GB856260A - A small closed cycle gas turbine - Google Patents

Abstract

856,260. Gas-turbine plant. NEEDHAM, R. W. Feb. 4, 1958, No. 136/58. Class 110 (3). In a closed cycle gas-turbine having a gaseous fluid or fluids flowing in contact with internal components of the engine or to flow between sections of the engine for reducing the operating temperatures of the components or to form a screen between hot and cooler sections of the engine or all these together, the major part of the gaseous fluid is conducted to a point in the plant where it receives further heat. The circulating gas that is argon with possibly small quantities of hydrogen and/or the inert gases enters a single stage centrifugal compressor at A. The gas is compressed and passed through diffusers B to a heat exchanger which is preferably located immediately below the engine. The heated gas enters a gas heater at C comprising a large number of small diameter tubes D. The tubes are made of hightemperature corrosion-resisting materials. The gas leaves the heater at E and passes by suitable pipes to the turbine volute F. The gas is led through a two-stage turbine K, L, and then passed through a diffusing volute M to the heat exchanger. After leaving the heat exchanger the gas passes back through a cooler to the inlet of the compressor A. The turbine casing is surrounded by a second casing which carries the turbine bearings. The turbine K drives the plant compressor and the turbine L the useful output shaft. A part of the air leaving the compressor is led through passages g in the second casing and used for bearing and disc cooling, casing pressurizing and turbinecasing insulation. This air passes through holes h to joint the circulating gas from the heat exchanger at C. The leak at the disc periphery effects some blade cooling. Some gas is also taken from the-compressor outlet to the main output gear-box N. Combustion air is compressed by a single-stage compressor P and passed through the pipes of an air preheater Q to grilled ceramic fuel-burners S. Some of this combustion air is passed through a space between the lining and casing of the gas heater and is then used to preheat the fuel. The combustion gases after passing over the tubes D, pass through the preheater Q to an exhaust at U. The turbine L also drives through a layshaft V two oil pumps. The engine may be broken down into a number of sub-assemblies α 1 -α 5 . The engine is controlled by regulating the fuel supply in accordance with the temperature of the combustion gases. Another form of control is a by-pass valve in the circuit between the compressor outlet and compressor or cooler inlet. The plant may also be pressurecontrolled.