Experimental Study Of Pulsating Heat Pipe Stable Operation Withmethanol/Acetone As Working Fluid

According to the advent of technology in recent years,electronic elements integration and miniaturization become more intense,the calorific in unit volume is rapid rise,the problem of heat dissipation acute.Pulsating heat pipe(PHP)stand out with the advantages of simple structure?good heat transfer performance?variety structure?strong adaptability etc,it known as the most promising one of the means in solving the problem of narrow space with high heat flux cooling in the 21 st century.In order to further strengthen the pulsating heat pipe heat transfer performance,This paper tries to use mixed working medium research the pulsating heat pipe.This paper using the methanol/acetone mixed working medium in tubular PHP made a systematic experimental study.Firstly discusses the stability of the different mixing ratio of methanol/acetone mixed working medium PHP operation condition;(2)Studied the slope Angle of methanol/acetone mixed working medium affect thestart-up of PHP;(3)studied the slope angle?filling ratio?mixing volume ratio effect on PHP heat transfer performance.Experimental results show that:(1)In different maxing volume ratio,the temperature value and fluctuation also different when the methanol/acetoneMixed working medium PHPat stable operation,under the same conditions,the temprature value and fluctuation to the minimum when the methanol/acetone at1:5,in this maxing volume ratio,the heat-transfer performance is best,the thermal resistance was 0.15?/W.(2)Slope angle for the mixed working medium PHP had a great effect on start-up and heat-transfer characteristic,the methanol/acetoneMixed working medium PHP is hard to start-up when the slope angle was 0°,the slope angle has a certain effect of stable operation temperature but doesn't affect the mode of start-up;The influence of slope angle for PHP heat-transfer performance conformed to this rule that the greater slope angle has better heat-transfer performance and have larger initial power.(3)In small filling ratio(20%)or less,the methanol/acetoneMixed working medium PHP is easy to achieve the heat transfer limit and it heat pipe heat transfer limit in 60 W ~ 80 W,Methanol/acetone mixed medium PHP best filling ratio range is 40% ~ 60%.(4)Acetone content in the mixed working medium is more conducive to strengthen the mixed working medium PHP heat transfer performance,but the content of acetone is overmuch,the methanol/acetone mixed working medium PHP is easy to achieve heat transfer limit;The mixing volume ratio exist a critical value to divide the value of mixing valume ratio into two group,the mixing ratio in the same group is not obvious effect on heat transfer performance,but between different groups of mixing ratio on heat transfer performance is very obvious,and the value of the critical blending ratio in 2:1 ~ 1:2(methanol/acetone).