Metodologia inversa quase-tridimensional para o projeto de máquinas de fluxo hidráulicas

Abstract

Inverse methodologies continue to be important computational tools for the design of flow machines, despite the sophisticated methods currently available for the analysis of viscous three-dimensional flows. A Quasi-Three-Dimensional methodology based on the interdependent solution of two inverse problems is described in this work: the through-flow problem and the blade-to-blade problem. The developments continue the research by Santos et al. (2012) and Barbosa (2018). The solution to the through-flow problem – referring to the work of Santos et al. (2012) - provides the shape of the mean flow surface and the results of the streamlines, to meet a given hydraulic momentum distribution. The inverse blade-to-blade problem – referring to the developments of Barbosa (2018) – provides the geometry of the blades, given a finite number of blades, on surfaces of revolution whose generatrices are the streamlines resulting from the through-flow problem. Until then, the effects of thickness and blocking were disregarded. In this work, a methodology for including thickness distributions along the blades is described. The thickness effect is analyzed through the direct solution of the blade-to-blade problem (now considering profiles) using the panel method based on linear vortex distributions. The corresponding blocking factors are calculated, and the results feed the input of a new solution of the through-flow problem. Thus, the through-flow problem and blade to-blade become coupled. The geometry is recalculated, now considering the effect of thickness and blocking. Furthermore, the effects of a) hydraulic momentum distribution; b) finite number of blades; c) thickness; d) blocking; e) combination of b), c) and d); and f) profile stacking line on the geometry of the blades and their hydrodynamic loads are analyzed.