Thermo-Hydraulic Model of a Twin-Screw Multiphase Pump

Abstract

The twin-screw multiphase pump has been studied as an alternative equipment to substitute the conventional system (fluid separation, liquid pumping and gas compression) in petroleum boosting. By “pumping” gas and liquid together, the multiphase pump could reduce production costs, particularly in deepwater activity. This paper presents a thermo-hydraulic model of a twin-screw multiphase pump developed to determine important parameters such as: volumetric efficiency, absorbed power, discharge conditions, heat transfer and pressure and temperature profiles. The continuous movement from suction to the discharge of pump chambers is divided in small discretive steps. This division allows the calculation of energy and mass balances for each screw chamber. At each step, it is possible to calculate mass and energy that enters and leaves one chamber. With this balance, pressure and temperature for the next step can be calculated. Differently from previous model, it considers not only water-air but also hydrocarbon mixtures (including petroleum heavy fractions) as working fluids. Besides, inclusion of screw rotation influence over peripheral backflow is not neglected as in previous models.

The structure optimisation of hydraulic mechanical screw pump

“…The relative sliding velocity and the frequency at which it occurs directly affect the friction-wear and fatigue wear of the screw-bushing pair. To facilitate the study of the relative sliding speed of the bushing, assuming that the movement of the screw in the bushing does not move in the axial direction (Nakashima et al, 2004). Therefore, the relative sliding can be simplified as a planar motion problem.…”

“…f Make the flow area coefficient and its equivalent curve. The size of the flow area directly affects the performance of single screw hydraulic machinery (Nakashima et al, 2004). The larger the overcurrent area, the more favourable the output performance.…”

The structure optimisation of hydraulic mechanical screw pump

“…The relative sliding velocity and the frequency at which it occurs directly affect the friction-wear and fatigue wear of the screw-bushing pair. To facilitate the study of the relative sliding speed of the bushing, assuming that the movement of the screw in the bushing does not move in the axial direction (Nakashima et al, 2004). Therefore, the relative sliding can be simplified as a planar motion problem.…”

“…f Make the flow area coefficient and its equivalent curve. The size of the flow area directly affects the performance of single screw hydraulic machinery (Nakashima et al, 2004). The larger the overcurrent area, the more favourable the output performance.…”

Theoretical and experimental analysis of a multiphase screw pump, handling gas–liquid mixtures with very high gas volume fractions

“…Several former investigations [1][2][3][4][5][6][7] showed already, that screw pumps present a promising method to meet the requirements on the pump performance and the reliability onshore and offshore. Nevertheless, there is still a demand on secure simulation tools for extreme operating conditions like very high gas volume fractions up to nearly 100%.…”