旋流泵内部盐析两相流速度场的PDPA实验

以旋流式模型泵内部氯化钠盐析两相流场为研究对象,采用相位多普勒粒子测速仪(PDPA)对该泵在最优工况下的两相速度场进行了测量,给出各相在无叶腔及叶轮内部的三维速度及其对应的脉动速度分布曲线.通过对两相的周向速度、轴向速度及径向速度分布情况的分析,揭示了该型泵内盐析两相流速度场的分布特征.泵内同时存在循环流与贯通流,是强制涡旋和自由涡旋的叠加,与前人提出的流动模型相符;在叶轮进口处,液流已有强力预旋;随着半径增大,两相的周向和轴向速度呈现先增大后减小趋势,而径向速度先减小后增大,对应的脉动速度变化趋势则相反;泵内两相速度及脉动速度有滑移,但差异总体上并不显著.本文的研究有助于进一步认识盐析与流动的关系.

EXPERIMENTAL INVESTIGATION OF SALT-OUT TWO-PHASE FLOW IN A VORTEX PUMP BY PDPA MEASUREMENTS

Phase Doppler Particle Anemometer(PDPA)was used to investigate the salt-out two-phase flow in a vortex model pump.Velocity distributions of two phases were measured at the best efficient point of the pump.Three-dimensional velocity and turbulent fluctuating were obtained and discussed to clarify the salt-out two-phase flow characteristics.The internal flow consists of through-flow and circulating-flow.Forced vortex and free vortex exist simultaneously according with the former flow models.The fluids have been pre-swirled at the inlet of impeller.Circumferential and axial velocity increases at first then decreases with radius increasing.Radial velocity distribution shows the opposite trend.Velocity and fluctuating of two phases have little slippage.It is helpful to understand the relations between salt-out and flow in the future.