不同密度材料颗粒对两相湍流调制的实验

 在颗粒雷诺数较小范围内,针对不同密度材料颗粒对气相湍流的调制规律进行了实验研究。采用相多普勒颗粒分析仪(PDPA)测量了气粒两相圆湍射流中气相速度和湍流度的分布,比较了相同形状、相同粒径和体积分数近似相同时玻璃微珠和聚苯乙烯颗粒分别存在时的两相射流流动的气相速度和湍流度。实验发现:不同密度材料的颗粒对气相平均速度的调制作用差别不明显,但对气相湍流度的调制作用显著不同。在近场区域,密度大的玻璃微珠对气相湍流度的增强作用高于密度小的聚苯乙烯颗粒;在远场区域,气相湍流度被削弱,并且密度大的玻璃微珠的削弱作用强于密度小的聚苯乙烯颗粒。该研究为进一步提出合理的两相湍射流的控制方法提供了理论依据和指导。

Experiments on Turbulence Modulation Caused by Particles with Different Material Density in Two-phase Round Turbulent Jet

This article makes an experimental study of gas-phase turbulence modulation by particles with different material density in small particle Reynolds number range. The gas-phase velocity and turbulence intensity are measured by means of a phase Doppler particle analyzer (PDPA) in a gas-particle round turbulent jet. The measured results of gas-phase velocity and turbulence intensity are compared when the jet is laden with glass or polyethylene particles of the same size and shape respectively. The particles volume fractions are approximately the same in the experiments. It is found that particles with different material densities have the same influence on the mean decaying velocity, while they have different influences on the turbulence intensity. In the near-fields, the gas-phase turbulence intensities are augmented more by glass particles with larger density than polyethylene particles with smaller density. In the far-fields, the gas-phase turbulence intensities are attenuated by particles and glass particles with larger density have a more pronounced effect on the attenuations of turbulence than the lighter polyethylene particles. The present study provides the theoretical reference and guidelines for proposing reasonable flow controlling methods of two-phase round turbulent jet.