| A 3-inch vertical closed liquid flow loop is built to test a 14-stage radial type electrical submersible pump (ESP) under viscous fluid flow conditions. A pipe-in-pipe heat exchanger is constructed to control the temperature and a pipe viscometer is employed to measure the fluid viscosity. A mineral oil is used as the working fluid. The ESP hydraulic heads are measured with oil viscosities of 37, 54, 74, 80, 98, and 107 cP at 2,400 rpm and with oil viscosities of 45, 54, 67, 74, and 82 cP at 3,500 rpm. The ESP head curves deteriorate with fluid viscosity increase.;Three-dimensional computational fluid dynamics (CFD) is implemented to study the viscous influence on ESP and help flow loop design. CFD simulations are carried out to obtain the ESP head curves at 1, 3, 5, 10, 30, 50, 100, 300, 500, and 1,000 cP. Compared with experimental measurements, the head predicted by CFD with viscous fluid is higher.;A mechanistic model is developed to predict ESP hydraulic head based on Euler's equation. A flow rate at the best match point (BMP) is utilized to find the effective velocity at the ESP impeller outlet so that the recirculation is considered. Friction losses and the losses due to flow direction change are also taken into account. The mechanistic model predictions of ESP head are validated with two types of ESP, one is a radial type tested in this study and the other one is a mixed type. The prediction errors are within +/-10%. |
