Abstract
Due to the advantages of heat and wear resistance, all-metal screw pumps have been commonly applied in field tests in recent years. In this work, the methods of thermodynamic and computational fluid dynamic were applied to analyze the effects of temperature and viscosity on clearance between rotor and stator of the all-metal screw pump. The clearance between stator and rotor of the all-metal screw pump has been optimized. Different model machines of the all-metal screw pump with different clearances have been manufactured, and numerous tests have been carried out in laboratory and fields in order to analyze the effects of rotational speed and viscosity of medium on the characteristics of the all-metal screw pumps. Results show that the performance of all-metal screw pumps is compared with that of rubber screw pumps. Results show that the medium viscosity and rotational speeds have significance effect on pump efficiency. An increase in the pump efficiency could be achieved with an increase in the rotational speed. However, compared with the rotational speeds, the viscosity of medium shows a more severe influence on the pump efficiency. Characteristics of the newly developed all-metal screw pumps could satisfy design requirements. Characteristics of the all-metal screw pumps consistent with the results of laboratory experiments, and operation processes are smooth and reliable. This article provides a theoretical guidance to the promotion and application of this technology.DOI: http://dx.doi.org/10.5755/j01.mech.23.5.15387
Highlights
Since Moineau developed the single-screw hydraulic machinery theory in the 1930 s, single-screw hydraulic machinery pumps and screw motors have been widely applied in the petroleum and chemical areas [1,2]
This paper presents the clearance optimization of all-metal screw pump with considerations of high temperature and fluid viscosity
Data processing The volumetric efficiency of the all-metal screw pump is calculated by Eq (1), and the relationships between the pump efficiency and head under different media and rotational speeds were drawn
Summary
Since Moineau developed the single-screw hydraulic machinery theory in the 1930 s, single-screw hydraulic machinery pumps and screw motors have been widely applied in the petroleum and chemical areas [1,2]. Conventional screw pumps consist of rubber bushings and metal rotors, which are mainly applied in cold production and lifting of heavy oils or other viscous liquids [3]. Since conventional rubber screw pumps cannot tolerate more than 160°C, they are not suitable for thermal recovery wells For these kinds of oil wells, TOTAL and PCM companies used the all-metal screw pumps lift method in two wells in the Joslyn oilfield in Alberta for field tests. Recent research studies on the optimization on geometry parameters of the screw pumps are mainly focused on conventional single screw pumps, and taking the actual working conditions into considerations, parameters are modified based on the empirical formula and field trials. Based on recent research status at home and abroad, optimization theories and methods on the clearance between the rotor and the stator of all-metal screw pumps are few. The standard testing method is used to analyze the operating characteristics of all-metal screw pumps, and the testing results can provide guidance for the applications of all-metal screw pumps in the field sites
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