Experimental Investigation On Heat Transfer Of Heat Pipes Using Nanofluids Combination With Different Wicks

Starting from the two core components: working fluid and capillary wick, whichcould affect the performance of heat pipe.Nanofluids as working medium of copperwire mesh and foam liquid copper core tube were designed and fabricated.Anexperimental equipment for testing heat pipe was set up,Four factors witch affected the performance of different wick structures,nanofluids,liquid-filled ratio and mass concentration were analysised by theorthogonal experiment.And on this basis，the study on the characteristics of heat transfer in the test heatpipe was performed experimentally. The result is obtained in terms of axialtemperature distribution, the maximum heat transfer, thermal resistance, condensationand vaporator heat transfer coefficient, etc.Experimental results in the experiment of heat pipe indicate that:(1)Analyses the influencing degree of each factor on the heat transferperformance of heat pipe by the orthogonal experiment, were in the followingorder:different wick structures, liquid-filled ratio, nanofluids and mass concentration.(2)There has obvious differences in heat transfer efficiency of heat pipes withdifferent wicks. It can be proved that200ppi porous copper foam wick can enhancethe heat transfer compared with that of copper mesh wick, and shows excellentisothermal characteristics and about50%reduction in thermal resistance.(3)Compared with Al2O3nanoparticle and SiO2nanoparticle,CuO nanoparticlecould greatly enhance the coefficients of heat transfer and improve the maximum heatflux in the heat pipe.(4)The thermal performance of copper wire-bonded flat heat pipe increased withincreasing of the particle concentration in water and then decreased apparently whichindicated that an optimal particle concentration in water existed.(5) Synthesizes the various factors,0.5%mass concentration Al2O3nanofluidsand50%work filling ratio and200ppi porous copper foam wick is the optimal choice,results in the best heat transfer. It can meet the engineering application demands thatthe highest temperature in evaporation is lower than85℃while less than10℃difference in evaporation section and adiabatic section.