Determination of aerodynamic and themal correlations for ellipsoidal particles via direct numerical simulation*

 

Direct numerical simulations of the flow and temperature field for a fixed prolate ellipsoid at constant surface temperature in uniform flow are performed. The parameter space defined by the Reynolds number 1 ≤ Re ≤ 100, aspect ratio 1 ≤ β ≤ 8, inclination angle 0⁰ ≤ Ø ≤ 90⁰, and temperature ratio 0.35 ≤ T_R ≤ 1.65 is covered by more than 6,600 computations. Flow fields and temperature fields are visualized for selected configurations. The aspect ratio less than 3 is identified to define the transitional geometries to fibers while higher aspect ratios hardly change the flow topology. The onset of flow separation is analyzed in detail. The heat transfer is primarily determined by the Reynolds number and the temperature ratio. The impact of the inclination angle on the heat transfer increases at higher aspect ratios. The data base is used to determine correlations for drag, lift, torque, and wall-heat transfer. The comparison with the DNS data shows that the fluid-particle dynamics is accurately modeled by the novel correlations.