CONSTRICTOR FLOW-ANALYSIS OF A MEDIUM POWER HYDROGEN ARCJET

In a thermal arcjet the main heating of the propellant takes place in the constrictor. To gain more insight into arcjet operation and to obt ain experimental data on the shape, size, and stability of the arc cha nnel inside the constrictor, a modified arcjet thruster was built. Thr ough a window in the nozzle throat the discharge channel in the constr ictor was observed. With a fast CCD camera, images of the arc were tak en, and using image processing methods a hydrogen arc was analyzed. Th e camera system was calibrated to measure absolute intensities. Thus, it was possible to determine the two-dimensional temperature profiles from electron continuum and from the line intensity ratio of the H(alp ha) and the H(beta) line. In the second section, an analytical method to calculate the flow conditions inside the constrictor is described. The first version of the model is developed for hydrogen as propellant . The calculation results are compared with measurements.