Numerical And Experimental Study On Single Phaseflow Heat Transfer Characteristics Of Three Dimensional Shunt Orifice Plate Manifold Microchannel

With the rapid development of highpower integrated circuits,traditional cooling methods can no longer meet the development needs of the new generation of integrated circuits.How to use the new heat transfer method to effectively improve the heat transfer performance of micro-channel and maintain better temperature uniformity has aroused widespread concern.This paper optimizes the traditional manifold microchannel heat sink,and proposes a new type of three-dimensional manifold orifice microchannel heat sink(OPMM).Experiment and numerical simulations are used to study and verify the flow heat transfer performance and temperature uniformity provide theoretical guidance and data support for further strengthening microchannel heat sink convection heat transfer.The experimental comparison of the heat transfer effect between the prepared silica nanofluids and deionized water was conducted to explore the possibility of further strengthening the heat transfer of the new structures on the basis of the existing structure optimization.The main contents of the research and the corresponding important conclusions are as follows:(1)A new three-dimensional orifice manifold microchannel heat sink was designed based on field synergy principle and effect of entrance section.The temperature uniformity of the new structure was studied through numerical simulation,and the effects of the deep-height ratio and inlet velocity on convective heat transfer of the micro-channel were also analyzed and compared.Considering the temperature non-uniformity caused by the hot spots mainly occurring in the surrounding locations,it is proposed to reduce the heating area while maintaining the same heating power.The results show that compared with the traditional structure,the new structure relies on the top header effect to evenly distribute the fluid and the wall temperature uniformity has been greatly improved.Comparing the two heat source layouts,it is found that reducing the heating zone reduces the occurrence of hot spots.With the increase of the inlet flow rate,the heat transfer coefficients of the three cross-section structures of the microchannels all increase and the pressure drop also increases.The cross-section(height x width)of 150 μm x 40 μm has the best heat transfer effect but the maximum pressure drop.(2)A microchannel convection heat transfer test bench was built,and the experimental result was compared with the traditional single-straight microchannel heat sink and the traditional manifold microchannel heat sink.Based on field synergy principle,the theoretical analysis of the heat transfer enhancement of the new structure is performed.It is found that the numerical simulation results are in good agreement with the experimental results,which proves that the temperature uniformity of the microchannel heat sink can be verified by the numerical simulation results.The results show that the new micro channel is better than the traditional structure at constant heat flux and the same pump power consumption.Under a certain flow rate,it is found that the thermal resistance under different heat flux varies,and the thermal resistance increases with the increase of heat flux,which is the heat transfer coefficient of the microchannel heat sink decreases slightly with the increase of heat flow density.There is an optimal pump power for different constant heat flux densities,which can ensure that the heat exchange effect and economic effect are in a reasonable state at the same time.(3)Silica nanofluids were prepared by the two-step method and compared with the flow heat transfer effect of pure deionized water.The results show that: silica nanofluids has a strengthening effect on heat transfer within the range of heat flux in this experiment;Compared with deionized water,nanofluids have an enhanced heat transfer effect,and the corresponding pressure drop also increases.The pressure drop of nanofluids is higher than that of pure deionized water under different heat fluxes and flow.The pressure drop of nanofluids is higher than that of pure deionized water at different heat flux densities.Under the condition of low heat flux,the pressure drop difference between the two working media is not large with the increase of flow rate.With the further increase of heat flux,when the heat flux is higher than a certain value,the influence of the increase in flow rate of pure deionized water on pressure drop is lower than that of nanofluids.