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 relating to internal combustion turbines.
| Identifier | ExFiles\Box 147\2\ scan0193 | |
| Date | 25th July 1935 | |
| PATENT SPECIFICATION Application Date: July 25, 1935. No. 21107/35. 461,887 Complete Specification Left: July 24, 1936. Complete Specification Accepted: Feb. 25, 1937. PROVISIONAL SPECIFICATION Improvements relating to Internal Combustion Turbines I, FRANK WHITTLE, Flight Lieutenant R.A.F., of "Blackamoors", Harston Road, Trumpington, Cambridgeshire, British Subject, do hereby declare the 5 nature of this invention to be as follows:— This invention relates to that type of internal combustion turbine in which a constant pressure cycle is employed, and 10 in which the compression is performed wholly or in part by a centrifugal compressor and the expansion takes place wholly or in part through a turbine or turbines. 15 The object of this invention is to provide an improved prime mover of this type, and one which is deemed particularly suitable for aircraft. According to the invention an internal 20 combustion turbine consists primarily of one or more centrifugal compressors, one or more combustion chambers, and one or more turbine wheels, and such auxiliary apparatus as may be necessary. A con- 25 stant pressure thermal cycle is employed, and the working fluid flows continuously through the engine. There are many prior proposals of a similar nature, but all turbines of this 30 type have hitherto been condemned on the ground that if the working fluid is to engage the turbine buckets at a temperature which they can withstand continuously, then the efficiencies of turbines and centri- 35 fugal compressors are such that very little power is available for useful work when the power necessary to drive the compressor is subtracted from that realized at the turbine shaft. 40 Though this argument loses some of its force when considering a gas turbine suitable for operation at high altitudes, nevertheless real success depends upon a considerable improvement in the 45 efficiencies of both the centrifugal compressor and of the turbine, and also in the successful production of turbine buckets which are either cooled, or made of materials which have all the necessary 50 mechanical properties at very high temperatures. It is believed that the great improvements in materials and methods of cooling which have taken place in the development of exhaust valves for high duty aero 55 engines have considerably reduced the turbine bucket difficulty. The efficiency of both turbines and compressors depends upon the ratio of the losses which occur to the energy conver- 60 sion which they produce. These losses consist principally of (a) Fluid friction losses (b) Shock losses (c) Bearing friction. 65 Amongst other things, the fluid friction losses depend upon the area of internal surfaces swept by the working fluid, and it therefore follows that an increase of mass flow without any corresponding in- 70 crease of swept surfaces will reduce the proportion of loss due to this cause. Shock losses can be kept down chiefly by careful design, but it is believed that the proportion of this loss will also be 75 diminished if the mass flow is increased without any corresponding increase in size. As bearing friction is independent of the mass flow, it is obvious that the pro- 80 portion of this loss will decrease with increase of mass of flow. It is therefore the chief purpose of this invention to provide a gas turbine in which the mass flow of working fluid is far greater in pro- 85 portion to the size of the components than has ever previously been contemplated. For this reason it is an essential feature of this invention that the centrifugal compressor or compressors are of the type in 90 which an intake is provided on each side of the impeller casing, and it is considered very desirable that the compressor (or compressors) employed should be of the type described in co-pending applica- 95 tion No. 14285/35, that is to say, it has air intakes on both sides of the impeller casing: it also has an impeller with a large number of webbed and ribbed radial blades, and preferably also two rings of 100 intake guide blades (to permit of the employment of a large annular intake without any increase in shock at intake, and hence to permit of a further increase of capacity in proportion to size). 105 It also has a compound diffuser arrange- [Price 1/-] | ||