Master thesis and internship[BR]- Master's thesis : Numerical study of the impact of nozzle shape on underexpanded jet - wall interaction[BR]- Integration Internship

Abstract

A numerical investigation concerning axisymmetric underexpanded turbulent flow issuing from a convergent-divergent nozzle is carried out by means of Reynolds averaged Navier-Stokes (RANS) equations and is contained in this work. The numerical computations are performed making use of the in-built axisymmetric solver of the open-source CFD software SU2 and regard the outflow expansion in case of jet release in a quiescent environment and in case of jet impingement on a flat plate. By doing so, this work proposes to investigate if the free-flow and impinging flow structures are sensitive to the shape of the nozzle used to accelerate the fluid, and if yes, to which extent. This is accomplished by considering three different nozzles: one contoured and two conical nozzles with different lengths. To cover a wider range of configuration, the nozzle-pressure-ratio (NPR) and the nozzle-to-plate distance are also varied. From the investigation of the flow field, it is found that the intensity of the shocks contained in both the core region and the impinging region of the jet are affected by the nozzle geometry, while the evolution of the radial wall-jet generated by the jet impingement is instead found to have rather small sensitivity. Validation and verification of the code is also performed in advance by replicating real experimental tests and comparing the obtained results with other numerical simulations found in literature.