TY - RPRT A1 - Räbiger, Klaus A1 - Ward, John A1 - Maksoud, T.M.A. T1 - Development of a finite volume model for the compressible gap flow inside a screw pump N2 - Screw pumps are widely used in conditions of operation, where a constant flow rate and low pulsation are desirable. The type of screw pump, whose gaps are theoretically investigated in this paper, is a twin screw pump, which is used for multiphase operations. Due to the lack of knowledge concerning the pumping behaviour at very high gas volume fractions up to 100 %, the compressible gap flow inside a screw pump has to be investigated with techniques such as computational fluid dynamics more accurately. The development of a finite volume model for the compressible flow in each gap allows a prediction of the thermodynamic behaviour and of the inner leakage flow rate and thus, the effective flow rate of the pump. The resulting pressure and temperature distributions will enhance the understanding of the pump operation. T3 - Sonderdruck / Schriftenreihe der Georg-Simon-Ohm-Hochschule, Nürnberg - 30 Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:92-opus4-3481 ER - TY - RPRT A1 - Räbiger, Klaus A1 - Ward, John A1 - Maksoud, T.M.A. T1 - Heat transfer model for the simulation of spindle heating and expansion inside a multiphase screw pump N2 - The multiphase application of screw pumps, especially at high pressures and gas volume fractions implicates thermal loads for the solid components of the pump. For the evaluation of these loads and their consequences, a finite volume heat transfer model for the screws, as the main parts of a screw pump, was developed to describe and simulate the transient and 3-dimensional heat transfer process. The time-dependent heat transfer is mainly influenced by convection and thus by the rotational speed of the screws and by the tempera-ture distribution of the multiphase fluid along the screw surface. T3 - Sonderdruck / Schriftenreihe der Georg-Simon-Ohm-Hochschule, Nürnberg - 33 Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:92-opus4-3473 ER - TY - RPRT A1 - Räbiger, Klaus A1 - Maksoud, T.M.A. A1 - Ward, John T1 - Thermo- and fluid dynamic model of a multiphase screw pump, operating at very high gas volume fractions N2 - To describe the performance as well as the thermodynamic behaviour of a multiphase screw pump, also operating at very high gas volume fractions up to 100 %, a new thermo- and fluid dynamic model was developed. The model, which will be presented in this paper, takes the time-dependent gas-liquid heat transfer, the compressibility and acceleration effects of the multiphase gap flow as well as the possibility of critical flow conditions into account. For the simulation of the mutual phase heat transfer, the solution of the gap flow conservation equations and the optimisation of the gap inflow velocity, different numerical techniques were used. The model as such gives important information of the pressure and the temperature distribution, the multiphase leakage flows through the chamber connecting gaps as well as the effective flow rate or the volumetric efficiency of the pump near the conveyance break-off at very high gas volume fractions. T3 - Sonderdruck / Schriftenreihe der Georg-Simon-Ohm-Hochschule, Nürnberg - 35 Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:92-opus4-3462 ER -