From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Patent specification for improvements in aircraft propulsion, specifically relating to a double thermal cycle engine.
| Identifier | ExFiles\Box 147\2\ scan0189 | |
| Date | 4th March 1936 | |
| PATENT SPECIFICATION Application Date: March 4, 1936. No. 6505/36. 471,368 Complete Specification Left: Feb. 19, 1937. Complete Specification Accepted: Sept. 3, 1937. PROVISIONAL SPECIFICATION Improvements relating to the Propulsion of Aircraft I, FRANK WHITTLE, of Blackamoors, Harston Road, Trumpington, Cambridgeshire, British Subject, do hereby declare the nature of this invention to be as 5 follows:— This invention refers to apparatus, the function of which is to provide a supply of working fluid at a pressure above that of the atmosphere for the purpose of 10 doing useful work in its subsequent expansion, as for example in a turbine, or through the propelling jet of an aircraft propelled by fluid reaction, or through the reaction jets of an airscrew acting as 15 a reaction turbine in the manner of a "Barker's Mill". A known form of such an apparatus is one in which a centrifugal compressor compresses air into a combustion cham- 20 ber wherein it is heated at a constant pressure by the burning of a suitable fuel, the heated products of combustion then expanding through the nozzles of a turbine, the function of which is to drive 25 the compressor and necessary auxiliaries. The fluid leaving the turbine, being capable of further expansion, forms a supply of working fluid for the production of power in various ways, such as 30 those cited above. The purpose of this invention is to provide improved apparatus for the same purposes. The primary object is to provide a great mass flow of the working 35 fluid as possible in proportion to the size of the mechanisms employed, in order that certain losses, such as fluid friction loss, shall be kept as low as possible in all components. 40 The high mass flow is particularly desirable in the case of the propulsion of aircraft by fluid reaction, in order that the jet velocity shall be as low as possible for a given thrust. 45 According to the invention, a double thermal cycle is employed, the whole of the working fluid passing through a "lower cycle", and a portion of the working fluid passing through a "higher 50 cycle". The lower cycle consists of a compression to an "intermediate pressure" and an expansion back to atmospheric pres- sure after expansion at the intermediate 55 pressure as a result of a portion of the fluid having passed through the higher cycle. The higher cycle consists of a compression from the intermediate pressure, a 60 heating by the combustion of a suitable fuel and an expansion back to the intermediate pressure. The work of expansion in the higher cycle provides the power for the whole 65 of the compression and for the drive of necessary auxiliaries. The work of expansion of the lower cycle represents the energy content available for any suitable purpose. 70 The mechanisms by which the various operations are performed may be of any suitable type and may incorporate known features to improve the efficiency or power, such as heat interchangers, or 75 additional fuel combustion at the intermediate pressure, and/or at suitable points in the expansion of the higher cycle. Describing the invention in one form deemed suitable for the propulsion of air- 80 craft either by direct fluid reaction, or by gas turbines driving airscrews, or by airscrews driven by reactive jets at their tips; air slightly precompressed by virtue of the forward speed of the aircraft is 85 compressed to the intermediate pressure by a suitable mechanical compressor. From this compressor the air passes into an intermediate pressure chamber. 90 From the intermediate pressure chamber a portion of the air is compressed in a second compressor; the air leaving the second compressor passes through a heat interchanger and into a combustion 95 chamber where it is heated by the constant combustion of a suitable fuel. From the combustion chamber the heated products of combustion expand through one or more turbine wheels coupled directly 100 or geared to the compressors. The exhaust from the turbine or turbines passes through the heat interchanger to give up some of its heat to the compressed air leaving the second compressor, and thence 105 back into the intermediate pressure chamber to mix with the remainder of the [Price 1/-] | ||