سال انتشار: ۱۳۹۰

محل انتشار: نخستین کنفرانس خاورمیانه ای خشک کردن

تعداد صفحات: ۵

نویسنده(ها):

XU Peng – College of Science, China Jiliang University 258 Xueyuan Street, Xiasha Higher Education District, Hangzhou, 310018, China
QIU Shuxia – College of Science, China Jiliang University 258 Xueyuan Street, Xiasha Higher Education District, Hangzhou, 310018, China
MUJUMDAR Arun S – Department of Mechanical Engineering, National University of Singapore 9 Engineering Derive 1, 117576, Singapore
PANG Ning – Department of Mechanical Engineering, National University of Singapore 9 Engineering Derive 1, 117576, Singapore

چکیده:

The confined opposed-jet configuration of simple geometry and well-defined boundaries has several favorable heat and mass transfer features that can be exploited in novel dryer designs for particulate materials and sludges that can be dispersed in a gas steam. Prior work has considered stead jets impinging normally against each other. Here, we consider confined opposing jets which are two dimensional and in the turbulent flow regime. The periodic oscillations induced by pulsation show features such as flow instability, higher turbulence levels, chaotic mixing and a nonlinear dynamic response of the boundary layers. Thus, the potential advantages of pulsing one or both jets are evaluated using the computational fluid dynamic approach, where RNG k-ε turbulence model is used. The jet Reynolds numbers vary from 5,000 to 20,000, while the frequency and amplitude of oscillation of the jet range from 10 Hz and 20% to 200 Hz and 80%. Parametric studies are conducted for the optimization of unsteady turbulent opposed jets. The hydrodynamics characteristics are examined to better understand the mixing properties in unsteady turbulent opposed jets.