Particulate Deposition Prediction of Diluted Two-Phase Impinging Jet

Abstract

Insights into particle transport and deposition process in impinging jet flow, in light of the available experiments, can be gained using computational fluid dynamics (CFD) numerical simulations. The present thesis focuses mainly on the prediction of aerosol particle transport and deposition in impinging jet flow. An extensive literature survey has indicated that the present work represents the first comprehensive investigation of aerosol particle transport and deposition, using Reynolds averaged Navier Stokes/eddy interaction model (RANS/EIM) along with near-wall corrections, and large eddy simulation (LES) numerical approaches applied to particle-laden impinging jet flow. A new in-house tracking code for particle-laden impinging jet flow using modified EIM, as well as modified EIM in conjunction with the near-wall correction technique based on impinging jet flow characteristics was developed to simulate the particulate phase. Two different approaches in the framework of RANS method, RANS SST (shear stress transport) and RANS RSM-BSL (Reynolds stress transport-Baseline) model were used to simulate the fluid phase in three cases of nozzle-to-surface distances of L/D = 2, 4 and 6. Also, to better understand the applicability and accuracy limits of different numerical methods on aerosol particle deposition, one representative case for an impinging jet flow of L/D = 2 was performed using LES. Deposition results without near-wall correction, with turbulent tracking, showed unrealistic behavior at the beginning of the wall jet region and close to the stagnation point. Once the normal-to-wall fluctuating velocity, which plays important role for particle deposition on the impingement wall, was properly modeled via the near-wall correction technique, significant improvements were obtained when compared to the previous experiments, for all L/D cases. However, the results showed that RANS RSM-BSL/modified EIM, in conjunction with the near-wall correction, have better performance in predicting the deposition results. Particle deposition results for L/D = 2 showed that LES is in closer agreement with previous experimental data more than RANS RSM-BSL/modified EIM along with near-wall correction. These results provide new insight into the general behavior of the aerosol particle transport and deposition process in impinging jet flow.