Friction losses in fluid filled rotating assembly

Abstract

Consulta en la Biblioteca ETSI Industriales (8850)

[EN] Offshore platform, mining, Oil and Gas, power generation and water resources are some of the application fields for a deep submersible pumps. Each time are in deeper and challenging locations. Motor technology is being updated with the requirements for subsea drives. Due to this, compact motors with high capacities assembled with deep submersible pumps are the greatest option in order to work under these conditions. However, the increased price of energy, power demand and the growth of environmental problems have imposed the improvement of efficiency for this kind of machines. In this thesis, a systematic numerical calculations research using CFD code such as CFX has been carried out. An extensive research in the field was effected, finding just a few studies in the topic. Therefore, an initial theoretical approach was introduce continuing with an overall of the main problems at the fluid which is running inside the motor is analyzed. A comparison between experimental values and numerical results is done in order to compare the accuracy of the results. The best model resulting from the validation was used to investigated the effect of the friction losses inside the motor. Several new stator geometries are proposed against the used by the current stator model. Comparison between roughness and smooth cases has been tested. The friction behavior of the flow is analyzed in detail and compared with the original one. Dynamic viscosity, eddy viscosity, density and velocity are parameter considered in the research. Eddy viscosity and velocity show an influence on the friction losses. However, the influence of the velocity gradient is especially important in the development of the turbulence and hence the losses. An average reduction of up to 57.24% of friction losses in several cases it has been achieved for the smooth case. It has been found a pattern followed by the velocity gradient which explain the flow behavior. The losses inside the rotor depends strongly on the stator geometry and the roughness of the surfaces where it is flowing.