duct |01 is made to join on to duct |20 by means of shutting off the branch |06. In this case it is the air which has already passed through the heat exchange device 55, and which accordingly has become substantially heated that will enter through the duct |20 into the heat 4exchange device |05, in consequence whereof the temperature of the compressed gas entering the heat exchange device 68, and accordingly also that of the compressed gas leaving the heat exchange device 58 will be higher. This method of procedure may be advantageous from the point of view of the combustion of the gas, for which purpose the quantity of compressed air passing through the heat exchange device |05 can be adjusted by means of the control member I 24. It is, however, also possible to regulate the temperature of the combustible gas leaving the heat device 68 through the pipe 12 by means of the control valves I0 and I I6, respectively. The equipment described can also be constructed and operated in such a manner that the duct 65 is completely closed by means of the throttle-valve |I5 or'in some other manner, so that it is only combustible gaseous fuel that is led out from the furnace 60, so that the equipment will operate as a gas generator. In such a case the progress of the cycle of operations will be such that the combustion will become extended fromthe turbine through the ducts 51, 11 partly even into the heat exchange device and will be completed in the latter. In this last-named case it will be particularly advantageous to introduce steam into the zone of combustion as shown e. g. by means of the duct I I8 for the purpose known in connection with gas generators. Such introduction will be justified in an increased degree in the case oi' the apparatus described, because also the fresh air entering the same is at a high temperature oi' about 35o-500 centigrade and thus it will be necessary in a higher degree still to prevent any overheating of the furnace. In case liquid, i. e. a liquid combustible substance should become condensed owing to the cooling down of the gas in the heat exchange devices |05 or 63 from the combustible gases leaving the furnace 60 through the duct 61, the removal of such products can be effected through the pipes |2| and |22 by means of the pump I 23 which may be of any desired type. The fuel obtained in this manner can be introduced into the combustion chambers 43 and 49 respectively mentioned above by means of suitable apparatus and can be burnt in the same.
'I'he example of construction described serves for carrying into eil'ect such a variant of the working process forming the subject of the invention, in which in a furnace arranged behind the turbine, through which at least a part of the working medium passes, a part of the fuel is burnt, whilst from another part of the fuel combustible gases, i. e. gaseous fuel is produced by means of gasification, distillation, cracking etc., and such gaseous fuel is led in front of the turbine, and possibly between the various stages of the turbine, or possibly into separate combustion chambers where combustion takes place. By returning the gaseous fuels thus formed in the furnace by means of distillation, etc. into the turbine in this manner it is possible to carry an expansion accompanied by the introduction of heat into eil'ect in the latter.
In order to ensure that an expansion accompanied by the introduction of heat should take place in the turbine, which is advantageous for many reasons, it is indeed easily possible to ensure by the suitable construction ofthe combustion chambers and by employing a suitable method for the introduction of the fuel, that the combustion of the fuel should be continued also during its throughtlow through the turbine. In view of the fact, however, that throughiiow through the turbine requires only a very short time, about one hundredth of one second, it would cause great difiiculty to regulate the combustion in the turbine in such a manner as to ensure that the combustion 7V should already be completed when the gas leaves the turbine. The process forming the subject of the invention, according to which it is possible to continue the combustion also after the passage of the gas fromthe turbine has been completed. will greatly facilitate the carrying into effect of an expansion accompanied by the introduction of heat.
In the embodiment shown by way of example on Fig. 3 the compressed gas leaving the compressor 88 driven by the turbine l1 through the duct 89 will after having passed through the heat exchange device 90 partly enter in a quantity determined by the control members 9|, l2, through the duct 93, into the furnace I4, wh the fuel will partly become burnt and Partly gasifled, distilled, etc. The gas ilowing to the furnace will partly, after having become heated up by the eIIects of the combustion, pass through the duct and the purifier |25 into the inlet duct 96 of the turbine and partly it will with the combustible products prepared from the fuel, pass through the ducts 91, Il and the purifier |26 to the burners 99, 99'. The expanded gas leaving the turbine will through the duct |00 pass into the inlet opening of the heat exchange device 90 and, following this, it will reach the heat exchange device through the discharge duct IDI. In the case of this variant of construction also, it is advisable to introduce steam into the combustion chamber. This purpose is served by the water tank |21 arranged around the duct 93 and fed through the pipe |29, from the steam chamber of'which tank the steam generated enters the combustion space of the furnace through the pipe |29.
In the case of this arrangement also, it is possible to construct the furnace equipment in such a manner that it should operate as a gas generator only, whilst the gas produced is, for the purpose of producing an expansion accompanied by the introduction of heat, burnt in the turbine or partly behind the turbine. In this case it is necessary to employ in front of the turbine a furnace through which the working medium is passing, in which furnace the fuel is partly burnt and partly subjected to distillation, etc. whilst the combustible gas or gaseous fuel produced will at least in part become burnt either in front of the turbine or during or after its passage through a part of the stages of the turbine, whereas a further part of the gas, i. e. of the gaseous fuel will only become completely burnt after having passed through the turbine, at the last stage in front of the heat exchange device. The purpose of this arrangement is to enable such an expansion to be carried into effect by means of gaseous fuels obtained by gasification, distillation etc. from such kinds direct combustion of which it is not possible to carry the expansion accompanied by introduction of heat into eiIect in the turbine, particularly if this should be done in such a manner that the vcombustionv be continued behind the turbine also.
In the case of the embodiment shown by way of example on Fig. 4 it is between the turbine 30 and the compressor 3| driven by it, i. e. between the discharge duct 32 of the compressor and the inlet opening 33 of the turbine that the heat exchange device 34 operating periodically, and of the counter-flow type likewise, is inserted. In the embodiment shown by way of example this heat exchange device is composed of three units (35, 35', 35"), each of which is tted on the cold side with the controlled inlet members of fuel by means of the 36, 36', 36", and with the controlled outlet members 31, 31', 31". The heat exchange device is on the hot side likewise iitted with controlled inlet and outlet members, viz. with the inlet members 39, 39', 39" and with the outlet members 38, 38', 38". In the example of -construction shown these members (valves) are controlledby the cams 40 mounted on the camshafts 4l-4l'. The camshafts are driven by the electric motor 42 partly in a direct manner and partly through the transmission gear 43.
In the interior of the various units of the heat exchange device metal plates, preferably arranged in parallel with the direction of the throughflow, are provided, the mutual distance of which is, in view of increasing the heat transmission, made as small as possible (0.1-5 mm., preferably less than 2 mm.), whilst perpendicularly to the direction of the throughflow they are divided by means of air gaps into individual bundles of plates, so as to prevent as far as possible any conduction of heat taking place from one end (the hot end) of the heat exchange device to its other (cold) end. It is instead of metal plates, however, also possible to employ by way of heat-storing material metal wire mesh or some other lining of great surface area consisting of metal or other material, for instance gravel, and incorporating air spaces. The inlet duct 32' communicating with the antechamber of the inlet valves 36, 36', 36" serves for the introduction of the compressed fresh working medium into the heat exchange device. On the hot end the gas leaves the heat exchange device through the duct 44 communicating with the antechamber of the discharge valves 38, 38', 38". To the outlet duct 45 of the turbine there joins on the duct 46 through which the hot gas leaving the turbine passes into the antechamber of the inlet valves 39, 39', 39" of the heat exchange device. The spent and cooled-down gas leaves the heat exchange device through the heat exchange units 35, 35', 35" and through the duct 41 communicating with the antechamber of the discharge valves 31, 31', 31". In the example of construction shown the combustion chambers I3I, |32, are arranged in front of or between the stages of the turbine, the fuel introduction burners, atomizersetc. 13, or 13' respectively issuing in several plates into these chambers. The method of operation of this apparatus is the following:
The compressor draws in the gas-e. g. airthrough its inlet opening 52 and after compression delivers it through the ducts 32, 32' into that section of the periodically operating heat exchange device the inlet valve 36 of which happens to be open at the moment. During this time the discharge valve 38 of the heat exchange unit in question is open likewise, so that the gas will iiow through the heat exchange unit in the direction of the arrow I and will enter the turbine through the inlet opening 33. During its passage through the regenerator the compressed gas will become heated. The gas leaving the turbine passes through the ducts 46 and the inlet valve 39 happening to be open at the moment into the working chamber of the regenerator and leaves through the discharge valve 31 open simultaneously with the inlet Valve referred to above and through the discharge duct 41. Following this the gas iiows in the direction of the arrow II through the heatV exchange device and becomes cooled down during such throughflow. The heat odically by means of the control valves in such a manner as to ensure that throughflow through them should take place alternately in the direction of arrow I or in that of arrow II in such a. manner that whilst in a part of the units the flow takes place in the direction I, the flow Vin the other group of th units should take place in the direction II.
By constructing the heat exchange device in a suitable manner, it is possible to heat up the compressed gas entering the turbine by means of the heat of the expanded gas leaving the turbine to approximately the temperature of the last-named gas. The compressed gas entering the turbine through the inlet duct 33 will during its passage through the turbine perform work owing to its expansion.
By means of thecombustion chamber I3l, i. e. of the atomizers or burners 13 it is possible to introduce fuel into the gas before the latter enters the turbine, that is to say to introduce heat into the gas before its expansion, or in case of the suitable control of the combustion also during the expansion. After the gas has iiown through a part of the turbine, the introduction of further quantities of fuel, i. e. of heat can be effected by means of the atomizers or burners 13'4 arranged in the combustion space |32. In any case however the adjustment of the combustion will be such that when the gas leaves the turbine, the combustion should not be completed yet, but should also extend into the antechamber of the valves 39. Naturally, however, there is also nothing to prevent the heat exchange device of periodical operation employed in the last example to be also employed according to the arrangements described in the previous examples.
It isvery essential in connection with the types of apparatus described that the heat exchange device, no matter whether it is of periodical or of continuous operation, should operate in a perfect manner with a low amount of loss,I as it is only in this case that it will be possible to transfer the heat introduced behind the turbine to a fresh supply of working medium of higher pressure without appreciable loss in eiciency. For
exchange umts are mutually connected perithis purpose the heat exchange device of the counter-flow type and operating in a continuous manner described in connection with the former examples is particularly suitable, provided that the mutual distance ofthe plates separating the working spaces of the heat transmitting and of the heat receiving media from each other is small (less than 5 mm.). Should in accordance with the last-named example a heat exchange device operating periodically be employed, it on the one hand for the reason mentioned, and on the other hand in order to enable the so-called charging losses arising at the changing-over of the heat exchange units to be reduced to a important, likewise, that the mutual distance of the plates should be very small, notably, as mentioned, less than 5 mm. likewise. In order to minimize the quantity of heat flowing from the hot end of the heat exchange device towards its cold end, it is preferable to fit such a heat exchange device withat least ve air gaps, perpendicular to the direction ofthe flow.
`In the case of all the variants of process and apparatus described in what precedes it is an important and characteristic feature that at the moment when the combustion starts it is only with a part of the working fluid flowing through the apparatus that the fuel is brought into contact. This appears in the case of the arrangeseparated or detached of a part of the working fluid being passed through a duct by-passing the furnace equipment, w in the case of the arrangement according to 4, it appears from the circumstance that the fuel is introduced into the combustion chanlbers ill, |32, into which there enters at the same time, for the purpose of maintaining the combustion, also a part of the working uid flowing in the working space of the turbine, whereas the remaining part of the working fluid flows along in front of the junction openings of these combustion chambers. This portion of the working fluid Joins on to the remaining part of the working fluid after having left the furnace equipment or the combustion chamber, thus becoming mixed with this last-named portion. 'Ihis will enable the high temperature ruling in the combustion chamber to be reduced, thereby reducing also the danger of any damage being suffered by those parts of the apparatus which are sensitive towards high temperatures as e. g. the plates of the heat exchanger or the blades of the turbine, and thus offering the possibility of constructing these constructional parts of normal constructional materials also which are not particularly heat-resisting and are therefore not expensive. Moreover, however, the fact of eifecting the combustion of the fuel in such a manner possesses special importance also for the reason because in case of the employment of solid fuel the quantity of fuel to be burnt for the purpose of the introduction of heat can in case of the variation of the load be controlled by merely controlling the quantity of air passed through the quantity of fuel accumulated in the furnace, so .that in accordance with varying loads, varying quantities of air have to be passed through the furnace equipment; in view of the fact that the quantity of air the compressor of the equipment is able to supply is dened from other considerations, this can only be achieved if, in the manner described above, only a part of the total current of working uid is passed through the furnace equipment, whereas the other part of the current of working fluid should be guided so as to by-pass the furnace equipment and should be admixed to the products of combustion leaving the furnace equipment. In order to enable the output to be controlled, it is, of course, necessary that it should be possible to control the quantity of air led into the furnace equipment and that led through the duct by-passing the furnace equipment, respectively, such control being effected preferably by means of control members, e. g. throttling valves mounted into the corresponding duct branches.
The arrangements described can be employed in any desired combinations and also in variants diering from the types of design described above by way of example only.` Thus for instance it is possible (similarly to the heat exchange devices shown in Fig. 2) to employ in the main gas flow circuit also a plurality of heat exchange devices connected in parallel or in series, through which possibly not even the whole quantity of gas or air passes. This last-named arrangement 2,305,785 l :ments according to Figures 1 to 3, from the fact respectively, of two heat exchange devices situated in the main gas flow circuit, is illustrated in an arrangement, shown by way of example, for each of these two alternatives by Figs. 5 and 6, respectively, which are developed from Fig. 1 and accordingly the symbols used for their common constituent parts are identical with those employed on this last-named ligure. According to Fig. 5, the gas to be heated leaving the compressor I as well as the expanded gas to be cooled down leaving the turbine l' are led, divided as to their quantities, thrpugh the heat exchange devices il and Il', respectively, notably through the heat exchange device Il by means of the admission ducts arranged as shown on Fig. l and through the heat exchange degice Il' by leans of the pipe lines l and l branched o! fr?. the outlet opening l of the compressor and from the admission junction 9 of the turbine, respectively. The expanded gas leaving the heat exchange device lll after having surrendered its contents of heat, is passing through the opening 2l directly into the atmosphere, whereas the heat exchange device I0' is, as far as the path of ilow of the expanded gas is concerned, connected with the gas generator Il in a manner similar to the arrangement of the heat exchange device Il of Fig. 1, and accordingly the suction fan 2l is mounted into its outlet opening 23'. As against this arrangement of the heat exchange devices in parallel connection, Fig. 6 shows arrangement of heat exchange devices in series connection. In this arrangement a part of the quantity of compressed gas flowing through the heat ex.
change device I Il is led through the heat exchange device I0" also, following which it is united with the quantity of gas following through the heat exchange device ill exclusively and is led to the inlet opening of the turbine, whereas as regards the quantity of gas leaving the turbine l, one part of the same is led through the heat exchange device Il only, whilst the remaining part is, after flowing partly through the gas generator i8 in accordance with the arrangement of Fig. 1, first led through the heat exchange device Ill" and following this-joining on to the quantity of expanded gas flowing to the heat exchange device I0 only-is led through this latter heat exchange device also. The fan 25 producing the depression required for the generation of gas is in this case also mounted into the discharge duct of the heat exchange device il" directly cony nected with the gas generator il.
may be advantageous for instance in'connection Awith the transfer of the heat of the gases of high temperature obtained in the furnace on the fresh compressed working medium before mixing the gas of high temperature with gas of lower temperature.
Such a connection in parallel, or invseries,
By such a grouping of the heat exchange devices it is possible to ensure that only one of them, notably the one which stands in direct connection with the gas generator i8 (the heat exchange device lli' or III", respectively) is exposed in a greater degree to the deposit of soot from the products of combustion and in consequence hereof it is advisable to provide for a suitable possibility of cleaning of this last-named heat exchange device. (The heat exchange de vice Il according to Fig. 5 is not exposed to the eifects of products of combustion at all.) In the arrangement according to 6 the heat exchange device i0 is at a low temperature, whilst the heat exchange device Il" is at a high temperature; through the latter a smaller quantity of gas is passing owing to the arrangement illustrated, than through the heat exchange device ill and the temperature drop also is smaller in it than in the heat exchange device Il. As against this, in the arrangement according to Fig. the relative magnitude of the quantities of gas flowing through the heat exchange devices I0 and I0' depends on the adjustment of the open cross-section of the passage valves inserted into the gas ducts, and the lowest temperature of the two heat exchange devices will be identical, whilst their highest temperature is of smaller magnitude in the heat exchange device I0 and .of larger magnitude in the heat exchange device l0'. i
Naturally it is also possible to employ compressors of a design modified in some respects.
Thus for instance it is, owing to its high eiliciency, particularly advantageous to employ a compressor, per se known, in which the eects of friction on the flow-guiding wall surfaces of the stator or of the rotor are eliminated by returning thespent boundary layer adhering to the wall surface into zones of lower pressure. Such a compressor is shown on Fig. 1 in which in the stator 2 the spent boundary layer i's in consequence of the prevailing pressure difference between the openings of each of the return ducts |33, |34 in the stator, removed and led back through the said ducts in front of stages of lower pressure, where it enters again into the working space and owing to the pressure drop available again acquires a suitable velocity. It is in a similar manner that the removal of the boundary layer is effected, by means of similar return ducts shown on the drawings, in the rotor also.
1. A process for generating mechanical power by means of an arrangement containing a rotary compressor, a multi-stage gas turbine and a heat exchange device composed of metal sheets, consisting in introducing heat into the gaseous working medium of the process for the conversion into mechanical work by means of a part of the fuel to be burnt being completely burnt in the working medium after its having expanded in the' turbine, in bringing initially only a preferably adjustable part of the working medium into contact with the fuel for effecting this combustion, in mixing such part of the working medium, after at least a part of the fue1 being brought into contact therewith has been burnt therein, to the lremaining part of the working medium so as to form a common flow, in leading the ow of working medium containing practically all the heat imparted to it in the course of the said complete combustion, into the heat exchange device, and in transmitting the available part of the said quantity of heat in the said heat exchange device to the previously compressed fresh working medium before its entering the turbine, another part of the fuel being burnt in the working medium before the completion of its expansion in the turbine.
2. A process for generating mechanical power by means of an arrangement containing a rotary compressor, a multi-stage gas turbine and a heat exchange device composed of metal sheets, consisting in introducing heat into the gaseous working medium of the process for the conversion into mechanical work by means of a part of the fuel to be burnt being completely burnt in the working medium after its having expanded in the turbine, in bringing initially only a preferably adjustable part of the working medium into contact with the fuel for effecting this'combustion, in mixing such part of the working medium, after at least a part of the fuel being brought into contact therewith has been burnt therein, to the remaining part of the working medium so as to 75 form a common flow, in leading the flow of working medium containing practically all the heat imparted to it in the course of the said complete combustion, into the heat exchange device, and
l in transmitting the available part of the said quantity of heat in the said heat exchange device to the previously compressed fresh working medium before its entering the turbine, another part of the fuel being, in connection with the combustion of its first part, converted into fluid (secondary) fuel and burnt in the working medium before the completion'of its expansion in the turbine.
3. In combination, ak multi-stage gas turbine, a rotary compressor supplying compressed working medium for the gas turbine, a heat exchange device composed of metal sheets and connected, on the one hand, between the said compressor and the turbine and, on the other hand, into the exhaust pipe line of the turbine, a firing or combustion apparatus, suitablefor the complete combustion of one part, and, by means of 1ncomplete combustion, for the conversion into fluid fuel of another part of the fuel contained in it, being inserted into the exhaust pipe line of the said turbine between the outlet opening of the turbine and the heat exchange device, combustion chambers for the combustion of the fluidified (secondary) fuel joining on to the flow path of the working medium between the high-pressure outlet opening of the said heat exchange device and the exhaust opening of the turbine. separate ducts for leading the burnt gases of the said combustion apparatus through the said heat exchange device into the atmosphere and the secondary fuel, respectively, to the said combustion chambers, means as pumps or compressors for increasing the pressure of the secondary fuel inserted into the corresponding ducts, a duct branch in the said exhaust pipe line by-passing the said firing apparatus, and distributing organs as valves'in the exhaust pipe branches leading to the said heat exchange device and by-passing it, respectively, being adjustable in such a manner that at least a portion of the expanded working medium should ilow through the said firing apparatus, whilst another portion thereof should be mixed, by means of the said by-pass duct, to the burnt gases entering the heat exchange device.
4. In combination, a multi-stage gas turbine, a rotary compressor supplying compressed working medium for the gas turbine, a heat exchange device composed of metal sheets and connected.
on the one hand, between the said compressor and the turbine and, on the other hand, into the exhaust pipe line of the turbine, a suction fan in the outlet duct of the heat exchange device serving for the removal of the expanded working mee0 dium therefrom, a firing or combustion appafuel joining on tothe flow path of the working medium between the high-pressure outlet opening of the said heat exchange device and the exhaust opening of the turbine, separate ducts for leading the burnt gases of the said combustion apparatus through the`said heat exchange device into the atmosphere and the secondary fuel. respectively, to the said combustion cham-- bers, means as pumps or compressors for increasing the pressure of the secondary fuel inserted into the corresponding ducts, a duct branch in the said exhaust pipe line by-passing the said firing apparatus, and distributing organs as valves in the exhaust pipe branches leading to the said heat exchange device and by-passing it, respecs ,somes tively. being adjustable in such a manner that at least a portion oi' the expanded working medium should ow through the said nring apparatus, whilst another portion thereof should be mixed, by means of the said by-pass duct,'to the burnt gases entering the heat exchange device.