An experimental study on the effect of nanoparticle shape on the dynamics of Leidenfrost droplet impingement

Extensive investigations have been carried out on the thermo-hydrodynamics of nanofluid droplet interaction with heated and non-heated flat surfaces. However, the influence of shape of nanoparticles on the dynamics of droplet impingement on heated flat surfaces is yet to be explored in detail. In this study, hydrodynamics of nanofluid droplet impingement process on heated and mechanically polished aluminum substrate was studied using dissolved Al2O3 nanoparticles having spherical as well as cylindrical shapes. Nanofluids of 0.3% volume fractions were prepared from spherical Al2O3 particles of mean size less than 50 nm and from cylindrical Al2O3 particles of 2-6 nm in diameter and 200-400 nm in length. It was observed that, the impact dynamics is different from that of base pure fluid owing to the presence of nanoparticles. Leidenfrost temperatures of both nanofluids were dropped drastically in comparison with pure liquid. Further, the residence time, spread factor as well as retraction height also exhibit a different behavior against the base fluid. Detailed investigations were carried out for different Weber numbers (We = 18-159) and surface superheat and results obtained were compared with de-ionized (DI) water.

Automated summary

Extensive investigations have been conducted on the thermo-hydrodynamics of nanofluid droplets interacting with heated and non-heated flat surfaces, with a focus on the influence of nanoparticle shape on droplet impingement dynamics on heated flat surfaces. The study observed different impact dynamics, Leidenfrost temperatures, residence time, spread factor, and retraction height between nanofluids and base pure fluid. Detailed analyses were carried out for various Weber numbers and surface superheat values, showing significant differences compared to de-ionized water.