| With the arrival of the era of big data,the computing load of chips is constantly increasing,and the chips are gradually developing towards to miniaturization.So the heat dissipation of chips has become the shackles of the development of information technology.How to eliminate the heat generated by chips efficiently and quickly is an urgent problem to be solved.Because of the limitation of air-cooled heat dissipation,and the important thing is that it can't achieve the same cooling effect while consuming a lot of electric energy,it has been unable to meet the heat dissipation needs of today's data center.The corresponding water-cooled heat dissipation has been advocated gradually because of its high efficiency and fast cooling effect.Unlike air-cooled heat dissipation,water-cooled heat dissipation should not only pay attention to the heat dissipation performance,but also consider the internal flow loss,so the heat dissipation performance can't be analyzed unilaterally in the research process.In this paper,the groove radiator is used as the research object.The structure optimization of the radiator is a key point of the research.The purpose of the structure optimization is to reduce the fluid flow loss in the groove while maintaining the high heat transfer effect of the water-cooled groove radiator.In the previous research on how to optimize the groove radiator,only one structure(channel width)is often concerned.The optimal combination of structural dimensions can't be obtained without analyzing the coupling effect of various parameters on the performance of radiator.In addition,the top cover of radiator is usually made of non-visual materials,the internal flow state is unknown,whether there are flow bubble can't be known,and the influence of bubbles on the performance of radiator has always been a blank point.Based on the above shortcomings,the research contents of this paper are as follows:Taking the total entropy increase as the target parameter,the structure size of the radiator is selected by orthogonal experiment method.The order of the influence of various structural parameters on the total entropy increase of the water-cooled groove radiator is studied.The optimal structure size combination of the water-cooled groove radiator is obtained.It is found that the most influential parameter is the channel height and the least influential parameter is the channel length.In addition,the optimum structure size combination is 75 mm channel length,4 mm channel height,0.5 mm channel width and 40 mm thermal diffusion plate edge length.By simulating the actual operation of water-cooled radiator in the cooling system of data center,the corresponding water-cooled groove radiator test-bed is built.Nusselt number and total thermal resistance Re are selected as the research index of radiator heat dissipation performance,and the pressure drop and friction coefficient f at the inlet and outlet of radiator are selected as the key parameters to study the fluidity performance.The optimum operating parameters of the existing channel radiator are as follows: cooling water flow rate is 0.6L/min,cooling water inlet temperature is 20 °C.The study on the existence of trapped bubbles in the groove shows that the trapped bubbles have an effect on the heat dissipation and flow performance of the groove radiator.The influence on the heat dissipation performance varies according to the length of the bubbles.When the bubbles are long(flow rate is 0.6 L/min),the bubbles inhibit the heat transfer process,while when the bubbles are short,the disturbance effect of bubbles on the flow of fluids will result in the effect of heat transfer enhancement.For the flow performance,the friction coefficient f and pressure drop in the presence of retained bubbles are higher than those in the normal channel.For the local entropy increase,because of the disturbance on the bubble wall and the low thermal conductivity in the air region,the local entropy increase caused by the flow friction and heat transfer occurs suddenly in the bubble region. |
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