Development Of Spray Cooling Experimental Device And Study On Cooling Characteristics Of Porous Foam

With the rapid development of the integration and miniaturization of high-power electronic equipment,the control of the thermal environment of electronic equipment has become particularly important.How to effectively utilize the spray cooling technology with high heat flux cooling capacity and strict temperature control ability has become the research focus of scholars at home and abroad in recent years.In view of this problem,this paper takes the enhanced heat dissipation characteristics of high heat flux electronic equipment as the research object,and combines the porous foam to strengthen the heat dissipation and spray cooling technology,the combination of theoretical analysis and experimental measurement is used to analyze the key factors affecting the heat dissipation effect and comprehensively evaluate the thermal environment.The main work carried out in this paper is as follows:1.The experimental system design was carried out,and the key components of the heating system,the spray system and the data measurement system were designed,processed and researched,and a high-heat-power spray cooling test bench with water as the working medium was built.Investigate and select porous foamed metal with high thermal conductivity,low density,and porous foam with hydrophilic and capillary water absorption,the optimal injection distance was obtained in the early stage of the test and the test bench was debugged and improved.2.Under the condition of optimal injection distance,the experimental study measured the heat dissipation characteristics of nitrogen-carrying water droplets impinging on a simple heating surface at a certain speed,the effects of input heat flux,liquid flow and gas flow on heat transfer effects under different enhanced heat transfer conditions were investigated.Based on the above results,it is considered that at a low input heat flux density(generally lower than 50 W/cm~2),the larger the liquid flow rate,the lower the surface temperature,the maximum surface heat transfer coefficient can be obtained when the liquid flow rate is 1 L/h,but the control effect on the surface temperature is general.3.For the high-power spray cooling experiment process,it is difficult to achieve the steady state problem.Using the Fortran language calculation program,the one-dimensional unsteady heat conduction problem is modeled and solved,the internal temperature field of the heating column and the equivalent convective heat transfer coefficient of the spray surface were calculated.Experiments have found that at high input heat flux(generally above 50 W/cm~2),a larger liquid flow rate results in better cooling.4.The heat dissipation characteristics of the heated surface of the porous foam covered by a certain amount of nitrogen carrying water droplets were investigated experimentally,and the effects of different pore densities,material thicknesses and porosity on the heat transfer effect were discussed.It is found that the smaller the pore density of the covered foam,the lower the heat exchange surface temperature and the better the heat transfer enhancement effect.Moreover,a better heat exchange effect was obtained when a foam having a thickness of 3 mm and a porosity of 0.9 was used.