Numerical simulation of surface vibration effects on improvement of pool boiling heat transfer characteristics of nanofluid

摘要

A numerical scheme for the effects of vibration on nanofluid pool boiling heat transfer was developed. For this purpose, a horizontal flat vibrating heated surface was considered. To model this phase-change phenomenon, the Eulerian-Eulerian approach was employed accompanied by the Rensselaer Polytechnic Institute (RPI) model to estimate the boiling heat flux on a solid surface, based on transient simulation. The k-epsilon turbulence model was used for simulating the Reynolds stresses appearing in the averaged Navier Stokes equation. The effects of the amplitude and frequency of vibration, nanofluid concentration along with magnitude of the heat flux on pool boiling heat transfer characteristics including heat transfer coefficient (HTC), vapor volume fraction and nanofluid velocity were studied. New analytical correlations for analyzing the heat transfer coefficient and nanofluid velocity based on the wall superheat temperature, amplitude and frequency of vibration were also developed. Results showed that applying mechanical vibration increased the boiling curve slope and the heat transfer coefficient. As a consequence, an increase of up to 30.11% and 17.5% in the heat transfer rate was achieved at lower heat fluxes for higher amplitude and frequency of oscillations, respectively.