Patent GB-855136-A (GB)
Title: A multi-stage gas turbine plant
IPC: F02C3/34
Filed: 1957-05-03
Abstract: 855,136. Gas turbine plant. SONNEFELD, G. May 3, 1957 [May 7, 1956 (2)], No. 14253/57. Class 110 (3). A gas turbine plant in which the total available heat drop is divided into several stages and the heat drop, with the exception of the first stage, is utilized in turbines whilst the heat drop of the first stage is utilized for increasing the pressure and temperature of a part of the gas extracted from an intermediate stage of the turbine to the pressure and temperature at the inlet of the turbine, has the pressure and temperature of the gas increased in an equalizing nozzle which has, in the direction of flow, the following sections: (a) an inlet nozzle section containing a separate inlet nozzle for each gas stream to impart to the gas stream of lower pressure super-critical velocity and to impart to the gas stream of higher pressure substantially the same velocity; (b) a pressure-equalizing section in which the cross-section of the equalizing nozzle decreases in the direction of flow so that a pressure equalization transversely of the direction of flow is produced while the velocity of the gas stream remains unchanged; (c) a convergent diffuser section to reduce the velocity of the combined stream to substantially the critical value, the pressure being increased at the same time; and (d) a divergent diffuser section to further decrease the velocity of the combined stream of gas. This equalizing nozzle is described and claimed in Specification 855,135, as applied to a steam turbine installation. To handle large quantities of gas, a plurality of equalizing nozzles may be connected in parallel and arranged adjacent to one another in the form of a ring. In this case, the individual nozzles would have a rectangular crosssection. Air compressed in a two-stage compressor K 1 , K 2 , Fig. 1, with intermediate cooling, is heated in a heat-exchanger WT by the turbine exhaust gases and then supplied to the combustion chamber Br which feeds the turbines T 1 , T 2 , through an equalizing nozzle D. A part of the exhaust gas from the turbine T 1  is increased in pressure and temperature in the nozzle D. The working medium may be reheated between the turbines T 1 , T 2 . In a modification, Fig. 3, for a propeller driving turbine, the high-pressure turbine T k  drives the compressor K and the low-pressure T turbine drives the propeller. The equalizing nozzle D supplies working fluid to the turbine T k  and is supplied with low-pressure medium bled from the low-pressure turbine T. In a modification, Fig. 4 (not shown), the nozzle D supplies highpressure working fluid to the turbines T K  and T which are arranged in parallel and the exhaust of the turbine T k  is supplied to the nozzle D as low-pressure medium. In a further modification, Fig. 5 (not shown), the nozzle D supplies high-pressure working fluid only to the highpressure compressor driving turbine T K  and the exhaust of this turbine is divided, part flowing to the nozzle D and part to the propeller driving turbine T. In two further modifications, Figs. 6 and 7 (not shown), the propeller driving turbine is omitted and the working fluid fed direct to a propulsion jet.