Investigation of convective heat transfer from a high temperature prolate spheroid to moving fluid

Abstract

Most of the currently used fluid-solid heat transfer models assume that solid particles are perfect spheres. Heat transfer between non-spherical particles and flowing fluids acquires great importance in many engineering appliances. A numerical study is performed on airflow past a stationary confined prolate spheroid under the forced convective heat transfer regime, and the influence of non-sphericity of the particle on their heating rate is examined. The prolate spheroid is assumed to be maintained at a constant wall temperature. The effect of Reynolds number (Re) and Aspect Ratio (AR) on convective heat transfer rate and Nusselt number was investigated by solving steady-state Navier-Stokes and energy equations. The influence of the flow in terms of Reynolds number and the prolate spheroid aspect ratio was investigated. The spheroid’s surface temperature (Ts) was varied between 294 K and 1500 K. The simulations show that the mean Nusselt number has a positive dependence on Ts, AR, and Re. A new correlation was developed to predict the mean Nusselt number for a wide range of temperature differences. The new correlation consolidates the influence of aspect ratio, surface temperature, and Reynolds number, in contrast to the existing correlations that assume merely isothermal conditions to calculate the mean Nusselt number for spheroid particles.