Patent GB-1035015-A (GB)
Title: Improvements in or relating to jet propulsion power plant
Inventor: PALFREYMAN JACK
IPC: F02K7/18
Filed: 1965-05-11
Abstract: 1,035,015. Jet propulsion plant combustion equipment. ROLLS-ROYCE Ltd. May 11, 1965, No. 19936/65. Headings F1J and F1L. Combustion equipment for a jet propulsion power plant comprises an air flow duct divergent in a downstream direction, a plurality of flow dividing members spaced apart across the duct and extending in a downstream direction, adjacent members diverging with respect to each other in a downstream direction to define therebetween a plurality of diffuser ducts in parallel, and means for supplying fuel to said flow duct, combustion of the fuel taking place in air which has passed through the diffuser ducts. In the embodiment described, a diffuser duct assembly 15 located in a divergent portion of the upstream end of the flow duct comprises a plurality of circumferentally and axially extending flow dividing members 16 spaced at equal radial intervals, each diverging in a downstream direction with respect to each immediately adjacent member at an angle of between 6 degrees and 7 degrees taken in an axial plane. Each member 16 other than the radially outermost member has a solid upstream portion 17 and a hollow downstream portion 18 separated by a small gap 19. The interior of each downstream portion 18 communicates with the flow duct through a plurality of axially extending slots 20 spaced apart at equal circumferential intervals in each wall of the member 16 adjacent its trailing edge. In one application, the combustion products from a first combustion equipment e.g. a rocket motor which burns kerosene fuel using liquid oxygen as oxidant, pass into a second combustion equipment, which is of the type described, by way of a plurality of manifolds 21 (only one of which is shown) extending radially across the upstream end of the flow duct. Each manifold 21 is formed with a rearwardly facing inlet scoop 22 which communicates with an annular outlet passage 23 leading from the first combustion equipment, and communicates with the hollow interiors of the downstream portion 18 of each member 16 through axially extending slots (not shown) in the circumferentially facing side walls of the manifold. The combustion products thus pass through the manifolds 21 into the flow duct at the downstream end of the diffuser duct assembly 15 by way of the slots 20. A plurality of equiangularly spaced apart hollow struts 24 extends radially across the upstream end of the flow duct, each strut 24 being disposed immediately downstream of and aligned with a manifold 21. Nozzles 25 are provided in the trailing edge of each strut 24 and means (not shown) are provided for supplying fuel (e.g. kerosene), additional to that supplied to the first combustion equipment, to the struts 24. Means (not shown) are provided in the flow duct downstream of the struts 24 for igniting fuel injected by the nozzles 25. Where excess fuel is supplied to the first combustion equipment in order to keep the temperature therein as low as possible, the unburnt excess fuel entering the second combustion equipment may be sufficient to render a separate fuel supply to the latter unnecessary. The portion of the flow duct downstream of the struts 24 forms a combustion chamber, the walls of which are formed by inner and outer double-walled lining members-converging to a throat and then diverging, so as to form a convergent-divergent exhaust nozzle. The inner lining member is carried by a bullet member, the axial position of which is adjustable so that the geometry and effective throat area of the nozzle may be varied. The innermost walls of the doublewalled lining members are porous and cooling air derived from the flow duct upstream of the diffuser duct assembly 15 flows into the combustion chamber through these walls to provide film cooling of the lining members.