Computational Fluid Dynamics of rising droplets

Wagner, Matthew¹  Francois, Marianne M.² 

[1] Lake Superior State University;Los Alamos National Laboratory

关键词: COMPUTERIZED SIMULATION;    CONVERGENCE;    FLUID MECHANICS;    NUCLEAR FUELS;    PERFORMANCE;    RESOLUTION;    SOLVENT EXTRACTION;    VELOCITY;    WALL EFFECTS;   

DOI  :  10.2172/1050489
RP-ID  :  LA-UR-12-24514
PID  :  OSTI ID: 1050489
Others  :  TRN: US1204703

美国|英语

来源: SciTech Connect

【 摘 要 】

The main goal of this study is to perform simulations of droplet dynamics using Truchas, a LANL-developed computational fluid dynamics (CFD) software, and compare them to a computational study of Hysing et al.[IJNMF, 2009, 60:1259]. Understanding droplet dynamics is of fundamental importance in liquid-liquid extraction, a process used in the nuclear fuel cycle to separate various components. Simulations of a single droplet rising by buoyancy are conducted in two-dimensions. Multiple parametric studies are carried out to ensure the problem set-up is optimized. An Interface Smoothing Length (ISL) study and mesh resolution study are performed to verify convergence of the calculations. ISL is a parameter for the interface curvature calculation. Further, wall effects are investigated and checked against existing correlations. The ISL study found that the optimal ISL value is 2.5{Delta}x, with {Delta}x being the mesh cell spacing. The mesh resolution study found that the optimal mesh resolution is d/h=40, for d=drop diameter and h={Delta}x. In order for wall effects on terminal velocity to be insignificant, a conservative wall width of 9d or a nonconservative wall width of 7d can be used. The percentage difference between Hysing et al.[IJNMF, 2009, 60:1259] and Truchas for the velocity profiles vary from 7.9% to 9.9%. The computed droplet velocity and interface profiles are found in agreement with the study. The CFD calculations are performed on multiple cores, using LANL's Institutional High Performance Computing.