振动幅度对两相流局部参数变化影响研究

Investigation of Vibration Amplitude Effect on Local Flow Parameters of Two-Phase Flow

为研究实验段振动对管内两相流局部参数变化的影响,利用电导探针技术对振动状态下局部两相流特性参数包括空泡份额、气泡直径和界面浓度进行了测量。实验首先在静态工况下进行,通过固定在实验段上方的偏心轮转动获得振动工况。实验段振动周期保持在0.5 s,偏心轮提供的振动幅度分别为4.8 mm、9.5mm和15.8 mm。实验结果表明,振动对环管内气-水两相流局部时均参数分布影响很小。但振动引起的附加惯性力作用使两相流局部参数径向分布在实验段振动周期中发生明显变化,而且局部参数的变化幅度随实验段振幅的增加而显著增大。在含气率较低的流动工况,当振幅增大到15.9 mm时振动工况下径向空泡份额峰值较静态工况下的空泡份额峰值的增量可以达到70%。但振动对局部流动参数的影响随气流量增大而降低。

In order to investigate the vibration effect on local two-phase flow parameters, local measurements of two-phase flow parameters including void fraction, Sauter mean diameter and interfacial area concentration were conducted using conductivity probe under vibration condition. The experiment was firstly conducted under static condition. The vibration modes were then imposed on the test section through the rotation of eccentric cam on the top of the test section. The vibration period of the test section was kept at 0.5 s and three vibration amplitudes, which were 4.8 mm, 9.5 mm and 15.9 mm respectively, were adopted. The experiment results showed that the vibration had very limited effects on the time-averaged local parameters of the gas-water two-phase flow. But the additional inertial force induced by the vibration would significantly change the distribution of local two-phase flow parameters in the annulus and the variations of local flow parameters increased greatly with the vibration amplitude. For the flow condition with lower void fraction, the non-dimensional void fraction peak can reach up to 70% as the vibration amplitude increased to 15.9 mm, but the vibration effect decreased with the increasing of gas flux.