A Microchannel Minimum Thermal Resistance Structure Optimization Method Based on Inlet Development Characteristics

A development characteristic, micro-channel technology, applied in special data processing applications, instruments, electrical digital data processing, etc., can solve problems that do not conform to the actual situation, micro-scale heat exchanger design troubles, etc.

Active Publication Date: 2016-02-24
ZHENGZHOU UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The existing optimization design methods of microchannel structures often ignore the influence of the inlet section, and the results of the optimization design often do not conform to the actual situation, which brings troubles to the design of micro-scale heat exchangers

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  • A Microchannel Minimum Thermal Resistance Structure Optimization Method Based on Inlet Development Characteristics
  • A Microchannel Minimum Thermal Resistance Structure Optimization Method Based on Inlet Development Characteristics
  • A Microchannel Minimum Thermal Resistance Structure Optimization Method Based on Inlet Development Characteristics

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Embodiment 1

[0054] Influence of embodiment 1 inlet effect on fluid flow

[0055] Because microchannel heat exchangers are limited in size, shorter channels need to be studied in order to meet actual needs, and the channel length has an important impact on the state of fluid flow.

[0056] The velocity distribution of the central axis of the fluid (X=0~40mm, Y=0.4mm, Z=0mm) is analyzed for the rectangular channel with length L=8mm, Reynolds number Re=500, and aspect ratio α=1, such as figure 2 (a) shown. It can be seen that the velocity of the central axis of the fluid increases continuously with the flow direction, indicating that the channel flow has not been fully developed. The fluid flow range is in the inlet development section, and the degree of fluid flow is more disturbed, resulting in different flow characteristics from the scale of the fully developed section. Since the velocity boundary layer is thinner and the velocity gradient is larger in the flow inlet section, the fricti...

Embodiment 2

[0061] Embodiment 2 The influence of entrance effect on heat transfer

[0062] The heat transfer characteristics of rectangular channels with an equivalent diameter of 0.4mm, an aspect ratio of 1, and lengths of L=8mm, 20mm, and 40mm were studied, and the following results were obtained: Image 6 The results shown. It can be seen that Nu decreases with the increase of the length. Under the same Reynolds number, the heat transfer performance of the fluid in the microchannel when L=8mm is about twice that of L=40mm, indicating that the shorter the length of the microchannel, the better the heat transfer performance. The higher the performance. This is because the fluid is heated from the inlet of the pipe, and the temperature boundary layer in the pipe is developing at the same time. Nu is the largest at the inlet, and then decreases greatly in the short flow length, and then slows down with the flow direction decrease, such as Figure 7 shown. This shows that the convective...

Embodiment 3

[0064] Heat transfer correlation formula under the inlet effect of embodiment 3

[0065] For microchannel heat exchangers with length L=8mm, 10mm, 15mm, equivalent diameter of 0.4mm, and different aspect ratios (α=1, 2, 4, 5), the fluids in the channels are all in the inlet development stage, respectively The heat transfer coefficient Nu is calculated under the conditions of laminar flow (Re<2000) and turbulent flow (2000≤Re≤6000), and the correlation formula for the heat transfer coefficient Nu of the fluid in the inlet development section of the microchannel is obtained by fitting, which is relatively With a 15% error:

[0066] Nu=1.183Re 0.350 alpha 0.242 (L / D h ) -0.216 PR 1 / 3 (Re<2000);(1)

[0067] Nu=10.664Re 0.269 alpha -0.074 (L / D h ) -0.402 PR 1 / 3 (2000≤Re≤6000)(2)

[0068] From Equation 1 and Equation 2, it can be seen that when the fluid in the microchannel is in the development stage of the laminar flow inlet, Nu increases with the increase of the aspec...

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Abstract

The invention discloses a micro-channel minimum thermal resistance structure optimization method based on access development characteristics. The method includes the steps of researching and analyzing the influence of the micro-channel access effect on fluid flow through a CFD method, researching and analyzing the influence of the micro-channel access effect on heat exchange through the CFD method, enabling the influence factors of fluid flow in an access section and heat exchange to be taken into consideration on the basis of analyzing the influence of the access effect on fluid flow and heat exchange through the CFD method, conducting programming computing through a MATLAB, conducting solving through nonlinearity integer programming, conducting secondary approximation on a Lagrange function in the solving process, and finally obtaining the optima solution of a target function. The optimal design is conducted on the micro-channel structure on the basis of enabling the access effect to be fully taken into consideration, based on the fluid flow access effect characteristics, with the minimum thermal resistance as an optimization objective and through the nonlinearity integer programming method, and the micro-channel minimum thermal resistance structure optimization method more corresponds to a practical situation.

Description

technical field [0001] The invention belongs to the technical field of microelectronic equipment, and relates to a microchannel minimum thermal resistance structure optimization method based on inlet development characteristics. Background technique [0002] With the application of microelectronics technology and VLSI technology in aerospace, communication, biology, optoelectronics and other industries, electronic equipment is rapidly developing towards miniaturization, high integration and high power. But at the same time, the high-temperature failure of microelectronic devices caused by high integration and high power is becoming more and more serious. Thermal design and thermal control have become key issues in the development and breakthrough of microelectronic technology. [0003] The main reason for the failure of microelectronic equipment is that the main frequency and integration of microprocessor chips are getting higher and higher, resulting in high power consumpti...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F17/50
Inventor 靳遵龙陈晓堂张志超王永庆雷佩玉郭月明刘敏珊
Owner ZHENGZHOU UNIV
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