不同旋流数下湍流气粒两相流动特性的PDPA实验研究

EXPERIMENTAL STUDY ON TURNBULENT DILUTE GAS-PARTICLE FLOWS OF DIFFERENT SWIRLING INTENSITY

利用相位多普勒仪 (PDPA)系统研究了不同旋流数下突扩旋风筒内气粒两相湍流特性的变化规律 .在相同的进口形状和总风量的条件下 ,分别测量了旋流数为 0、 0 .5和 1.0时气相和颗粒相的轴向、切向的平均速度和脉动速度 .结果表明 :旋流数的变化对轴向速度的分布和切向速度的似固核 -位涡结构 ,以及两相脉动速度和两相湍流各向异性都有比较明显的规律性影响 ;总体上 ,旋流对两相湍流起抑制作用 ,但随旋流数的增大 ,两相湍流脉动及其各向异性都有先减弱 。

The dilute gas-particle flows in a cyclone chamber with axial and tangential inlers of different swirl numbers were studied by using a Phase-Doppler Particle Anemometer(PDPA).The measured two-phase axial,tangential time- averaged velocities and fluctuation velocities under the same overall air flow-rate,with swirl numbers of 0,0.5 and 1.0 respectively,are reported here.The results show that the swirl intensity has a remarkable effect on the profiles of axial velocity,the vortex structure of tangential velocity,the two-phase fluctuation velocity and the anisotropy of turbulence.The swirl can generally reduce two-phase turbulence.The intensity of turbulent fluctuation and its anisotropy decrease significantly with increasing swirl number at first,and they increase a little while the swirl number exceeds 1.