| dc.description.abstract | Canned motor pump (CMP), as one kind of sealless pump, has been utilized in industry for many years to handle hazards or toxic product and to minimize leakage to the environment. In a canned motor pump, the impeller is directly mounted on the motor shaft and the pump bearing is usually cooled and lubricated by the pump process liquid. To be employed in oil field, CMP must have the ability to work under multiphase flow conditions, which is a common situation for artificial lift. In this study, we studied the performance and reliability of a vertical CMP from Curtiss-Wright Corporation in oil and air two-phase flow condition. Part of the process liquid in this CMP is recirculated to cool the motor and lubricate the thrust bearing. The pump went through varying flow rates and different gas volume fractions (GVFs). In the test, three important parameters, including the hydraulic performance, the pump inside temperature and the thrust bearing load were monitored, recorded and analyzed. The CMP has a second recirculation loop inside the pump to lubricate the thrust bearing as well as to cool down the motor windings. Since the second loop will lower the pump hydraulic performance, CFD simulation was carried out to analyze the effect of different flow rates and GVFs on the heat transfer in the recirculation channel. The simulation results show that reducing the current recirculation flow rate by 50% will only increase the recirculation outer wall temperature about 1 K. When 20% GVF air is presented in the recirculation flow, the wall temperature shows a maximum of 5 K increase.
The CMP has both pump-out-vanes (POV) and ribs on pump casing to control the axial thrust. The CFD results show that the current vane and rib geometries are already optimized and the axial thrust is always controlled at a low level at different working condition. The POV increases the pump power consumption and lowers pump overall efficiency. | en |
