CFD simulation of a compressor blade for comparision and validation with XFOIL results

Abstract

A research in compressor performance and optimization is carried out. Parameters such as efficiency and operational range are intended to be optimized. In order to do that, the flow field is studied. As a beginning, a single compressor blade in a rectangular duct is studied. In this paper, several simulations are carried out with ANSYS. Flows with different velocities are tested. In the first place, flow with a low subsonic velocity is tested (Mach number lower than 0.3). In this case, incompressible flow can be assumed. As a result, some simplifications can be made and the problem is easier to set up and solve. In the second place, flow with high subsonic velocity is also tested (Mach number higher than 0.3). Now, a hypothesis about incompressible flow is not valid, since the flow could reach the speed of sound in some areas, and some compressible phenomena such as shock waves could appear. Therefore, these two problems will be treated in different ways. A mesh, which covers the whole domain, is created and different boundary conditions are applied in order to make the simulation as real as possible. For instance, velocity at the inlet or pressure at the outlet of the domain can be settled. Depending on the values chosen for those conditions, different solutions are calculated. Thus, it is really important to know which conditions are the best in order to achieve real solutions. These solutions are then compared with results obtained with XFOIL. They are presented in terms of the distribution of the pressure coefficient. The simulations done with this software in order to achieve these solutions are also explained in this paper. With these comparisons, the set up done can be proved and some parts or even the whole process can be validated. The results can be used in other areas such as structural or material analysis of these compressors, since the flow field gives information about the forces and stresses that the blade suffers. This paper can also serve as a starting point for more complex simulations within the compressor.