Liquid fuel rocket engine having adjustable nozzle throat section

Abstract

A liquid fuel rocket engine comprises a housing having an outer annular wall and an inner annular wall which define therebetween a combustion chamber of substantially uniform cross section and leading to a converging wall section and a nozzle throat of narrow dimension. Means are provided to vary the nozzle throat section during operation of the engine in order to obtain better performance operation of the engine. The means for varying the dimension comprises a thermal arrangement whereby the cooling of the housing walls are divided up into sectors through which a propellant component is circulated. The temperature of the circulated component and the quantity of component which is circulated are advantageously controlled in order to vary the thermal expansion of the various sector portions and thereby change the axial and radial position of the walls defining the nozzle throat section. This is done either by controlling the propellant component which is directed through each of four separate sectors of the housing parts making up the outer and inner walls of the housing or by controlling only the cooling rate of the outer walls to vary the boundaries of the nozzle throat. The control is accomplished by a globe valve member which is pivoted in order to vary the distribution flow of a propellant component through each of a plurality of flow paths for regulating the cooling of the various portions of the inner and outer housing walls. In addition a mechanical means may be provided to actually vary the position of one or both of the outer and inner walls so as to control the nozzle throat section.