静止水中に噴出される固液混相噴流の粒子運動 : 流体工学 , 流体機械

概要

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Particle laden water jet have been analyzed by means of a laser Doppler anemometer (LDA). Glass spheres of 389μm in mean diameter were loaded into the injection water by a particle mixer and after then injected into still water bath. The particle/water jet injectors were made by brass pipes of which diameters were 5 and 8 mm. The mean velocities of the center of the jet were set as 1.8 and 1.5 m/s for 5 and 8 mm pipes, respectively. The initial volume fraction was set as 0.087% in all experiments. The results of vertical relative velocity between particle and water indicate that the particles have same velocity as water at the outlet of the jet however particle velocities are larger than that of water at the expanded jet in downstream. From the results of the transverse relative velocity, it is considered that the particle can get larger velocity than water at a certain downstream from the outlet. These features are well explained by using local Stokes number defined by local time scale of the turbulence and particle time constant as well as Saffman's lift force.
2001-02-25