关键词: 纳米流体, 池内核态沸腾, 传热系数, 表面沉积, 接触角

Abstract: Heat transfer performance of nanofluids in nucleate pool boiling was experimentally investigated on a horizontal flat surface of cooper under atmospheric pressure.The surface roughness was controlled by sandpaper of grade 2000^#.The nanofluid was prepared by dispersing the δ-Al₂O₃ nanoparticle in the base fluid refrigerant 141b(R141b) in 0.001%,0.01% and 0.1% volume fractions.The results show that the heat transfer coefficient increases with the concentration of nanoparticle.Compared with the pure fluid R141b,the heat transfer coefficient is increased 50.2% for 0.1% volume fraction averagely under 30—130 kW·m^-2 heat flux.The surface deposition of particles is observed as one of the major factors for the enhancement.For pure R141b and low concentration nanofluid,the experimental results agreed well with the predictive results based on Rohsenow’s correlation.The maximum relative error is less than 13%.At higher concentrations,the correlation is no longer applicable.

Key words: nanofluid, nucleate pool boiling, heat transfer coefficient, deposition, contact angle