Numerical analysis of sinusoidal and step pulse velocity effects on an impinging jet quenching process

摘要

In this paper, a numerical simulation of jet impingement quenching is provided. The VOF method in the basic solver of the OpenFOAM CFD package is developed to simulate boiling and condensation phenomena. In simulations, surface tension and mass transfer between two phases were modeled with continuous surface force (CSF) model and Lee mass transfer model, respectively, and energy equation was solved in the solid region. Numerical simulation of jet impingement quenching process is validated by experimental data and a good agreement is observed. The effects of pulsating jet velocity and step jet velocity on quenching process are studied, and parameters such as temporal and spatial variation of solid part temperature and standard temperature uniformity index (STUI) are investigated. The effects of frequency and amplitude of sinusoidal single jet and also the period of two jets with step pulse are investigated. The results revealed that using two jets with step velocity profile leads to the best performance or least uniformity index (best temperature distribution) among the considered cases. Studying the maximum temperature difference inside the solid region indicated that for pulse flows this parameter is considerably lower than the continuous flows. Also, at a constant flow rate, 43% reduction in STUI is achieved by sinusoidal pulsating jet compared to the single continuous jet, while 66% STUI reduction was reached for two-jet cases. These substantial reductions in uniformity index present these methods as promising approaches for the quenching process in various industrial applications.