고체분말이 부상하는 2상 난류 수직관 유동에 대한 Lumley의 저항감소 모델의 적용(I) - 운동량 전달 기구

Abstract

A "Two-fluid model" has been incorporated with Lumley``s drag reduction model to analyze the mechanism of momentum transfer in the turbulent dilute gas-particle flow in a vertical pipe. The change of the effective viscous sublayer thickness by the presence of particles is modeled by Lumley``s theoretical model. The numerical computations of the friction factor and the pressure drop in the fully developed flow region are in good agreements with the corresponding experimental data with an average particle size of 15μm. It is proved that Lumley``s model is successful in predicting the correct reduction behavior of the drag in the gas-practice flows. As a result, the major cause of decrease in the friction factor at low loading ratio is the increase of viscous sublayer thickness caused by the suppression of turbulence near the wall by solid particles.