Supersonic hydrogen combustion with a short thrust nozzle

Abstract

A shock tunnel was used to investigate the thrust produced by supersonic combustion of hydrogen in a simple, two-dimensional combustion chamber-exhaust nozzle combination, at stagnation enthalpies up to 15 MJ kg −1. The experiments demonstrated that one-dimensional flow concepts were not adequate to predict the thrust level, and that two-dimensional effects must be taken into account. An analysis was developed which allowed the internal thrust increment of the two-dimensional nozzle to be compared with that of an equivalent one-dimensional one. It was found that, up to combustor static temperatures of 2000K, measured thrust increments were approximately half of the value for premixed equilibrium flow through the equivalent one-dimensional nozzle. Ignition occurred at approximately 1000K, and values of internal specific impulse rose above 1000 s just above this temperature, but fell to 500 s as temperatures rose above 2000K.