Torres, Jonathan. Boiling and spreading behavior of impinging nanofluid droplets on a heated surface. Retrieved from https://doi.org/doi:10.7282/T38C9V95
DescriptionThe effects of nanofluids on water drops impinging onto heated surfaces are studied. This includes analyzing the drop spreading and boiling behavior. In order to view the impingement of the drops, a transparent ITO (Indium Tin Oxide) coated quartz glass is modified into a transparent heater and is used to simulate the heated surface. Two different concentrations of alumina oxide nanoparticles are studied and compared to pure water. The drops are studied under 4 different Weber number conditions and surface temperatures in the range 100°C-200°C and 275°C. The boiling regions observed in this studied ranged from the convective boiling region to the film boiling region. Boiling properties of the drop are visualized with a high speed image acquisition system. The spread behavior of the droplets is studied and compared with analytical theories. Boiling behavior is significantly altered with the addition of nanofluids most significantly in the nucleate boiling region. Nanofluid drops show an increase in bubble production and growth when compared to pure water drops. As a result, the nanofluid drops experience a more intense nucleation boiling than water drops. The Leidenfrost temperature is also studied for the different nanofluid concentrations. Furthermore results show that nanofluids prevented the formation of dry areas at certain We and Ts, but when dry areas are present they last longer. Last, the spreading behavior of nanofluid drops registered higher β values especially at the higher Ts when compared to pure water. This is due to their increased amount of nucleation during the boiling of the drop.