GB822037A - Jet propulsion engines - Google Patents

Abstract

822,037. Generating combustion products under pressure. NATIONAL RESEARCH COUNCIL. May 10, 1956 [July 21, 1955 ; Feb. 9, 1956], No. 14592/56. Class 51 (1). A jet propulsion engine comprises a main combustion stage and a reheat combustion stage, the latter comprising a flame stabilizing device and means for introducing fuel upstream thereof, means also being provided for projecting streams of fluid from the downstream edge of the flame stabilizing device into the path of the combustion gas stream flowing past the stabilizer so as to prevent the onset of screech combustion. The fluid may be fuel or water or a gas such as air or it may be a portion of the combustion gases themselves. In Fig. 2 the flame stabilizer 15 is of conical form and a tubular ring 17 having a series of outlets 19 is disposed within the downstream edge thereof, fluid supplied through the pipe 18 issuing through the outlets 19 in the form of a conical spray 20. If the fluid is water the outlets in the ring 17 are disposed so that the water is directed into the centre of the conical flame stabilizer, the resulting steam issuing past the downstream edge of the stabilizer being effective to reduce screech. The tubular ring may be disposed on the outer surface of the conical stabilizer at the downstream edge. In the case of an annular V-section flame stabilizer the fluid manifolds may be disposed either on the inner or outer surfaces thereof. When the fluid is combustion gas, a vane 31 may be associated with the stabilizer 30 so that the velocity of gases flowing through the convergent space therebetween is increased, the stream of increased velocity issuing at A into the main gas flow. A flame stabilizer comprising six V-section troughs is shown in Fig. 7, a vane 36 being associated with one surface of each trough 34. In the case of a flame stabilizer of annular V-section form a cylindrical ring may be associated with either the inner or the outer surface thereof to provide an annular passage of converging form. Where two annular flame stabilizers of V-section are provided they may be disposed so that the annular convergent space between the two stabilizers acts to produce a stream of combustion gases flowing past the downstream edges of the stabilizers. Similarly the convergent spaces between pairs of straight, parallel flame stabilizers may be so used.