bachelorThesis
Simulação numérica do escoamento bifásico deb líquido-gás em um rotor plano
Fecha
2018-12-13Registro en:
KASHIWAKURA, Lucas Yuji. Simulação numérica do escoamento bifásico deb líquido-gás em um rotor plano. 2018. 110 f. Trabalho de Conclusão de Curso (Graduação em Engenharia Mecânica) - Universidade Tecnológica Federal do Paraná, Curitiba, 2018.
Autor
Kashiwakura, Lucas Yuji
Resumen
Liquid-gas to flows are usually found into oil & gas and nuclear industries. In oil & gas industry, centrifugal pumps are used as one of the artificial elevation techniques, having as a challenge the implementation onto the oil production in deep-water. It is already known, that the presence of gas inside the pump, can cause a drastic reduction in the equipment's performance, and for critical cases it can even block the flow inside the rotor, which is named as gas locking. From these scenarios arises the motivation to develop a numerical study to analyze the liquid-gas flow inside the rotor. The modelling of this high-complexity problem was adopted an Euler-Euler model for two-phase flow, as a representation of the liquid-gas flow, considering its interfacial effects, as bubble's break and coalescence phenomenon, and also adding the polidisperse model of multiple dimensional groups (MUSIG) in its analysis. The numerical solution is acquired through the usage of Computational Fluid Dynamics program - Ansys® CFX®, which uses an element-based Finite Volume Method. A simplified geometry of a plane radial rotor is used to obtain the performance curves for a water-air flow for gas mass flow of 0,06; 0,12 and 0,18 kg/h, the rotation velocities between 200 and 500 rpm and liquid flow normalized by the design flow varying between 0,2 and 2,6. The adopted numeric model was able to predict the rotor performance drop, in which stand out the results for low mass flow. A tendency to overestimating the gain pressure values after the inversion point could be observed. In spite of it, the model was able to correctly predict the curve’s inversion region, even if the results present large values deviations. Qualitatively, it is possible to affirm that the two-phase flow dynamic was successfully reproduce, the numeric images were validated with the experimental images obtained by Stel (2018). Bubble breakage and coalescence effects were observed and also the increasing of the bubble breakage owing to the rotation velocities. Ultimately, this work contributes with the literature through the detailed numeric results analysis, in which were associated the performance curves e flow dynamic inside the rotor. And also by demonstrating the capacity of the Two-Fluid Model in reproduce a two-phase flow and its particularities.