US2172993A - Turbine engine - Google Patents

Description

Sept. 12, 1939. G. D. STURTEVANT TURBINE ENGINE Filed Jul 14, 1933' s Sheets-Sheet 1 F g.1 v

' 1N VENTOR. 650%: D STuR'rEV/WT ATTORi EY.

P 12, 1939; I s, D. STURTEVANT I 2,172,993

TURBINE ENGINE Filed July 14; 1958 :5 Sheets- Sheet 2 i'NVENTOR. GEORGE D. STURTEVANT AT ORNEY.

P 1939- a. D. STURTEVANT 2,

' TURBINE ENGINE 7 Filed July '14, 1958 s sheets-sheet 3 INVENTOR. 650mg: D. J'TURTEV T a Y 'ATTORNEY.

Patented Sepia- 9 UNlTED [STATES PATENT OFFICE George D. Sturtevant, Cleveland, Ohio Application July 14 1938, Serial N0. 219,170

3 Claims.

This invention relates to an improvement in gas turbines of the type used for propelling heavy transitory bodies, as in the case of a locomotive, and especially to an improvement which permits the expansion of gas substantially at explosion temperatures, and it further relates to a novel method of expanding combustedgas for producing mechanical energy at an increased overall operating efliciency of the turbine.

Heretofore, gas turbines of this type have been operated by heavily jacketing the parts subjected to the high heats if the gas is expanded at the explosion temperatures, or, in some instances, water has been directly introduced into the gas at the nozzles for cooling the gas below the critical temperature of the metal in the blades, or a mixture of gas and steam has been formed before.

gas by use of water is that condensation of steam.

occursduring expansion of the gas, producing vacuums and consequently lowering pressures of the expanding gas, resulting in a further lowering of'the overall eflieiency of the turbine.

It is a principal object of this invention to provide an improvement in a gas turbine whereby gas may be admitted to the expanding nomies at the temperatures and pressures of the explosion of gas at constantpressure.

It is a further object of thisinventionto pro vide an apparatus for forming steam within the header so that the mixture can be expanded 0 v through a selected expanding nozzle, thereby decreasing materially the damage ordinarily occurring to the blades by the introduction of water directly'to a selected nozzle, as'heretofore described. 1

4,5 It is a further object of this invention to provide an apparatus within the header which superheats the steam formed from the water introduced into the header prior to its introduction into the nozzle.

It is a more specific object of this invention to provide a header construction and means in connection therewith for introducing gas into the nozzles'oi a high pressure stage of a .turbine, whereby gas at relatively high temperatures may 55 be introduced directly to an expanding nozzle or nozzles and the expanding blades of the apparatus are cooled by a mixture of gas and steam formed within the passage of the header before being introduced into a selected nozzle last receiving expanding gas from the passage within '5 the header.

Further; objects of this invention will become apparent from the specification and drawings, in

which:

Fig. 1 is a sectional view of an embodiment of 10 the invention;

Fig. 2 is an end view in elevation of the embodiment illustrated in Fig. 1; Fig. 3 is a diagrammatic illustration showing a system of various power producing elements for 15 supplying gas to the turbine; and

i Fig. 4 is a sectional view of the header taken along the line 4-4 of Fig. 1'.

In a power producing system which includes a gas turbine, an arrangement as illustrated in 20 Fig. 3 may be used. G enerally,.this system come prises a gas engine 20 to which is directly connected an air compressor 23 which is used for delivering air at substantially constant pressures to a carburetor 25. The carburetor 25 supplies 25 fuel to the gas producing .unit 24, and this unit in turn may be driven as by the gas engine 20' so that the combusted gases delivered from the unit are at higher temperatures and pressures. These gases are discharged from the unit and de- 30 livered to a drum 26 which stores the gas and also efiectively stabilizes the pressures and temperatures oi the gases entering therein which are passed into the turbine 21 for expansion.

The gas turbine used is of the ifnpulse type and- 35 comprises a housing i which is supported on a frame and base 3. A rotor shaft 2 extends through the housing and is supported by the bearings l and 5 which are supported by the frame 3. Onto the rotor 2 is mounted the blade 40 carrying members 6 which are so spaced along the length or the rotor as to define the expanding stages in th housing. Just ahead of each oi the blade carrying members 6;is a diaphragm I which ismounted into the housingfiand carries nozzles 8 therein which are spaced from the-axis of the rotor a sufilcient distance so as to cause the gases expanding therethrough to impinge the blades 9 mounted on the members 6. Ordinarily, as followed in present-day turbine. design and manufacture, the nozzles used in each diaphragm are three in number and are spaced substantially apart {or providing the proper balancing and sup port of the rotor.

The combusted gases enter through the inlet 5 nected thereto.

ating efilciency of the turbine.

l2 of a header H which is mounted onto the high pressure side of the housing I. The header II has a passage l3 therein which in turn has outlet openings H, a and Nb leading therefrom. These openings are spaced in the passage i3 so as to discharge the gases passing through the passage directly into the expanding nozzles located in the diaphragm of the high pressure stage. It is preferred that-the opening l2 of the header ll be located adjacent an opening M in the passage so that gas entering the opening l2 of the header can immediately pass through the opening and into a nozzle.

In order that all the gases entering the passage |3 may travel in one direction, there is provided a partition I! which closes ofl the travel of gases in the one direction and causes all gases entering the inlet H to pass into or by the opening [4 which is located adjacent the inlet opening and thence into an expanding nozzle con- This arrangement is advantageous in that it allows a portion of the undiluted gases passing through the inlet chamber to be immediately expanded through the turbine, thereby developing the maximum of energy by expansion of the hot gases. The portion of gases which passes by the opening it located adjacent the inlet opening [2 travels through the passage l3 to the next opening Ma, a part of which passes therethrough and the remainder of which passes to the last outlet opening Mb.

A second partition [8, completelyclosing off the passage i3, is located in the passage l3 beyond the opening Mb in the same general direction of travel of the gases and a predetermined distance therefrom so that water which may be admitted through a pipe 30 connected to the passage I3 is allowed to be transformed into steam before passing into the opening Mb. By reason of the velocity of the gases in the passage l3, the effect of the dead end passage formed by the partition I! in reducing the velocity of gas, as well as other factors, such as frictional resistance and steam formation, all aid in producing such a pressure condition around the vicinity of opening Mb which in turn causes the gas and steam mixture formed in the passage space between the opening Nb and the partition l8 to pass through the opening Nb and nozzle connected thereto and thence into the subsequent expanding stages of the turbine. It

is desired that a mixture of steamand gas be' admitted through only part of the nozzles since the effect of the mixture is to decrease the oper- As is the case generally in gas turbines, the greater portion of power developed by the gases is in the expansion through the first few stages of the turbine, and it is therefore advantageous and desirable for hot gases uncontaminated with steam to expand through these stages at substantially the temperatures and pressures of explosion at constant pressure or at which the gas passes into the header 7 Upon starting the turbine, the passage l3 may fill completely with hot gases before any substantial amount of gases passes through the openings in the passage l3 leading to the nozzles, but due to the general motion of the gases from the inlet duct I2 toward the turbine nozzles, which prevents a retrograde flow of the gases, the steam produced will remain in the passage space between the opening Nb and the partition l8, or at least be inhibited from passingin a reverse direction to the openings l4 and Ila.

' the blade surfaces.

' By admitting superheated steam into less than all of the nozzles,the effect is to cool the blades as they come into contact with the mixture, this being due, of course, to the lower temperature of the mixture as compared with the temperature of the hot gas. Furthermore, by passing the undiluted gas thronu gh some of theexpanding nozzles in the first or high pressure stage, greater kinetic energy is produced in these nozzles and consequently greater transfer of power to the blades. Cooling of the blades occurs as they come into contact with the steam and gas mixture being discharged from other nozzles in the same stage. By superheating'the steam' before admitting it into the expanding stages of the turbine, this eliminates or decreases materially the destruction caused to the blades by discharging a mixture of gas and partially vaporized water or saturated steam which may occur by admitting water directly in to the nozzle. By this invention, a mixture of gas and steam may be expanded through selected nozzles for the purpose of cooling, and relatively undiluted hot dry gas may be expanded through the remaining nozzles in the stage and the header is so arranged as to discharge hot dry gas into expanding nozzles with the least possible heat loss.

By this arrangement of directing the flow of gas through the passage II and into the expanding nozzles, and by the admission of water in a manner so that it is completely transformed into superheated steam, the efficiency of the turbine is materially increased and the rotor blades are maintained at a temperature below the critical point of the material of which such blades are made. A series of redirecting blades, as illustrated at 35, may be used and mounted directly onto the diaphragm l inthe first or high pressure stage in order to increase the production of power in this stage by taking advantage of the undiluted condition of hot gas. These stationary directing blades may be cooled by a water jacket within the housing, as illustrated at 36.

It is a matter of common knowledge that the fluid friction of superheated steam as it passes over the blade surfaces is materially less than thatof saturated steam and consequently it is advantageous that the steam existing in the gas in the expanding stages of the turbine be superheated. Likewise, if thesteam is heated only to a saturation point, the expansion of the gas and of the steam causes a condensation of the steam, resulting in the formation of vacuums within the stages and material decreases in gas pressure. Also, because of the high velocities of the mixtures, water vapor causes considerable damage to By the admission of gas directly from the drum 26, or as illustrated in Fig. 1, from the header II, to the several stages in the turbine, the steam is maintained substantially in a superheated condition. By so maintaining the steam in a conditon of superheat, an increased expansion occurs in the gases on passing through an expanding nozzle, correspondingly increasing the ppwer transfer. To accomplish this, a heavy pipe conductor 31 supported along a side of the turbine housing and base from which the smaller conductors'38 are connected thereto is illustrated as being connected to the header H. Each of the conductors 38 passes through the turbine housing I and is positioned in each of the stages just aheadof the diaphragm I in each stage so that the-gas passing from the succeeding stage comes into contact withthe gas being discharged from the conductor 38, causing a heating of the mixture and especially the steam component for producing greater expansion of the gases as they pass through the nozzles in the succeeding stages. As illustrated in Figs. 1 and 2, the conductor 38 has a valve 40 therein for controlling the supply of gases to its respective stage. This introduction of hot gas into'the expanding stages beyond the high pressure or initial stage equalizes the power production along the rotor so that increased power can be produced in these latter stages, whereupon more power is produced by the turbine and the power generation is distributed in a more equal fashion all along the rotor length.

Having thus described my' invention, I claim: 1. A gas turbine having a housing, a rotor supported by the housing, rotatable blades supported by said rotor, nozzle means mounted onto an end of said housing and in relation to the rotatable blades and comprising a circular header mounted onto the-nozzle end of said housing and having a central annular passage therethrough, said header having an inlet opening for connecting the passage-of the header to a source of-expansible-gas, a plurality of outlet openings in the pasasge and arranged for fluid connection with the nozzle means, a partition in the passage for causing all of the gas entering the headerto travel in one general direction of movement, a

water inlet means for introducing water into-the passage and positioned beyond the last outlet opening as defined by the one general direction of movement, and a second partition positioned be yond the water. inlet means as defined by the general direction of travel of the gas and positioned in a predetermined manner in-relatio'nto the last outlet opening, whereby substantially all of the gas and steam mixture formed by introducing water into the passage passes through the last outlet opening for effectively cooling the rotatable blades of the turbine.

2. A gas turbine header for a turbine engine having a housing, a rotor mounted within the I housing, a plurality of nozzles leading to an expanding stage of the turbine, blades mounted onto the rotor and positioned relative to said nozzles for receiving expansible heated fluid and comprising a header body having a central annular passageway with outlets connected to said nozzles, an inlet opening for receiving heated expansible fluid, a partition adjacent said inlet opening and in said passage for causing all fluid entering the passage to travel in one general direction .of movement, and means for introducing an evaporable cooling medium into the passage and positioned beyond the last outlet opening in the'passage defined by the one general direc- :tion of movement of the fluid, whereby the cooling medium, upon introduction into the passage, is evaporated and a substantial portion of the evaporated medium passes through said last outlet in the passage.

3. A gas turbine header for a turbine engine having. a housing, a rotor mounted within the housing, a-plurality of nozzles leading to an expanding stage of the turbine, blades mounted onto the rotor and positioned relative to said nozzies for receiving expansible heated fluid and comprising a header body having a central annular passageway with outlets connectedto said nozzles, an inlet opening for receiving heated expansible fluid, a partition adjacent said inlet opening and in said passage iar causing all fluid enteringthe passage to travel in one general direction of movement, a second partition in said passage for interrupting the flow of fluid in the one general direction of movement insaid passage and positioned in close proximity to the last outlet opening in the passage defined by the one general direction of movement of the fluid, and means for introducing an evaporable cooling medium into the passage and positioned between the second partition and said last outlet opening, whereby the cooling medium is evaporated upon introduction into the passage and a substantial portion of the evaporated medium passes through said last outlet opening in the passage to the expanding-stage of the turbine.

GEORGE D. STURTEVANT.

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