|Publication number||USRE40512 E1|
|Application number||US 10/870,903|
|Publication date||Sep 23, 2008|
|Filing date||Jun 18, 2004|
|Priority date||Jun 23, 1999|
|Also published as||US6405794|
|Publication number||10870903, 870903, US RE40512 E1, US RE40512E1, US-E1-RE40512, USRE40512 E1, USRE40512E1|
|Inventors||Seo Young Kim, Byung Ha Kang, Jin Wook Paek, Sung Ki Kim|
|Original Assignee||Samsung Electronics Co., Ltd., Korea Institute Of Science And Technology|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (21), Non-Patent Citations (5), Classifications (13), Legal Events (3)|
|External Links: USPTO, USPTO Assignment, Espacenet|
1. Field of the Invention
The present invention relates to an acoustic convection apparatus for use in a system where uniform distribution of heat and density is needed and to a convective cooling at apparatus for cooling heat-generating components in electronic or electrical devices.
2. Description of the Related Art
As electronic devices become more complex and highly integrated, much effort has been made to improve the performance of apparatus for cooling such devices. To enhance the ability to dissipate heat from an electronic devices, such as computers or communication equipments, which contain many heat-generating components, heat should be forcibly transferred from the components to the surrounding cooling medium. As the electronic devices become more compact, passages of the cooling medium become narrower, thereby slowing the flow of the cooling medium. Moreover, in narrow passages, there exists only laminar flow without eddies. With the laminar flow, the cooling fluid is not actively mixed, which in turn prevents efficient convective heat transfer from the components to the cooling medium.
There have been several attempts to solve this problem. One of them is so called forced convection, which is to increase the velocity of the cooling medium by using a cooling fan or a pump. As the heat generation from the electronic components increases, the air flow rate should be increased by using a high powered fan or a pump. However, such a cooling system induces high power consumption and noise. Moreover, a fan or a pump cannot be easily used in very small devices.
Another approach is to shift the movement of the fluid from laminar to turbulent flow by adding turbulence-inducing material. However, these methods may suffer from noise and low reliance. The fan used for the cooling application is also being employed to enhance fluid mixing in thermal systems such as an oven, a furnace, a drying machine or a refrigerator. Air flow generated from the fan makes the distribution of temperature or density uniform to a certain degree. However, such a system also shows low efficiency because the air flow may not be uniform.
An object of the present invention is therefore to provide a convection apparatus which reduces the nonuniformity of air flow in a space where uniform distribution of temperature and density is needed, thereby improving the efficiency of an overall system disposed in the space.
Another object of the present invention is to provide a convective cooling apparatus for effective heat dissipation from electronic devices, which are compact and lightweighted.
In accordance with an aspect of the present invention, there is provided a convection apparatus for providing convective flow of medium in a system, which comprises a driver for generating a driving signal with a predetermined frequency and a vibrator, in response to the driving signal, for generating acoustic waves to an interior of said system.
In accordance with another aspect of the present invention, there is provided a convective cooling apparatus for cooling an electronic device including at least one heat-generating component and enclosed in a case having cooling medium therein. The convective cooling apparatus of the present invention neither attempts to increase the velocity of flow in the cooling fluid nor replaces the cooling medium with other material as prior art cooling apparatus did. Instead, it utilizes the hydraulic instability which is inherent in the flow of the cooling medium. In the convective cooling apparatus of the present invention, by using a driver for generating a signal tuned to a characteristic frequency of flow, an acoustic vibrator is driven to provide acoustic waves. The acoustic waves induce resonance in flow, which renders the cooling fluid vigorously mixed, which, in turn, enhances the heat dissipation from the device.
The aforementioned aspect and other features of the invention are explained in the following description, taken in conjunction with the accompanying drawings wherein:
The signal generator 1 provides a time-periodic electrical signal such as a sinusoidal, sawtooth or rectangular wave. The generated signal is voltage and current amplified in the amplifier 2. The amplified signal is sent to the vibrator 4 as a driving signal which drives the vibrator 4 to generate time-periodic acoustic waves. When a user turns on a switch (not shown) of the convection apparatus, the driving signal is provided from the driver 3 to the vibrator 4. In response, the vibrator 4 provides acoustic waves which cause an acoustic convection by which one can obtain uniform distribution of heat and density in a space where the convection apparatus is located.
In the signal generator 1, the frequency of the time-periodic signal may be determined in a couple of ways which will be described in detail with reference to
An acoustic vibrator 5 is located on the inner wall near the center of the oven so that it can provide acoustic waves to the interior of the oven 9. A driver 7 is built on a control board at the upper part of the oven. When a convection switch 6 is turned on, the driver 7 provides a driving signal to the acoustic vibrator S. The acoustic vibrator 5 then provides acoustic waves to the interior of the oven 9, thereby making the heat distribution in the oven uniform.
By inducing uniform distribution of heat and density, the convection apparatus of the present invention increases the efficiency and thus reduces the energy consumption of a system where it is used. The convection apparatus may be applied to a refrigerator, a freezer, a drying machine or a welding furnace to improve the efficiency thereof. It may also be used to improve the air distribution of an air-conditioned space.
The convection apparatus described above can be used for cooling electronic devices. The convection apparatus provides cooling effects by increasing the convective flow of cooling medium over heat-generating components in such devices.
The cooling apparatus 10 includes a signal detector 11 for receiving a flow signal from the cooling medium in the case 17, a driver 20 for generating a driving signal, an acoustic vibrator 16 for providing acoustic waves to the interior of the case 17 in response to the driving signal. In household electronic devices, the cooling medium would typically be air.
The signal detector 11 is disposed near the heat-generating component 18 to receive a flow signal, i.e., a signal induced by the flow of the cooling medium in the case 17. The signal detector 11 may comprise at least one of a velocity, a temperature, a pressure and a density sensors.
The flow signal detected at the signal detector 11 is sent to the driver 20 which includes a frequency analyzer 12 for analyzing the flow signal to determine a characteristic frequency of flow, a frequency synchronizer 13 for providing a frequency signal which represents the characteristic frequency determined in the frequency analyzer 12, a signal generator 14 for generating the driving signal in response to the frequency signal, and an amplifier 15 for amplifying the driving signal.
Specifically, the flow signal is first sent to the frequency analyzer 12 which analyzes the frequency components of the flow signal by using the fast fourier transform and detect a characteristic frequency of flow, i.e., a dominant frequency among the analyzed frequency components of the flow signal.
The characteristic frequency detected in the frequency analyzer 12 is provided to the frequency synchronizer 13 which provides the frequency signal, i.e., a signal representing the characteristic frequency, to the signal generator 14. The frequency signal may have any format as long as it conforms with an input of the signal generator 14.
The signal generator 14 generates the driving signal in response to the frequency signal. The driving signal may be any signal having the characteristic frequency, such as a sine wave, a sawtooth wave, or a rectangular wave, although a sine wave is preferred to minimize noises generated from the apparatus 10. The driving signal is amplified at the amplifier 15 and then fed to the acoustic vibrator 16.
The acoustic vibrator 16 generates acoustic waves having the characteristic frequency of flow in response to the amplified driving signal. The acoustic vibrator 16 may be implemented by using an acoustic speaker capable of easily generating acoustic waves. Alternatively, a piston, a cam, a membrane or a flap associated with a motor may perform the same function. The acoustic waves cause a resonance in the flow within the case 17, which activates heat transfer from the heat-generating component 11 to the ambient atmosphere through the heat dissipating opening 19. The acoustic vibrator 16 may be located in any wall of the case as long as the acoustic waves are directed to the interior of the case 17. Alternatively, a small acoustic vibrator may be placed near the heat-generating component 18.
In the cooling apparatus 10 or 30, the characteristic frequency of flow is less than several hundred Hz which is much lower than the mechanical resonant frequency of the electronic appliances. Thus, the application of the acoustic waves does not have an adverse effect on the structural stability of the devices. Moreover, compared with prior art cooling apparatus employing a fan to promote the movement of the cooling medium, the apparatus of the present invention produces less noise and can be built more compactly.
To find out the performance of the cooling apparatus of the present invention, experiments were conducted using an electronic device having a heat-generating component and including the cooling apparatus of the present invention.
To find out the effect of the amplitude of the driving signal on the temperature change, the cooling apparatus was operated with a fixed frequency of 50 Hz while varying the amplitude of the signal fed to the acoustic vibrator. Rate of temperature change is depicted in
The effects of the frequency and amplitude of a driving signal on the temperature change is summarized in
The cooling apparatus of the present invention can be easily incorporated into portable computers and communication devices having very small space inside. The cooling apparatus can be easily optimized to provide maximum cooling effects by adjusting a vibrating frequency. While a number of fans are needed to effectively cool a device having many heat-generating components, one cooling apparatus of the present invention is sufficient to cool such a device. In sum, the apparatus of the present invention provides improved cooling performance while allowing the devices to become smaller, lighter and less noisy.
The cooling apparatus of the present invention can also be used in a power converter and an atomic reactor where cooling performance has a critical impact on the operation and safety of the overall system. It can also be employed in a heat exchanger for chemical processes, a refrigerating and air-conditioning system, and a radiator system for heating and cooling a building.
The present invention has been described with reference to a particular embodiment in connection with a particular application. Those having ordinary skill in the art and access to the teachings of the present invention will recognize additional modifications and applications within the scope of the present invention. It is therefore intended by the appended claims to cover any and all such applications, modifications, and embodiments within the scope of the present invention.
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|5||The official action issued by the Japanese Patent Office on Oct. 12, 2004.|
|U.S. Classification||165/286, 165/300, 126/91.00A, 165/84, 165/104.33|
|International Classification||H05K7/20, F28F13/10, H01L23/467, F28F13/02|
|Cooperative Classification||H01L23/467, F28F13/10, H01L2924/0002|
|Jun 18, 2004||AS||Assignment|
Owner name: SAMSUNG ELECTRONICS CO., LTD., KOREA, REPUBLIC OF
Free format text: ASSIGNMENT OF 50% OF OWNERSHIP TO SAMSUMG ELECTR.;ASSIGNOR:KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY;REEL/FRAME:015491/0193
Effective date: 20040618
|Nov 18, 2009||FPAY||Fee payment|
Year of fee payment: 8
|Dec 13, 2013||FPAY||Fee payment|
Year of fee payment: 12