Laminar and turbulent flow and heat transfer characteristics of confined impinging streams

Studies were performed to investigate the flow, heat transfer as well as mixing characteristics of two-dimensional laminar and turbulent confined impinging streams. In the first part numerical simulations were conducted to study the flow and mixing behavior of two-dimensional laminar confined impinging streams. Reynolds numbers beyond which the flow becomes oscillatory and even random were determined for different geometric configurations. Simulations were performed for cases with jet Reynolds numbers in the stable regime to study the mixing characteristics of the system. Numerical simulations were also conducted to study fluid mixing in a novel two-dimensional in-line mixer utilizing multiple impinging stream inlets. Offsetting the top and bottom inlet jets is found effective in improving the quality of mixing due to the presence of intense mixing zones between the inlet jets.;In the second part a study of turbulent flow and heat transfer in two-dimensional confined impinging streams was conducted. A new composite turbulence model is proposed and verified by comparing its predictions with available experimental impingement heat transfer data as well as the experimental velocity and temperature distributions in impinging streams obtained in this work. Better agreement between experimental and numerical results predicted by this new model is noted compared to those predicted by other low-Reynolds number kappa-epsilon turbulence models tested. The model was then used to perform a parametric study of the mixing characteristics of two-dimensional turbulent confined impinging streams.;Finally, a numerical study of the gas-particle flow and drying in turbulent two-dimensional confined impinging streams was conducted. Continuous-phase conservation equations are written in the Eulerian frame while the particle equations are written in the Lagrangian frame. Two-way physical coupling between the continuous and particulate phases is taken into account in the governing conservation equations. Monte Carlo stochastic approach is used to model particle dispersion due to the turbulent fluctuations of the continuous-phase velocity. Effects of various operating parameters on the flow and drying behavior of the system are reported and discussed.