Heat transfer and entropy generation analysis of nanofluids thermocapillary convection around a bubble in a cavity

Abstract

In view of the fact that thermocapillary convection is an important heat transfer mechanism in nucleate boiling, and nanofluids is used to be heat transfer medium extensively. The present paper reports the numerical investigation of nanofluids thermocapillary convection around a gas bubble in a cavity, and the effects of nanoparticles volume fraction and size on flow characteristics, heat transfer performance and entropy generation are studied. The results show that, with more nanoparticles add to base fluid can enhance the heat transfer performance of gas bubble thermocapillary convection, the convective intensity is reduced, and the local entropy generation decreases and its distribution becomes more uniform. However, with larger nanoparticles diameter the results are just the opposite, namely, the heat transfer performance is weakened, the convective intensity is enhanced and the total entropy generation increases and its distribution becomes more nonuniform. These findings are of significance for the heat transfer enhancement in nanofluid boiling heat transfer.