On indirect noise in multicomponent nozzle flows

摘要: A one-dimensional, unsteady nozzle flow is modelled to identify the sources of indirect noise in multi-component gases. First, from non-equilibrium thermodynamics relations, it shown that a compositional inhomogeneity advected an accelerating source sound induced by inhomogeneities mixture (i) chemical potentials and (ii) specific heat capacities. Second, acoustic, entropy linear perturbations evolve independently each other they become coupled through mean-flow gradients and/or at boundaries. Third, equations are cast invariant formulation mathematical solution found asymptotic expansion path-ordered integrals with infinite radius convergence. Finally, transfer functions calculated for supersonic finite spatial extent perturbed methane-air inhomogeneity. The proposed framework will help quantify nozzles relevance, example, aeronautical gas turbines.