US1961615A - Elastic fluid turbine of the radialaxial flow type - Google Patents

Description

Juhe 5, 1934. A, LYSHOLM 1,961,615.

' ELASTIC, FLUID TURBINE oF THE RADIAL AXIAL FLOW TYPE original Filed April 19, 1929 s Sheets-sheet 1 June 5, 1934. A. LYsHoLM l 1,961,615v I ELSTIC FLUID TURBINE OF THE RADIAL AXIAL FLOW TYPE Original Filed April 19, 1929 3 Sheets-Sheet 2 June 5, 1934.

A.- LYsHoLM ELASTIC FLUID TURBINE OF THE RADIiAL AXIAL FLOW TYPE Original Filed April 19, 1929 3 Sheets-Sheet 3 UNITED STATES PATENT OFFICE ELASTIC FLUID TURBINE F THE RADIAL- AXIAL FLOW TYPE Alf Lysholm, Stockholm, Sweden, assigner to Aktiebolaget Ljungstroms Angturbin, Stockholm, Sweden, a joint-stock company. of Sweden Application April 19, 1929, Serial No. 356,488. Renewed April 20, 1932. In Sweden April 23, 1928 14 Claims. (Cl. 253--16.5)

The present invention relates to elastic uid to most effectively separate the moisture from the turbines and has particular reference to turbines steam discharged from the radial flow blade sysof the so-called Ljungstrom type in which the tem before it is delivered to the axial iiow bladmotive fluid passes first through a radial now ing. It is.a further object of the invention to blade system from which it is discharged to bladprovide an improved turbine construction wherein ing of the axial flow type. Still more particuthe heat of the moisture separated from the steam larly, the invention relates to steam turbines of between the radial ow and axial ow blade sysrelatively large size and of the double rotation tems may be most eifectively utilized. type in which motive fluid discharged from the The nature of the invention and the manner radial flow blade system is divided into two in which the above and other and more detailed streams each of which passes through a separate objects of the invention are attained may best axial flow blade system. be understood by reference to the following de- In turbines of this kind the steam discharged scription of suitable forms of apparatus for carfrom the outermost ring of blades in the radial rying the invention into effect. flow blade system passes to a space radially out- In the drawings accompanying this specicaside of the radial ow blade system from which tion: space it flowsr axially to the axial ow blading of Fig. 1 is an axial central section of a part of a the turbine. In its passage through the radial turbine of the double rotation type embodying the flow blade system the pressure and temperature invention; b of the steam both drop and as a result the steam Fig. 2 is a section similar to Fig. 1 showing a 70 entering the space between the blade systems different construction of part of a turbine of the ordinarily contains a relatively large percentage kind shown in Fig. 1; of moisture. Also, the steam leaving the radial Fig. 3 is a section similar to Fig. 2 showing still flow blade system ordinarily is discharged thereanother form of construction; from in generally radial direction and in order to Fig. 4 is a section similar to Figs. 2 and 3 show- 75 provide for efficient admission of steam to the ing still another form of construction; first row of moving blades ofthe axial flow blade Fig. 5 is a section, on reduced scale, taken on system, it is desirable to` impart to the steam a line B-B of Fig. 4; certain amount of peripheral motion. It has Fig. 6 is a section taken on the line C-C of Fig. heretofore been suggested to provide guide blade 4; and, structure between radial flow and axial ow blade Fig'. 7 illustrates diagrammatically another systems for the purpose of imparting some peform of guide blade arrangement in a turbine of ripheral motion to the steam entering the axial the general type shown in Fig. 1. ow blade systems but in the forms of construc- Turning now to Fig. 1 of the drawings, the tion heretofore proposed, substantial loss in efline A-A designates a plane normal to the axis ciencyis incurred because of the expansion and of rotation of the turbine with respect to which loss of velocity in the steam entering the space plane the turbine is-substantially symmetrical. between the blade systems and its reacceleration The turbineillustrated comprises two oppositely by guide blade structure situated adjacent to the rotating turbine shafts each carrying a rotor and first moving ring orrings of axial now blading. the rotors in turn carrying the blade rings com- It is one of the principal objects of the invention prising the moving blades of the turbine. Since to provide improved guide blade means between these shafts and rotors are alike in construction radial ow and axial flow blade systems, so arit will be necessary to describe only the construcr ranged as to minimize or eliminate the losses tion of one. Reference numeral 2 designates one 4" heretofore encountered in that portion of the of the turbine shafts which carries a rotor com- 95 path of flow of the steam between the radial flow prising an inner part 3, an intermediate part 4 and axial flow blade systems. Another of the and an outer part 5. Parts 3, 4 and 5 are conprincipal objects of the invention is to provide nected by means of a plurality of radially extendguide blade means for guiding the steam dising bolts 33, one of which is shown in the figure, charged from the radial flow blade system so as the outer ends 0f which pass through suitable 100 apertures in rings 31 and 32 shrunk onto and forming a part of the outer rotor part 5.

'I'he inner parts 3 of the two rotors carry the rings of radial flow blades comprising the inner or high pressure section of the radial ow blade system by means of articulated connections 6 which are advantageously in the form of expansion rings. Similarly, the intermediate rotor parts 4 carry the blade rings of the intermediate pressure section of the radial flow blade system by means of expansion rings 7. The outer rotor parts 5 carry the rings of radial flow blades comprising the last and lowest pressure section of the radial flow blade system by means of expansion rings 14.

The outer rotor parts 5 also carry the rings of moving blades 10 and 11 of the axial flow blade system which, in the present instance, is divided into two sections at axially opposite sides of the central plane A-A of the turbine.

Between the last radial flow blades 36 and the first rings of axial flow blades 10 is a space indicated generally at 27, which is divided by a central radially extending partition 35 into two channels 29 and 29a. Between partition 35 and annular radially extending side walls 40 there are two rings of stationary guide blades 28, the inlet edges of which extend substantially parallel to and in relatively close proximity to the outlet edges of the radial flow blades 36.

Blades 28 extend substantially axially of the turbine and in the embodiment illustrated, the blades extend from closely adjacent the radial flow blades 36 to a point closely adjacent to the rst rings of moving blades 10 of the axial flow blade system. Consequently, in this embodiment, the length of the guide blades in the general direction of flow of the steam is greater than the width of the blades.

Steam leaving the last ring of radial flow blades 36 passes to the axial flow blade system in the general direction indicated by the dot-and-dash line 37 and from an inspection of the figure it will be evident that the steam immediately upon leaving the radial flow blade system passes into a plurality of separate passages subdividing the channels 29 and 29a which are formed by the partition 35, the walls 40 and blades 28. Due to the fact that the cross-sectional area of these passages is much smaller than the cross-sectional area of the open space 27 between the rotor parts 5, the steam in passing from the radial now blade system to the axial flow blade system will not expand and lose velocity as would be the case if the passages formed by the guide blade system were not provided. Furthermore, due to the curvature in peripheral direction of the guide blades 28, the steam entering the passages between these guide blades at high velocity is given a peripheral whirling motion which eiectively separates the moisture or condensate in the steam. This moisture flows along the walls of the channels formed by the partition 35 and passes radially outwardly of the axial flow blades 10 and 1l and between the stationary guide blades l2 along the inner surfaces of the rings 13. Condensate thrown from the surfaces of the rings 13 passes into the outlet space of the turbine surrounding the blade systems and indicated generally at 30.

Preferably, the guide blades 28 are arranged so that the steam leaves these blades with the same peripheral velocity as that at which the moving blades of the axial blade system rotate. Thus, if it is assumed that the right hand turbine part 5 in Fig. 1 rotates so that the blades l0 and 11, shown in the figure, rotate inwardly toward the paper, the convex surfaces of the right hand guide blades 28 will appear in the ligure, whereas, the concave surfaces of the left hand blades 28 will appear in the gure since the left hand rotor part 5 rotates in a direction opposite the direction of rotation of the right hand rotor part.

Referring now to Fig. 2, parts similar to those in Fig. l have been designated by corresponding numerals. In this form of construction, the partition 35, as in Fig. 1, divides the space between the last ring of radial flow blades 36 and the first ring of axial flow blades 10 into two channels, only one of which is shown at 29. The partition carries rings of guide blades 28, the axial outer edges of which are joined by the radial Wall 40. Guide blades 28, however, do not extend all of the way through the channel 29 but the outlet edges, as indicated in the gure, are spaced a substantial distance from the first ring of moving axial flow blades 10. In this form of construction the blades 28 do not need to be of special shape in order to properly conduct the steam from the radial flow blade system to the axial now blade system but may be of usual form for turbine blading. The steam is discharged rotationally into the annular space formed by the radially outer part of channel 29 and from this space is deflected in generally axial direction into the axial flow blade system by the outer wall portion of the partition 35.

Due to the rapid rotational movement of steam discharged to the outer portion of the channel 29, moisture is separated from the steam due to centrifugal force and a number of ports or openings 41 are provided in the annular ring 13 through which the separated moisture is discharged to the outlet space of the turbine. As

will be seen from the figure, ports 41 are situated ahead of the first ring of axial flow blades in the direction of flow of steam so that the moisture is removedbefore the steam reaches these blades.

The structure shown in Fig. 3 is generally similar to that shown in Fig. 2 but in the present arrangement, the annular ring-like part 13, from which the partition 35 extends radially inwardly, has formed thereon an angularly disposed flange 43 for guiding steam from channel 29 to the axial flow blade system and for separating this -channel from an annular chamber 42 which is radially outside of and in communication with channel 29 at a point adjacent to the rst ring of axial ow blades 10. The radially outer wall of chamber 42 is provided with a plurality of ports 4l which ports it will be noted are of somewhat larger area than the ports 41 shown in Fig. 2.

The action of the guide blades 28 in this arrangement is similar to that in the arrangement shown in Fig. 2 and moisture separated from the steam flows through the chamber 42 and the ports 41. In addition to the moisture passing to the chamber 42, a certain amount of steam may also ow to this chamber and the fluid in this chamber, due to the rotational movement of the fluid in channel 29, will also have a whirling or rotational movement.

As shown in Fig. 4, the chamber 42 may advantageously be utilized as a heating chamber for extracting heat from the steam and moisture passing through this chamber. In the arrangement shown in Figs. 4 and 5, chamber 42 is utilized for the reception of a feed water heater comprising a number of pipe coils 44 xed in suitable headers `to which water is supplied through the inlet conduit 46 and from which it is discharged through the outlet conduit 47. Advantageously, the coils and headers are arranged in the manner shown in Fig. '5 to provide series flow of Water through the coils and also to permit separation of the parts along a central longitudinal plane. For the sake of clarity the coils 44 in Figs. 4 and 5 have been shown out of proportion, it being preferable to employ a much larger number of coils having relatively smaller cross-sectional diameter.

In order toassist in the axial flow of steam across the coils 44, additional ports 45 are provided which may advantageously be connected to an ejector or equivalent suction producing device.

The chamber 42 provides a particularly efflcientheating chamber for feed water coils or the like since, due `to the rapid rotational movement of the steam in this chamber, resulting from l the action of the guide blades 28, the rate of heat transmission from the steam to the coils is greater than would be the case if the steam did not have this rotational movement.

Fig. 6 indicates diagrammatically the guide blade arrangement andthe character of the ilow of steam leaving the last blade ring 36 of the radial flow system. In the velocity triangle shown inthe ligure, 50 represents the direction and velocity of discharge of the steam relative to the blades 36, 49 represents the peripheral velocity of the blade ring 36 and 48 represents the absolute direction and velocity of the steam discharged from the blade ring. The magnitude and direction of the relative velocity 50 should be selected with respect to the peripheral velocity 49 so that the absolute direction of ilow of the steam to the guide blades 28 is approximately radial,` `as indicated by the vector 48.

In the ligure, the blades 28 at one side of the partition 35 are shown in full lines and the blades at the opposite side of the partition are shown in dotted lines at 51. As previously explained in connection with Fig. 1, the guide blades 28 on opposite sides ofthe partition are oppositely curved as indicated in Fig. 6 and it will b e evident `from this figure that radial discharge of steam from the ring of blades 36 will operate to admit steam in like manner to each of the sets of guide blades 28 and 51.

In the arrangement shown more or less diaygrammatically in Fig. '1, the central partition 35` is divided so as to provide guide surfaces diverging symmetrically in axial direction with respect to the central transverse plane of the turbine. Furthermore, in this embodiment the two rings of guide blades between the last ring of radial flow blades 36 and the rst ring of Y axial ow blades 10, indicated in this `view at 28 and 51, are shorter radially than in theforms of apparatus previously described. In this form of apparatus, however, the guide blades function in the same manner as the corresponding `blades previously described to impart a peripheral or whirling motion to the steam immediately upon vits discharge from the last ring of radial flow blade-s. This action, regardless of the specific proportion of the guide blades with respect to comparative length and width, operates to irnprove the turbine eiiiciency, as has been previously pointed out, and also operates to effect improved separation of moisture from the steam because of the augmented centrifugal force acting on the moisture particles in the space between 28, this `will depend'to the radial flow blade system and the axial ow blade system.

From the preceding description it will be obvilous that the number of partitions employed to divide the steam may be varied. In all of the structural examples hereinbefore described, the axial flow blade system has been shown as comprising two sections. It will be evident, however, that the axial flow blade system may be divided into different numbers of sections in which case the partitioning should be arranged so that each of the sections receives substantially the same proportion of the steam admitted to the radial izlow blade system as do the other axial flow secions.

As is shown in Fig. 7, if the axial flow blade section or sections comprise only a single ring of moving blades, the only guide blade apparatus required is the ring of guide blades disposed between the last ring of radial flow blades and the single ring of axial iloW blades.

With respect to the relation of the axial and radial proportions of the rings and guide blades a great extent upon the size of the turbine. In the smaller sizes of turbines the axial dimension of the passages for conducting steam from the radial flow system to the axial flow system may be comparatively small and the axial flow blading may be disposedlal substantial distance radially outwardly from the outermost ring of radial ilow blades, as in Fig. 1. In a turbine of this character comparatively narrow and long guide blades can be employed. y `In large turbines the axialdimension of the-steam passage at the outlet of the radial ilow blade system must be comparatively large and `due to centrifugal forces acting on the rotor parts, the diameter of the axial flow blade rings cannot be made much greater than the diameter of the outermost ring of radial ow blades. This gives a relationship of the dimensions of the parts such as is indicated in Fig. 7 and consequently, the guide blades in a turbine of this character must be relatively wide and short. l

Many changes and variations in the construction hereinbefore described may be made without departing from the invention the scope of which is defined in the appended claims.`

What I claim as new and desire to secure by Letters Patent of theUnited States of America ls.

1. In an elastic fluid turbine, the combination with one or more radial flow blade systems and one or more axial flow blade systems spaced therefrom, of guide means located in the space between the radial ow and axial iiow blade systems and directly gu'ding the elastic fluid exhausted from the last moving ring of blades of said radial flow blade system to the first or single moving ring of blades of said axial ow blade system, said guide means comprising guide blades the inlet edges of which extend substantially parallel to and in close proximity to the outlet edges of the blades of the last moving blade ring of the radial flow system.

2. In an elastic iiud turbine, the combination with one or more radial flow blade systems and one or more axial ow blade systems, of guide blade apparatus including one or more rings of guide blades for each of said axial flow blade systems, the single or rst of said rings being system and having blades extending substantially axially of the turbine.

3. In an elastic fluid turbine, in combination, one or more radial flow blade systems and one or more axial flow blade systems, guide blade apparatus including one ork more rings of guide blades for each of said axial flow blade systems, the single or rst of said rings being disposed in close proximity tothe 'outlet edges of and in radial continuation of the blades of the last moving blade ring of the radial flow blade system and comprising blades having a greater extent in the main direction of flow of the elastic fluid through said rings than at right angles to said direction.

4. In an elastic fluid turbine, in combination, one or more radial flow blade systems and one or more axial flow blade systems, guide blade apparatus including one or more rings of guide blades for each of said axial flow blade systems, the single or first of said rings being disposed in radial continuation of the blades of the last moving blade ring of the radial flow blade system and inlet passages for said single or rst ring of guide blades situated in close proximity to the outlet edges of the blades of said last moving blade ring.

5. In an elastic fluid turbine, in combination, one or more radial flow blade systems and one or more axial flow blade systems, guide blade apparatus including one or more rings of guide blades for each of said axial ow blade systems,

thesingle or first of said rings of guide blades being disposed in close proximity to the outlet edges of and in radial continuation ofthe ring of moving blades of the radial flow blade systems l and having inlet passages situated at a less distancefrom said la'st moving blade ring than the distance between its outlet passages and the first ring of moving blades of said axial flow blade system.

6. In an elastic fluid turbine, in combination, one or more radial flow blade systems and one or more axial flow blade systems, the several blade systems being symmetrically arranged with respect to a central plane normal to the axis of rotation of the turbine, a xed partition arranged substantially in said plane and extending in radial continuation of the center of the last ring of moving blades of said radial flow blade system and dividing the space for flow of motive fluid between the radial flow blade systems and the axial flow blade systems into two entirely separated guide channels, and guide blade means for the axial flow blade systems attached to said partition.

7. In an elastic fluid turbine, the combination with one or more radial flow blade systems and one or more axial flow blade systems, of a guiding partition for elastic fluid arranged radially and centrally of the space between the radial 110W blade systems and the axial ilow blade systems, guide blade means for the axial now blade systems attached to said partition and radially arranged walls attached to the ends of said guide blade means opposite the ends attached 'to said centrally arranged partition.

8. In an elastic fluid turbine, the combination with one or more radial flow blade systems and one or more axial flow blade systems, of means for dividing the space between the radial now blade systems and the axial flow blade systems into two channels for guiding elastic fluid vin said space comprising guide blade lmeans for each channel, a centrally and radially disposed partition common to both of said channels and radially extending walls attached to said guide blade means.

9. In an elastic uid turbine, the combination of one or more radial flow blade systems and one or more axial flow blade systems, an elastic fluid guiding partition radially and centrally disposed in the space between the radial flow blade systems and the axial flow blade systems, an annular part forming a continuation of said partition and provided with port means to discharge therethrough moisture separated by condensation from the elastic fluid, said annular part provided with chamber means, and means for preheating water in said chamber means.

10. In an elastic fluid turbine, the combination of one or more radial flow blade systems and one or more axial flow blade systems, an elastic uidguiding partition radially and centrally disposed in the space between the radial flow blade systems and the axial flow blade systems, an annular part forming a continuation of said partition, .means for preheating of water, said annular part and preheating means being connected by port means to discharge therethrough moisture separated by condensation from the elastic fluid.

1l. In an elastic fluid turbine, in combination, a radial ow blade system, an axial flow blade system spaced therefrom and adapted to receive motive fluid exhausted from the radial ow blade system and guide blade means comprising a ring of guide blades in the space between said systems, said guide blades extending substantially axially of the turbine and having inlet edges in close proximity to and substantially parallel with the outlet edges of the blades in the last ring of moving blades of the radial ow blade system.

12. In an elastic fluid turbine, in combination, a radial ilow blade system, an axial flow blade system spaced therefrom and adapted to receive motive iluid exhausted from the radial flow blade system and guide blade means comprising a ring of guide blades in the space between said systems, said guide blades extending substantially axially of the turbine and having inlet edges in close proximity to and substantially parallel with the outlet edges of the blades in the last ring of moving blades of the radial flow blade system and said guide blades having greater width axially of the turbine than length in the general direction ofv flow of elastic huid past the guide blades.

13. In an elastic uid turbine, in combination, a radial flow blade system, an axial flow blade system adapted to receive the motive fluid exhausted from the radial flow blade system, said systems being spaced to provide an annular space radially outside of the radial flow blade system and axially to one side of the axial flow blade system and a ring of stationary guide blades having inlet edges in close proximity to and substantially parallel With the outlet edges of the outermost blades of the radial flow blade system, the radial extent of said guide blades being substantially less than the radial extent of said space and said guide blades discharging elastic fluid into the radially outer part of said space With rotational movement.

14. In an elastic fluid turbine, in combination, a radial ow blade system, an axial flow blade system adapted to receive the motive fluid exhausted from the radial ilow blade system, said systems being spaced to provide an annular space radially outside of the radial flow blade system and axially to one side of the axial flow blade system and a ring of stationary guide blades having inlet edges in close proximity to and substantially parallel with the outlet edges of the outermost blades of the radial ow blade system, the radial extent oi.' said guide blades being substantially less than the radial extent of said space and the outlet edges of said guide blades being angularly disposed with respect to the inlet edges thereof, whereby to make said blades longer in the direction of flow of elastic fluid at the side remote from the axial flow blades than at the side adjacent to the axial flow blades whereby to asn sist in directing elastic iluid. into the first of moving blades of the axial flow blade system.

ALF LYSHOLM.

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