新一代螺旋轴流式多相泵的外特性试验研究及数值模拟(英文)

以中国石油大学(北京)自主研发的新一代螺旋轴流式多相泵为研究对象,在不同工况下对其进行外特性试验研究.实验表明新一代螺旋轴流式多相泵能够输送很大范围的单相或多相流体.并且测定了转速、进口含气率、吸入压力等主要操作参数对多相泵性能的影响.通过实验发现多相泵的性能随着转数和进口吸入压力的提高得到明显改善,增压有所提高,高效区变宽,最优工况对应的流量增大.当含气率升高时,多相泵内两相流体产生速度滑移,泵内流型发生转变,导致多相泵振动、性能不稳定,多相泵的增压能力降低.另外多相泵入口处的均混器能够改善多相泵入口来流的条件,扩大多相泵的操作范围,对多相泵的性能影响很大.为了更好地了解多相泵内流场情况,建立了多相泵CFD数学模型.运用Fluent6.2进行数值模拟.通过求解雷诺时均N-S方程,并应用标准k-ε湍流模型来模拟泵内流动特性.首先用收敛的模拟结果与实验结果进行对比,将模型进一步修正,然后进行其他工况下的模拟.修正后的模型以及本文模拟的结果很好的反映了多相泵内流体流动的特点,同时利用该模型还可以进行各种工况下的性能预测以及多相泵的叶片翼型的优化.为今后新泵的设计提供了一种经济实用的方法.

Experimental Study and Numerical Simulation on a New Generation Helico-axial Multiphase Pump

This paper aims at presenting some research underway at China University of Petroleum(Beijing)both in experimental study and numerical simulations. After an extensive check on the multiphase loop to investigate its hydraulic and mechanical behavior under different working conditions, a new generation helico-axial MPP was tested. Performance test results showed that the MPP had the flexibility to handle wide range of flow rates, both steady-state and slug flows. Some factors, such as rotation speed, inlet suction pressure and gas void fraction(GVF)etc, had great influence on its performance. Test results showed that rising the rotation speed and suction pressure could better its performance, pressure boost improved, high efficiency zone expanding and the flow rate corresponding to the optimum working condition largened. The pump worked unstable as GVF increased to a certain extent and slip occurred between two phases in the pump, creating surging and gas lock at a high GVF. Also the mixer installed upstream played a vital role on its performance, improving the inlet flow condition, expanding the flexibility of the MPP. In order to improve the understanding of the flow field inside the pump, a Computational Fluid Dynamics(CFD)model has been developed. The commercial CFD code Fluent 6. 2 is used to carry out the flow simulations. The mean flow and turbulence were characteristics computed by solving the Reynolds averaged Navier-Stokes equations combined with the standard k-ε turbulence model. After the transient computational results had been obtained for a sufficiently long time period, the model was verified by comparing the transient computational results with experimental results. Good agreement between experiment and computations was obtained. Flow analysis reveals the distribution of velocities, pressures and volume fractions for all phases inside the MPP, which improves our understanding of the process. The computational model and results discussed in this paper would be useful for understanding the flow process and characteristics inside the pump, and also can provide a prediction method of MPP performance under any working condition and a cost effective method of shape optimization for future MPP designing.