Effect of large temperature difference on drag coefficient and Nusselt number of an ellipsoidal particle in compressible viscous flow

Particle-resolved simulation which fully considers the temperature-dependence of fluid properties is performed to study the momentum and heat transfer between a high-temperature ellipsoidal particle and the fluid. A non-Boussinesq regime is first identified with the Richardson number larger than unity. The drag coefficient CD and Nusselt number Nu increase significantly with particle temperature. The increased pressure difference and the increased friction drag play the dominant role in the increase of CD at small and large incident angles, respectively. The increase of Nusselt number is mainly due to the increase of the thermal conductivity. The relationship between CD and the incident angle φ satisfies sin2φ, while Nu evolves as sinmφ, where m is a function of Reynolds number and aspect ratio. The values of CD and Nu at φ = 0° and φ = 90° are fitted from simulation results and values at any incident angle can be predicted based on functions of sin2φ and sinmφ.