The paper presents the results of an experimental and theoretical study of the gas flow structure in a Laval nozzle. Specific flow features were identified in the near-wall region of the supersonic section of the nozzle, leading to significantly lower pressure values in the throat section (approximately two times lower than those calculated using standard methods) compared with the calculated results. This discrepancy, revealed through simulations performed in the ANSYS Fluent software package, is caused by differences between the flow parameters in the core region and those in the boundary layer near the wall. Standard calculation methods are generally based on experimental data and semi-empirical correlations, which results in dependencies that do not adequately reflect the complex flow structure. At the same time, due to wall friction and gas vortices within the nozzle, the distribution of parameters across the cross-section is highly nonuniform. The paper compares standard calculation methods, numerical simulations, and experimental data. It is shown that simulations performed using ANSYS Fluent made it possible to account for the spatial features of the flow and to evaluate parameters not only along the flow axis, providing better agreement with experimental results than standard methods.

EDN UQVLJI