The Study On Heat Transfer Performances Of Pulsating Heat Pipe Charged With The Acetone-based Mixtures

Pulsating heat pipe(PHP)is a cutting-edge cooling equipment,compared with the conventional heat pipe,with a smaller size,stronger environmental adaptability and better heat transfer performance,but the number ofthe factors affecting its performance can not be negelacted as well.Thus,the heat transfer mechanism is more complex the need for more in-depth research.In the paper,the binary mixtures PHP which is still lacking in the field,was studied in the way ofthe physical properties,phase transition to explore the heat-transfer difference between mixtures and pure components.In the study,a copper PHP with inner and outer diameter of 2mm,4mm was employed and the working fluidswere study: acetone,methanol,ethanol,water,and 1-pentanol.Studied filling ratio: 45-70%;heating power: 35-100 W.The study found:(1)In the low,medium filling rate(i.e.45%,55%),compared to pure water and acetone PHP,each ratio(i.e.1: 2,1: 4,1: 7)water / acetone mixture PHP has a stronger ability to resist dry-out,brought to the higher maximum heat power.In the high filling ratio(62%,70%),compared to mixtures,pure working fluid(i.e.water and acetone)PHP has better heat-transfer performance.Moreover,at higher heating heating power(i.e.65-100W),pure acetone PHPhas the same thermal resistance as the mixture PHP,but,pure component PHP thermal resistance has been lower than the mixed mixture.(2)In the low ability to withstand dry out the filling rate(i.e.45%,55%),methanol/acetone mixed refrigerants PHP with pure components(i.e.methanol,acetone)is similar,did not reflect a significant improvement in the oscillation Shaogan heat pipe performance.In high filling rate(62% vs.70%),methanol/acetone mixed refrigerants PHP with its pure refrigerant heat transfer performance shape oscillations.This may be due to the physical properties of methanol and acetone on a strong similarity,resulting mixtures are more similar to pure working fluids,so that the mixing of pure refrigerants and refrigerant similar oscillating heat pipe heat transfer performance.(3)In the low,medium filling rate(i.e.45%,55%),ethanol/acetone mixture shows the similar capability resisting dry-out as pure components(i.e.ethanol,acetone).In the high filling rate(i.e.62%,70%),ethanol/acetone mixture and pure compoents present similar heat-transfer performance PHP.(4)In the low,medium filling ratio(i.e.45%,55%),1-pentanol/acetone mixture and pure component PHPhave the same ability to withstand dry-out.In the high filling rate(i.e.62%,70%),pure acetone PHP heat transfer performance is superior to 1-pentanol and 1-pentanol/acetone oscillating heat pipe.This is probably due to the high dynamic viscosity and density of 1-pentanol,such that pure monohydric pentanol refrigerants and pentanol/acetone mixed refrigerant flow rate within the tube decrease,resulting in oscillating heat pipe heat transfer performance weak at one yuan acetone oscillating heat pipe.(5)In the low,medium filling rate(i.e.45%,55%),water/acetone and 1-pentanol PHP have stronger ability to withstand dry-out,compared to methanol/acetone and ethanol/acetone mixure.In the high filling rate(i.e.62%,70%),the heat-transfer performance of methanol/acetone and ethanol/acetone PHPare superior to the water/acetone and 1-pentanol/acetone.