Experimental Investigation on Turbulence Modulation in the Boundary Layer of a Horizontal Particle-laden Channel Flow with Relative Low Mass Loading Ratios
The turbulence modulations were experimentally investigated in the lower boundary layer of a fully developed horizontal channel flow. Polythene beads with diameters of 60um and 1 10um were used as dispersed phases, respectively. The particle mass loadings examined presently were 0, 2.5×10-4, 1×10-3 and 5×10-3. The corresponding volume fractions were 0, 2.85×10-7, 1.14×10-6 and 5.7×10-6. All experiments were performed at a wall Reynolds number of Reτ444, based on wall shear velocity uτ=0.445m/s and half channel height h=0.015m. The corresponding Reynolds number, based on the mean velocity and half channel height, Reh=6379. A simultaneous two-phase PIV measurement technique was adapted to acquire the turbulent statistics quantities for both gas and particle phases, and examine the coherent structures in the near-wall region. It is found that the presence of particles significantly modifies the turbulence of gas phase, even when the mass loading were at the order of 10-4. In the present low-mass-loading experiment, the velocity fluctuations of gas phase in both the streamwise and wall-normal directions and the shear Reynolds stress all considerably decreased in the lower boundary layer, excepting the velocity fluctuations of the streamwise component increased slightly in the near-core region (y+>100). The reduce of gas phase two-point correlations of both streamwise and wall-normal fluctuation velocities pointed out that the addition of particle resulted in weaker coherent structures in the turbulent boundary layer, with shorter streamwise extent of the quasistreamwise structures.
PIV turbulence modulation horizontal channel particle-laden flow boundary layers
J.Li H.F.Wang Z.H.Liu Y.M.Liu H.F.Han C.G.Zheng
State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, China
国际会议
西安
英文
436-441
2009-07-11（万方平台首次上网日期，不代表论文的发表时间）