| The application of microgrooves cooling technology in the fields of power and electronics is potential. Much research about microgrooves cooling and its application in power and electronics has finished by researchers. In this work, problems about flow and heat transfer in microgrooves are under research through experimental and theoretic methods. Besides, the application of microgrooves in cooling of laser has been developed experimentally.In this work, the flow rules of liquid in heated microgrooves are investigated by Micro-PIV method. The reverse flow phenomenon in microgrooves is found for the first time. The results show that with the increase of heat flux, the intensity of reverse flow in microgrooves increases at beginning, and then it decreases. The reverse flow is sensitive to the size of microgrooves. The flow in microgrooves can be divided into three regions, which are reverse flow region, main flow region and mixed flow region. In this work, the reason for reverse flow in microgrooves is also analyzed. We think the asymmetric evaporation of meniscus in heating region causes the reverse flow in microgrooves.In this work, the meniscus shapes in unheated microgrooves' cross-section are tested through the developed Micro-PIV system for the first time. The results show that the meniscus shapes in microgrooves are parabolic, which is different from previous assumption. In this case, we use the software Origin to fit the meniscus shapes, and obtain the fitting formulas of the meniscus shapes. Furthermore, the fitting formulas have been analyzed and compared. Based on the work above, the previous theory for predicting the wetting length of liquid in vertical microgrooves has been revised. In the new theory, the curvature for calculating wetting length equals to the average curvature of meniscus in vertical microgrooves subtracts the average curvature of meniscus in horizontal microgrooves. We compare the results from previous theory, the new theory and the experiment. The comparisons show that the results from new theory are much closer to the experimental results.In this work, the wetting speed of distilled water and ethanol in the vertical microgrooves is experimental investigated. Experimental results show the wetting process is not uniform. The wetting speed is very high at beginning, and then it decreases quickly to zero. The working fluid has a great influence to wetting speed and maximum wetting length in vertical microgrooves. Based on the experiments, a theoretical model is developed to predict the possible maximum heat flux distribution on the vertical microgrooves. Results from model show the possible maximum heat flux has different value at different positions of microgrooves for different working fluids. With the increase of height, the possible maximum heat flux on vertical microgrooves decreases from its maximum value at the entrance of liquid to zero at the highest point.Based on the experimental and theoretical work about the flow and heat transfer in microgrooves, a new cooling system combining microgrooves and thermoelectric cooling is developed to solve the cooling problem of laser. In this case, we change the initial design based on the result of the initial design. For the laser whose heat flux on surface and power are15.8W/m2and95W, the cooling system can make sure the temperature on laser's surface is less than26℃and the amplitude of temperature is±2℃. When the cooling system works, temperature of evaporator varies at the same direction with temperature of condenser. The temperatures of evaporator and condenser increase with the increase of laser's power. The capacity of TEC cooler and copper radiator has a great influence on the cooling system. In order to improve the cooling system, we should improve the TEC cooler and copper radiator.
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