【摘要】 为了获得后台阶气粒两相湍流的流动特征,用相位Doppler粒子动态分析仪(PDPA)对其进行了实验研究。45μm颗粒速度几乎都大于相应位置上的气相速度,而脉动速度分布与气相相似,具有双峰结构。颗粒平均速度和脉动速度的分布在不同Re下是相似的,其流向脉动速度的最大值在7~8倍后台阶高度的流向距离之前,大致能够保持不变,但此后会显著减小,并在12倍后台阶高度的距离之后整个截面分布趋向均匀。随着Re的增大,颗粒相的回流区长度也逐渐变长。这些结果为认识颗粒相的流动规律以及发展和改进颗粒相数值模型提供了依据。更多还原

【Abstract】 Turbulent gas-particle flows over a backward-facing step were investigated experimentally using a Phase Doppler Particle analyzer (PDPA). The results show that the mean velocities of almost all the 45 μm particles are larger than the gas phase velocities at the same position due to the larger inertias of the particles, while the fluctuating particle velocity distributions are similar to the gas phase distributions, which are characterized by double peaks. The distributions of the mean and fluctuating velocities of the 45 μm particles at different Re are similar to each other. The maximum values of the fluctuating velocities at each section do not vary much before 7H8H in the streamwise direction, and then decrease quickly. After 12H, the fluctuating velocity distributions tend towards uniformity. The reattachment lengths of the particle phase increase with Re.更多还原