US2141401A

US2141401A - Gas turbine

Info

Publication number: US2141401A
Application number: US124407A
Authority: US
Inventors: Martinka Michael
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-07-01
Filing date: 1937-02-06
Publication date: 1938-12-27
Anticipated expiration: 1955-12-27
Also published as: BE431387A

Description

M. MARTINKA Dec. 27,, 1938.

GAS TURBINE 3 Sheets-Sheet 1 Filed Feb. 6, 1937 OOOGOOOOOOOOGQOOO Jnaen/ar: W

5 M A far/75y Dec. 27, 1938. M. NIIARTINKA 1,

GAS' TURBINE Filed Feb. 6, 19s"! a Sheets-Sheet 2 Dec. 27, 1938'. M. MARTINKA 2,141,401

r GAS TURBINE -Filed Feb. 6, 1937 's Sheets-Sheet 3 Fig. 12

7/71/5072 (m/kw Afiarney was Dec..27, 193s PATENT OFFICE Glam mohaelnlutinkanuisbnmcennany Application February 8,

In Germany 120kbps.

, My invention relates to improvements in that class of rotary power producing machines, known as gas-combustionor explosive-turbines, in which an elastic working fluid-generally the gaseous combustion products of a mixture of fuel and air-violently flow at high velocity and temperature across the crown of blades of the rotary turbine wheel.

Turbines of that class, collectively hereinafter called gas-turbines, are distinguished from the more widely known class, of steam turbines by the unusually high range of temperatures, -ranglng considerably above 500 centigrade,at which the gaseous working medium reacts upon the blades of the rotary turbine wheel, briefly hereinafter called rotor", and by the greater working dimculties, generally accompanying, high temperatures, and calling for extraordinary precautionsviz. the provision of highly eflicier t cooling expedlents-in order to prevent destructive overstraining of the material, of which the rotor, its web and its blades are made.

vAs a matter of fact, the rotary speed, at which gas-turbines can be safely worked, and on which their efliciency largely depends, is limited 1. Because of the heat radially flowing from the highly heated blades into the rim oi the rotor, wherein the blades are flxed,namely by what may be conveniently called the heat stresses 0 induced in said rim by the great drop of temperatures, from t to t2, which are diagrammatically indicated in Fig, 12, and

2. Because of the mechanicalstresses, which are imparted in addition to the heat stresses to 5 the rotor rim, by the violent. centrifugal forces produced, while the turbine is in operation.

Practical experiments made with'gas-turbines in state of development have shown, that the rotor rim is one of their most critical and perilous 0 parts, and that the maximum rotary speed, at which the rotor can be safely revolved under the existing conditions, and with the cooling expedients known is about 230 meters per second measured at the blades:

Briefly stated the invention aims at providing a structurallyimproved gas-turbine, which can be safely worked at a higher speed, and which will show a higher efliciency, and a greater output in horsepower units per unit of weight of the turbine,-the ultimate object being tomake the improved gas-turbine lit for being used even on aeroplanesfzeppelin-air-ships. and kindred air craft, where the light weight of the motors and safety of their operation are. the predominant' considerations.

1m, serial No. July 1, 1m

ing them with structurally simple, reliable cooling expedlents, gentlyacting by means of gases, that the temperatures throughout the web are practically equal and uniform. v

The invention employs gaseous currents for cooling the roots of the blades hereinafter called "shanks"; the latter are preferably elongated in radial direction, and are provided with recesses enclosing cooling chambers, and with anchors for fixing those blade structures in the rim of the turbine wheel.

Another salient feature or the invention is the provision of means for cooling the web of the turbine wheel by means of currents of a gaseous agent, recirculated in closed cycles of movement therearound, and of means for re-cooling the said gaseous currents in a specific graduated manner, namely in proportion to the respective amounts of heat to be dissipated at the said shanks of the blades and at the various zones of the web of the turbine wheel,and with the object of keeping the temperatures relatively low and practically constantand uniform throughout the whole'web.

The nature and scope of the invention are briefly outlined in the appended claims, and will be more fully understood from the following speciflcation taken together with the accompanying drawings, in which a gas-turbine redesigned according to this invention is shown by way of an example:

Fig. 1 is a fragmentary section taken vertically through the turbine on line I-I in Fig. 2; I

Fig. 2 is aside elevation of the turbine, drawn on a smaller scale; a

Figs. 3 and 4 show in enlarged scale the annular cooling ribs, enclosing the web of the turbine wheel, in cross section and in side elevation;

Figs. 5 and 6 show perspectively the blades redesigned according to this invention;

Figs. '1 and 8 are side elevations showing one of the blades with their shank as seen from either Fig. 12, which is a diagram, shows the development of temperatures within the blades, their shanks, the rim, web and nave of the turbine wheel.

With the objects in view outlined above the gas-turbine re-designed according to this invention essentially consists of:

1. A housing or stator 20, 2|, formed with a combustion chamber 22 of substantially circular cross sectional shape having a cooling jacket 22 and being connected with pipes, not shown, through which fuel and air are supplied thereinto; the gaseous products of combustion pass through an intake nozzle 28 on their way to the blades of the turbinewheel described hereinafter. and finally escape through the discharge nozzle 25,

2. Ribbed radiators presenting annular recesses, in which a gaseous cooling medium circulates, the latter being re-cooled by 3. Cooling Jackets, through which cooling liquids, preferably water, circulate:

The said radiators comprise two pairs of cooling ribs 35, 30', 32, 32', enclosing annular re- .cesses r, r (Fig. 3) of approximately circular cross sectional shape, and another pair of cooling ribs 34, 34', which jointly enclose an annular recess of substantially oval cross sectional shape 1'" and closely surround at both sides the respective cooling elements attached to and interal with the

blades

3a, 3b of the turbine wheel referred to in detail hereinafter.

The radiator ribs 32, 32' and 3d, 3d are in direct contact with the cooling medium passing through the cooling jackets 42. 42' and M, 44, while the ribs 30, 30' and Jackets 40, 40' are spaced from each other, so as to indirectly act upon each other through radiation.

The stator 20, 2| of the gas-turbine encloses the bladed turbine wheel or rotor, journalled therein at 25, 26 and comprising 4. A web 50, which is preferably integral with the nave 52 of the rotor;

5. Toothed prongs 55, radially projecting from said web 40, the lateral faces or flanks of said prongs extending parallel to the axis of the turbine wheel;

6. A crown of blades attached to the rim of the'rotor, and consisting of pairs of differently shaped blade structures, the blades proper of which 3a, 3b are attached to shanks 4a, 4b, and are secured to the rotor rim by means of toothed roots or anchors 5a, 5b, projecting from said shanks; the flanks of said anchors are axially directed, so as to engage the corresponding faces of said prongs 55 of the turbine wheel.

The said shanks 4a., 4b, provided and arranged according to this invention and in contradistinction to prior art gas-turbines intermediate the blades and their roots, are so designed as to act at the same time as blade carriers. and blade cooling and spacing members, namely to keep the

blades

3a, 3b-being the hottest portion of those blade structuresa considerable distance apart from the rotor rim, its prongs 55, and the rotor web,thus providing a zone of ample width, which is not integral with the rotor rim,

but onlyin contact therewith, and wherein the drastic drop of temperatures from t to t2 referred to above and shown in Fig. 12 takes place.

A salient feature of said blade structures, not visible in the drawings, consists therein, that they are fitted together and into their places at the rotor rim with such allowances as to their width, that they are capable of individually expanding to a predetermined extent. Chos n as to prevent excessive "heat stresses of the character described in the preamble, which would occur, if the blade structures were fitted rather tightly and under considerable initial pressure against each other, and into their places between the prongs 55 of the turbine wheel.

For cooling purposes the'said shanks 4a, 4b are preferably of double T or I cross sectional shape, best seen in Fig. 10 at the right, namely they are formed with lateral

walls having holes

40, 4c, 4d, 4d, and recesses 4e, 4e, so designed, that every two blade structures adjacently disposed to each other present a cooling chamber having an intake port at 4e, 4e, and two

discharge holes

40, 4c.

The anchors a, 5b of the blade shanks termi-- nate shortof the root portions of the prongs 55, so as to enclose intake ports 55', and are formed with a plurality of grooves opposed to each other, presenting channels 51', through which the cooling air, drawn in through intake ports 55, passes into the respective cooling chambers; the courses upper faces, so as to present at their outer ends a practically non-interrupted cylindrical surface except for the said holes; the same is true with regard to the lower and inner ends of the

blades

3a, 3b, where corresponding fianges 3f are provided, fitting together so as to present a con-,

tinuous line of border elements; as seen on Figs. 5, 6, said lower flanges are formed at their bottom with curved faces 30 for deflecting the cooling air, discharged through the

holes

4c, 40, 4d, 4d.

The operation of the cooling expedients provided at the gas-turbine described above-is as follows:

The bulk of the heat passing by conduction from the highly heated crown of blades into their shanks 4a, 4b is transferred therefrom to the currents of cooling gas, which are positively circulated through the respective cooling chambers, shown and described with reference to arrows a: and 3/ by centrifugal forces, produced and comparable to those active in a bladed centrifugal fan or pump. The drop of temperatures, provoked within the shanks 4a, 4b of the blade structures, is indicated by diagram line t--t2 in Fig. 12.

The heated gas discharged through the

holes

40, 4c, 4d, 4d is intensely re-cooled on travelling take ports 55' and through the channels 52'; the

change of temperatures being indicated in Fig. 12

by diagram line ti -t3.

The rest of the heat reaching on its travel in radial direction the ,web proper of the turbine wheel is transferred therefrom by all those annular currents of cooling gas, which are enclosed having anchors for 32, 32', and are iorced to I circumferential direction by the ribs 30, 30', travel therebetween in indicated by arrow s (Fig. 4) by reason oi. their frictional contact with the surfaces of the web The said

cooling ribs

30, 30", 32, 32', and in turn the currents of gas circulating therebetween are recooled, substantially in proportion to the decreasing amounts of heat to be dissipated by the cooling jackets 42, M, which are in direct contact with the ribs 32, 32',-and by the cooling Jackets 40, Mi arranged at a distance from the ribs 30, 30', so as to indirectly act upon each other through radiation.

Various changes and modifications may be conveniently made in the structural details of gasturbines of the improved design described and in the shape, assemblage and cooperation of their cooling expedients, without departing from the spirit and the salient ideas of this invention:

For instance guide elements in the form of twisted strips of sheet steel, of which a short piece is shown at 60 in Fig. 4. may be provided within the recesses enclosed by the ribs 86, 8b, 32, 32', in order to cause the annular currents of cooling gas, travelling in circumferential direction, to attain at the same time a twisting motion, and to thereby enhance the emciency of both the primary and secondary cooling medium.

The secondary cooling medium-preferabiy water-should be positively circulated by a pump P (Fig. 2) through the cooling jackets in the direction of the arrows i-o and i'--o', and be recooled by a radiator R or other appropriate means known per se and shown in Fig. 2: 3

In other words the coolest water should enter the jackets M, M opposed to the shanks do, db of the turbine blades, in order to most eilectively cool the hottest part of the rotor; and should thence pass through the jackets t2-4it, and iT-til', in such manner, that the cooling effect is graduated according to local heat conditions at the rotor rim and web.

What I claim is:

- 1. In a gas-turbine, having a bladed rotor and a housing, enclosing and supporting said rotor. the combination with a crown of blade structures. having anchors for fixing the blades at the rotor rim and relatively wide, hollow shanks arranged intermediate the said anchors and the blades proper,--of primary cooling means, employing a plurality of gaseous currents re-circulated in closed cycles of movement through said hollow shanks and around the rim and web of the rotor,and secondary cooling means for re-cooling the respective gaseous currents in proportion to the amount of heat to be locally dissipated.

2. In a gas-turbine, having a bladed rotor and a housing, enclosing and supporting. said rotor, the combination with a crown of blade structures, fixing the blades at the rotor rim and relatively wide, hollow shanks arranged intermediate the said anchors and the blades proper,-of primary cooling means, employing a plurality of gaseous currents re-circulated in closed cycles of movement through said hollow shanks and around the rim and web of the rotor,-and secondary cooling means for re-cooling the respective gaseous currents in proportion to the amount of heat to be locally dissipated,- said shanks being of I cross sectional shape so as to present recesses at opposed sides so interengaging each other, that every two adjacently disposed blade structures enclose a cooling chamber.

8. In a gas-turbine, having a bladed rotor and a housing, enclosing and assault. we rotor. the combination with a crown of blade structure having anchors for fixing the blades at the rotor rim and relatively wide, hollow shanks arranged intermediate the said anchors and the blades prope'n-oi primary coolingmeans, employing a pinralityof gaseous-currents re-circulated in closed cycles oi movement through said hollow s and around the rim and web of the rotor,-and secondary cooling means for re-cooling the respective gaseous currents in proportion to the amount of heat to be locally dissipated, said shanks being of I cross sectional shape so as to present recesses at opposed sides so lnterensa ng each other, that every two adiacently disposed blade structures enclose a cooling chamber,-tbe latter being provided with intake ports and discharge holes at their lower and upper ends.

4. In a gas-turbine, having a bladed rotor and a housing, enclosing and supporting said rotor, the combination with a crown of blade structures, having anchors for fixing the blades at the rotor rim and relatively wide, hollow sha arranged intermediate the said anchors and the blades proper,-o primary cooling means, elmploying a plurality of gaseous currents re-circulated in closed cycles of movement through said hollow shanks and around the rim and web of the rotor,-andsecondary cooling means for recooling the respective gaseous currents in pro- W portion to the amount of heat to be locally dissipated,-the rotor rim presenting toothed prongs, spaced from each other for engagement with pairs of said anchors of the blades.

5. In a gas-turbine, having a bladed rotor and a housing, enclosing and supporting said rotor, the combination with a crown of blade structures, having'anchors for fixing the blades at the rotor rim and relatively wide, hollow shanks arranged intermediate the said anchors and the blades proper,--of primary cooling means, employing a plurality of gaseous currents re circulated in closed cycles of movement through said hollow shanks and around the rim and web of the rotor,-and secondary cooling means for re-cooling the respective gaseous currents in proportion to the amount of heat to be locally dissipated,--the said anchors of the blades being the combination with a crown of blade structures, having anchors for fixing the blades at the rotor rim and relatively wide, hollow shanks arranged intermediate the said anchors and the blades proper,-of primary cooling means, em-

ploying a plurality of gaseous currents re-circulated in closed cycles of movement through said hollow shanks and around the rim and web of .the rotor,-a.nd secondary cooling means for re-cooling the respective gaseous currents in proportion to the amount of heat to be locally dissipated,--the rotor being formed with spaced prongs for engagement with the anchors. oi' the turbine blades, the latter being proportioned and mounted in their places with such allowances in cold condition, that they are capable of individually expanding in heated condition.

7. In a gas-turbine, having a bladed rotor and a housing, enclosing and supporting said rotor, the combination with a crown of blade structures, having anchors for fixing the blades at the rotor rim and relatively wide, hollow shanks arranged intermediate the said anchors and the blades, proper,--of primary cooling means, employing a plurality of gaseous currents re-circulated in closed cycles of movement through said hollow shanks and around the rim and web of the rotor,and secondary cooling means for re-cooling the respective gaseous currents in proportion to the amount of heat to be locally dissipated,--the said primary cooling means comprising a plurality of cooling ribs, the front faces of which being opposed to said shanks and anchors of the blade structures, and to the rim and web of the rotor respectively, while their rear faces are opposed to the said secondary cooling means.

8. In a gas-turbine, having a bladed rotor and a housing, enclosing and supporting said rotor, the combination with a crown of blade structures, having anchors for fixing the blades at the rotor rim and relatively wide, hollow shanks arranged intermediate the said anchors and the blades proper,of primary cooling means, employing a plurality of gaseous currents re-circulated in closed cycles of movement through said hollow shanks and around'the rim and web of the rotor,and secondary cooling means for recooling the respective gaseous currents in proportion to the amount of heat'to be locally dissipated, the saidprimary cooling means comprising a plurality of cooling ribs, the front faces of which being opposed to said shanks and anchors of the blade structures, and to the rim and web of the rotor respectively, while their rear faces are opposed to the said secondary cooling means,--the latter employing a liquid cooling agent.

9. In a gas-turbine, having a bladed rotor and a housing, enclosing and supporting said rotor, the combination with a crown of blade structures, having anchors for fixing the blades at the rotor rim and relatively wide, hollow shanks arranged intermediate the said anchors and the blades proper,-if primary cooling means, employing a plurality of gaseous currents re-circulated in closed cycles of movement through said hollow shanks and around the rim and web of the rotor,- and secondary cooling means for re-cooling the respective gaseous currents in proportion to the amount of heat to be locally dissipated, the said primary cooling means comprising a plurality of cooling ribs, the front faces of which being opposed to said shanks and anchors of the blade structures, and to the rim and web of the rotor respectively, while their rear faces are opposed to the said secondary cooling means, the latter employing a liquid cooling agent,and comprising a plurality of ring shaped jackets, through which said liquid cooling agent circulates.

10. In a gas-turbine, having a bladed rotor and a housing, enclosing and supporting said rotor, the combination with a crown of blade structures, having anchors for fixing the blades at the rotor rim and relatively wide, hollow shanks arranged intermediate the said anchors and the blades proper,of primary cooling means, employing a plurality of gaseous currents re-circulated in closed cycles of movement through said hollow -shanks and around the rim and web of the opposed tosaid shanks and anchors of the blade structures, and to the rim and web of the rotor respectively, while their rear faces are opposed to the said secondary cooling means, the latter employing a liquid cooling agent, and comprising a plurality of 'ring shaped jackets, through which said liquid cooling agent circulates-the outermost set of cooling ribs, opposed to the peripheral zone of the turbine rotor being integral with their respective cooling jackets, while the innermost cooling ribs, opposed to the web of the rotor, are spaced from the cooling jackets oi the innermost set.

11. In a gas-turbine, having a bladed rotor and a housing, enclosing and supportingsaid rotor, the combination with a crown of blade structures, having anchors for fixing the blades at the rotor rim and relatively wide, hollow shanks arranged intermediate the said anchors and the blades proper,of primary cooling means, employing a plurality of gaseous currents re-circulatedi in -closed cycles of movement through said hollow shanks and around the rim and web of the rotor,- and secondary cooling means for re-cooling the respective gaseous currents in proportion to the amount of heat to be locally dissipated, the said primary cooling means comprising a plurality of cooling ribs, the front faces of which being opposed to said shanks and anchors of the blade structures, and to the rim and web of the rotor respectively, while their rear faces are opposed to the said secondary cooling means,--the cooling ribs, opposed to the rotor rim and web enclosing annular spaces, wherein twisted strips are provided adapted to act as guide elements and causing the gaseous currents circulating therebetween to perform at the same time a trundling motion,

12. In a gas-turbine, having a bladed rotor and a housing, enclosing and supporting said rotor, the combination with a crown of blade structures, having anchors for fixing the blades at the rotor rim and relatively wide, hollow shanks arranged intermediate the said anchors and the bladesv proper,of primary cooling means, employing a plurality of gaseous currents re-circulated in closed cycles of movement through said hollow shanks and around the rim and web of the rotor,and secondary cooling means for re-cooling the respective gaseous currents in proportion to the amount of heat to be locally dissipated, the said primary cooling means comprising a plurality of cooling ribs, the front faces of which being opposed to said shanks and anchors of the blade structures, and to the rim and webof the rotor respectively, while their rear faces are opposed to the said secondary cooling means, the latter employing a liquid cooling agent, and comprising a plurality of ring shaped jackets, through which said liquid cooling agent circu1ates,-and which are interconnected in series so that the coolest liquid enters the outermost cooling jackets.

' MICHAEL MARTINKA.