Numerical Simulation Of Fluid Flow In Microchannels With Designed Structure

Since the MEMS technology and nanometer technology obtained the unprecedented development in ten years,the world of humanity is from meters, centermeters toward the micron and nanometer micro, as an important branch of mems technology, micro fluid technology, in recent years, has had a huge development,and made a considerable progress. In the new era, electronic miniaturization is the inevitable trend. Such as time arises at the historic moment of miniature electronic components changed the human way of life, from then on into the "Micro Age".With the tendency of modern electronic components integration degree is higher and higher, a variety of electronic components of power is more and more intensive, local heat flux is more and more high, these integration components failure is one of the important reasons is that its working temperature is too high, they can’t run effectively, and even burn themselves out, lose their function. So, this brings the cooling technology several problems. For this kind of high integrated electronic components, microchannel heat sink is the most effective way, and it also is an important development direction in the field of heat dissipation.This paper has carried out the theoretical study of microchannel heat sink, and established the turbulence structure of microchannel model, as well as the traditional long straight microchannel model, and the corresponding research methods. By studying the traditional long straight microchannel in uniform temperature distribution and heat load in the thermal efficiency, analyzes the results and on the basis of traditional long straight microchannel scheme is improved, the specific implementation of the scheme is based on the traditional long straight microchannel, added a simple structure of the obstacles that turbulence structure, this kind of belt turbulence structure of microchannel is the use of the mechanism of heat transfer enhancement of obstacles to make produce radial fluid flow, thereby strengthening the micro channel and fluid mixing, and makes the fluid flow in the channel when disturbed flow vortex formation, undermining fluid flow boundary layer, disturbance of the fluid at the same time can obtain higher convection heat transfer coefficient, increase in thermal efficiency between the fluid and microchannel wall. Then studied the disturbed flow in terms of ribbed heat-exchange, respectively for the same length of microchannel set up 4 fins with 6 fins, to calculate the temperature distribution, and come to a conclusion. Then studied the inlet velocity influence on microchannel heat exchanger, set up five different inlet velocity, respectively to calculate its velocity field, temperature field, pressure field, the final analysis conclusions.Research method in this paper is to use the ANYSY ICEM CFD with disturbed flow structure of microchannel and traditional two-dimensional model of long straight microchannel, then defines model separately import to the FLUENT and fluid properties of solid materials before processing, and then choose the SIMPLE algorithm under the condition of uniform heat flow load, simulation calculation of traditional long straight microchannel respectively with disturbed flow structure of microchannel flow situation, studies the different density degree of disturbed flow calculation and analysis of fins. and then set different inlet velocity will get the temperature distribution of cloud, pressure field, velocity vector chart, temperature distribution and the heat source of fluid-solid interface temperature distribution, the final analysis it is concluded that the conclusion is:(1) Increases as the inlet velocity, Reynolds number increases, the pressure drop also increase, which shall provide microchannel flow conveying power increase.(2) To have been confirmed within the micro channel with water as working medium, microchannel heat transfer ability increased with the increase of flow velocity, when the inlet fluid flow rate increases to a certain extent, so the heat exchange capacity to maintain at a stable level. So in a certain range, can increase the fluid velocity, has reached the purpose of enhancing heat transfer effect.(3) When given the size of the microchannel, the microchannel heat transfer increases with the increase of Reynolds number; As to a certain extent, microchannel heat transfer also gradually leveled off, the heat transfer effect remain unchanged.