Ethanol And Water Mixture Solution Applied In Spray Cooling Experiment Research

Heat flux has gradually increased because of the integration of electronic devices,which has become the main factor that curbs its development.Compared with the traditional way of heat transfer,spray cooling has the advantages of strong heat transfer,small demand of working medium,and compact structure.So the spray cooling is applied to electronic device cooling,which has broad application prospects.This paper attempts to mix ethanol with water as a cooling medium.Probe into the heat transfer characteristics of mixture in spray cooling.Based on this,this paper carried out the following several aspects:First of all,the construction of the spray cooling test bench is completed,test bench is mainly divided into three systems,respectively liquid supply and spray system,heating system and data acquisition system.Focus on the description of main equipments of each system,as well as the attention in the process of building.Finally,fulfill the data processing and error analysis.Then,mix ethanol with water as cooling medium,and the volume fraction of ethanol is respectively 0%(pure water),0.5%,1%,2%,3%,4%,5%,10%.First carry on the mixed solution surface tension and contact angle test,results show that the ethanol added can effectively reduce the surface tension of the droplet,leading smaller droplet and faster droplet speed,so heat transfer is enhanced.And adding ethanol can effectively reduce the surface contact angle,which is advantageous to the liquid film spreading so that the area of heat exchange will be increased and it prevents the appearance of the dry wall which is conductive to the effect of the heat exchange.And heat-exchange will be stimulated.Then apply mixture to spray cooling experiment,the experimental results show that adding ethanol can greatly enhance heat transfer.Especially when the wall temperature is in 80 ~ 100 ?,the improvement of the performance of the heat transfer is most obvious.Gradually increase the ethanol volume fraction,wall heat transfer performance firstly is enhanced and then decreased,and when the volume fraction of ethanol is 4%,the heat transfer performance is the best.Relative to the pure water cooling medium,the coefficient of heat transfer mostly increases by 38.4%.Finally,by changing the spray pressure,the calculation of atomization performance parameters is carried out.Both for pure water and the mixture,when increase spray pressure,the speed of the droplet Uo and the Weber number We will correspondingly increase,so that liquid film disturbance is strengthened,leading the enhancement of heat exchange.But compared to increase the spray pressure,adding ethanol makes the improvement of heat exchange more obvious.