Application of Method of Characteristics in Three Dimensional Supersonic Flows of Nozzles

The purpose of the present investigation is the development of an accurate numerical method and the associate computer program for the calculation of steady three dimensional adiabatic flows in supersonic rocket engine nozzles. The fluid is assumed to be an inviscid perfect gas and the flow is assumed to be shock free. The governing equations for this flow model consist of the continuity equation, the momentum equations, and the speed of sound equation. The steady three dimensional supersonic flows is computed using a pentahedral bicharacteristic method. An inverse marching method based on the network of wavelines and the pathline is employed. The spline surface fit is used in the iteration procedure to evaluate the location of the unknown point in the new reference plane and its flow properties. The numerical algorithms are based on the modified Euler predictor-corrector integration scheme. A typical nozzle divergent section is used for the flow computation validation. Through the numerical calculations, the flow parameter distributions, such as Mach number, pressure, density, velocity, and flow angles of the nozzle are obtained. The results obtained for the typical nozzle with the computer program are acceptably accurate. It can be concluded that the method can be used in flow analysis of rocket nozzles.