Fluid Inside Rectangular Microchannel Heat Sink Numerical Study On Flow And Heat Transfer Characteristics

In recent years,with the rapid iteration of electronic devices and the improvement of performance,the volume of electronic devices becomes smaller and smaller,which leads to a sharp increase in heat flux.Therefore,high requirements are put forward for the temperature control of electronic devices.The concept of microchannel heat sink first proposed in 1981 provides a reference for solving this problem.Microchannel heat sink is widely studied by researchers at home and abroad because of its large surface to volume ratio,simple structure and high convection heat transfer coefficient.There are many kinds of structures of microchannel heat sinks,most of which are rectangular microchannel heat sinks.In this paper,rectangular ribs are built on this basis to achieve the purpose of single and double layer structure.The overall flow and heat transfer characteristics of the microchannel heat sink are analyzed by changing the relevant parameters of the built-in ribs,namely,different lengths,different angles and different thicknesses.The effect of optimizing the overall structure is achieved by elaborating the internal mechanism of the relevant changes of parameters.Finally,through simulation and experimental research,the following conclusions are drawn:Based on the traditional rectangular microchannel heat sink,the overall design size,namely 50 mm * 22.5mm,is determined according to the relevant parameters of a certain battery.The parameters of a single microchannel heat sink are determined through calculation.On this basis,the single and double layer structure is achieved by means of built-in rib plate.The presence of built-in ribs can effectively enhance heat transfer,and also reduce the thermal resistance of the microchannel heat sink.With the increase of inlet velocity,the Nusselt number,pressure drop and pump work will increase.In terms of the length of the built-in rib plate,the length of the rib plate can effectively reduce the temperature of the bottom plate,but with the increase of the length,the Nusselt number does not increase blindly.In terms of the angle of the built-in rib plate,changes in different angles have little impact on the heat transfer of the overall structure.In terms of the thickness of the built-in rib plate,the thickness change of the rib plate has the greatest impact on the heat transfer of the overall structure,and also brings the maximum pump work.Compared with the traditional rectangular microchannel heat sink,at the same Reynolds number,the Nusselt number caused by length increases by 13.4%,the Nusselt number caused by angle increases by 6.7%,and the Nusselt number caused by thickness increases by 26.3%.Within the parameter range provided by the article,the overall structure was optimized by using the orthogonal experiment method.The Nusselt number and pump power were selected as the optimization objectives,and 13 groups of model experiments were conducted.The fitting was performed according to the secondorder curve.According to the fitting error,the fitting curve of Nusselt number was good and could effectively meet the engineering requirements,but for the fitting of pump power,although there were some errors,However,it can still meet the engineering requirements.Finally,according to the required optimization target parameters,namely the maximum Nusselt number and the minimum pump work.The final length,angle and thickness parameters are obtained.According to the parameter modeling and simulation,it is concluded that the optimized model increases the Nusselt number by 10.6%,and the pump power decreases by 8.7%compared with the minimum Nusselt number and the maximum pump power in 13 groups of data.Based on experimental principles,a heat transfer performance testing platform for rectangular microchannel heat sinks is constructed for experimental research,and experimental results are obtained while comparing with simulated data.In terms of measured physical pressure drop and maximum temperature of the bottom plate,the maximum pressure drop error is within 10%,and the maximum temperature error of the bottom plate is around 5%.