Studies on gas turbulence and particle fluctuation in dense gas-particle flows |
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Authors: | Lixing Zhou Zhuoxiong Zeng |
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Institution: | (1) Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China;(2) Aeronautic and Mechanical Engineering College, Nanchang Hangkong University, Nanchang, 330034, China |
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Abstract: | Particle fluctuation and gas turbulence in dense gas-particle flows are less studied due to complexity of the phenomena. In
the present study, simulations of gas turbulent flows passing over a single particle are carried out first by using RANS modeling
with a Reynolds stress equation turbulence model and sufficiently fine grids, and then by using LES. The turbulence enhancement
by the particle wake effect is studied under various particle sizes and relative gas velocities, and the turbulence enhancement
is found proportional to the particle diameter and the square of velocity. Based on the above results, a turbulence enhancement
model for the particle-wake effect is proposed and is incorporated as a sub-model into a comprehensive two-phase flow model,
which is then used to simulate dilute gas-particle flows in a horizontal channel. The simulation results show that the predicted
gas turbulence by using the present model accounting for the particle wake effect is obviously in better agreement with the
experimental results than the prediction given by the model not accounting for the wake effect. Finally, the proposed model
is incorporated into another two-phase flow model to simulate dense gas- particle flows in a downer. The results show that
the particle wake effect not only enhances the gas turbulence, but also amplifies the particle fluctuation.
The project supported by the National Natural Science Foundation of China (50606026 and 50736006).
The English text was polished by Yunming Chen. |
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Keywords: | Particle fluctuation Gas turbulence Dense gas-particle flows |
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