Coupled pressure based CFD solver for turbomachinery flows: overview of applications

Authors

Luca Mangani - Hochschule Luzern
Ernesto Casartelli - Hochschule Luzern
Marwan Darwish - American University of Beirut

Abstract

CFD has become an indispensable tool for the design and analysis of modern turbomachinery equipment. Commercial codes usually play a major role for these processes, offering dedicated pre- and postprocessing features, but also advanced solver technology, in order to ease the approach to CFD for the development engineers. In the last decade both academic and industrial institutions have started to explore alternatives in order to achieve more flexibility in the development and implementation of new specific models and more resources in large-scale deployment of CFD procedures, especially in unsteady and transient processes as well as automatic optimization procedures. In this paper, the capabilities of a new, general-purpose coupled pressure-based CFD solver are presented. The code is developed based on the C++ object-oriented language, the discretization method employed is a finite volume cell centered approach. Pressure-based algorithms for the pressure-velocity coupling were adopted for compressible and incompressible flows with a series of new implicit developments specific for turbomachinery (mixing plane, boundary conditions, treatment of source terms), to improve convergence speed and robustness. Beside a large range of state-of-the-art turbomachinery specific features, new models like k-epsilon with enhanced wall functions and a novel all-Mach real-gas model are implemented in a coupled way. The present publication shows an overview of the developed code and models, and a series of turbomachinery applications, ranging from subsonic to transonic internal flow, turbine cooling and conjugate heat transfer as well as transient computations in hydraulic machines.