Compressible Boundary Layer Effects on Performance of Low Thrust Nozzle

Rocket Thrusters are used for various purposes including main stage control and attitude control. The function of an attitude control thruster is mainly to provide accurate attitude correction for a space vehicle / payload / satellite during its orbit manoeuvre or orbit insertion. It is a known fact that it will be operated multiple times and during each time of operation, it should deliver accurate thrust for vehicle correction when commanded. If an attitude control thruster is a low thrust nozzle, effect of high viscous losses is felt on nozzle expansion ratio, further affecting nozzle’s thrust & specific impulse. Compressible boundary layer analysis is carried out for low thrust nozzle in MATLAB assuming inviscid isentropic core surrounded by laminar boundary layer at wall in the nozzle divergent portion. The code is also validated against Rothe nozzle experimental results as well as DSMC & extended CFD results. Bird’s break down parameter is computed for the conical nozzle assuming both Inviscid and viscid flow conditions, which will be useful to evaluate the validity of computations