Fluid characteristic of multiphase fluid in annular space between pump barrel and plunger

The pump performance parameters, such as pump pressure, plunger friction and pump valve resistance, are fundamental parameters of optimal design of pump efficiency and sucker rod pumping system (SRPS). In this paper, considering the characteristic of geometrical nonlinear and rheology property of multiphase fluid, the pump performance parameters are studied. Firstly, a dynamics model of annular fluid flow is built. In the detail, a partial differential equation of annular fluid is established and a computing model of fluid pressure gradient is built. Secondly, the simulation models of plunger friction and hydraulic resistance of pump valve are built. Finally, a novel simulation method of fluid pressure in annular space is proposed with software ANSYS. In order to check up the correction of models proposed in this paper, the comparison curves of experiment and simulation results are given. Based on above model, the whole simulation model of plunger pump is simulated with Visual Basic 6.0. The results show that the fluid friction of pump plunger and instantaneous resistance of pump valve are nonlinear. The impact factors of pump performance parameters are analyzed, and their characteristic curves are given, which can help to optimize the pump motion parameters and pump structural.