US1601614A - Turbine - Google Patents

Description

- 1,601;6l4 R. w. FLEMING Sept. 28 1926. I

TURBINE Filed Sept. 23

1925 5 Sheets-Sheet 1 INVENTOR. dQceaZWZ'Zeva Sept. 28 1926. 1,601,614

R. w. FLEMING TURBINE Filed Se t. 25, 1925 5 Sheets-Shleet 2 g M r 8 I vwemtoz 1% sa 91- 96k Sept. 28 1926.

R. W.- FLEMING TURBINE File pt. 23, 1925 5 Sheets-Sheet 09 uxumbt no EOFOE 10 \g iorcuFom m0 zocbwma PKWIWRMMMEDP NZ: EWFZUU 1; WM A TTORNEY.

Sept. 28 1926.

v R. w. FLEMING TURBINE Filed Sept. 23, 1925 5 Sheets-Sheet 4 BY Q OKL ATTQRNEY,

INVENTOR. fizelfmz Sept. 28 1926.

R. W. FLEMING TURBINE Filed p 1925 5 Sheets-Sheet s INVENTOR.

$0.567? my 210*? r ATTORNEKF 1,601,614 PATENT OFFICE.

ROBERT WALTON FLEMING, OF THE PLAINS, VIRGINIA.

TURBINE Application filed September 23, 1925. Serial No. 58,201.

This invention relates to steam turbines. Heretofore steam turbines have, in general, been of two characters. In one case the rotative effect has been produced by the inertia of movement of one or more steam jets striking against suitably designed buckets,

such turbines being usually called impulse In the other case alternate rotor and stator elements, each having amultiplioity of blades have been employed, the reaction due to expansion and change of direction of flow of the steam producing the r0- tation of the rotor, such turbines being commonly known as reaction turbines.

It is well known that, in moving a properly formed aerofoil, such as an airplane wing, through the air a partial vacuum is produced above the aerofoil as well as pressure beneath and the upward tendency due to this partial vacuum produces what is known as lift. (Practical Aviation by Kayward, American Technical Society, Chicago, Illinois, 1919.)

One principal object of this invention is to provide a turbine having blades and general construction designed to utilize, as fully as possible, this lift.

This force called lift is generated by placing in a steady fluid flow 'a blade so designe in cross-section and so placed with regard to the flow that the pressure above the top of the blade is diminished while that below ,the blade is increased. There are then forme two areas of influence. The one above the blade of low-pressure or suction, an that below the blade of thigh-pressure. To secure the best results consecutive and complementary blades must be so shaped and placed that these areas do not materially interfere with each other.

A second object of this invention is to increase the efficiency of a turbine by so designing, spacing, and placing the blades with regard to'the steam flow and to one another that, the low-pressure areas above the blades be utilized and not interfere with the high areas below the blades or be disturbines.

pressure turbed by the blades themselves. Also that the losses due to eddy-currents, tip clearances, drag, and friction be reduced to a minimum, while at the same time producing the maximum useful work possible from the steam.

Wherever, in this application, any one of the words steam, air, water, or any other gas or liquid or fluid substance is used it is to be taken to mean not only itself but also any one or more of the above named substances used to convert its potential power into work or assisting therein, by means of blades made fast to a rotor and acted upon by the substance.

With the above and other objects in view as will be hereinafter apparent, the invention consists in general of certain novel details of construction and combinations of parts hereinafter fully described, illustrated in the accompanying drawings and specifically claimed.

In the accompanying drawings like characters of reference indicate like parts in the several views, and:

Figure 1 is a longitudinal median section through a typical turbine constructed in accordance with this invention.

Figure 2 is an enlarged detail view of a portion of the inlet end of Figure 1, certain blades being omitted.

Figure 3 is a greatly enlarged perspective of one of the turbine blades removed from the rotor.

Figure 1 is an end view of the turbine from the inlet end thereof, the steam chest having been removed.

Figure 5 is a section on the line 5-5 of Figure 1.

Figure 6 is a Figure 5 the view being detail showing a portion of enlarged the better (1 to show the blade mounting.

Figure 7 is a diagram showin the crosssectional layout of one of the b ades.

Figure 8 is a partially diagrammatic view showing the arrangement of the blades'between the inlet and outlet ends of one stage in a turbine constructed in accordance herewith, the view being partially broken away to permit enlargement of the scale used.

Figure 9 is a diagrammatic view showing how the blades may be located relatively to each other and to the steam flow.

In the embodiment of the device here shown a three stage turbine has been illustrated as typical of the invention but it is to be understood that the number of stages may be increased or diminished according to the service to be performed without in any way affecting the principles of the invention.

Again, as will be seen later, certain angular relations between the entering steam and the blades as well as between the blades themselves are shown. In like manner these is provided a shaft 10 which is, of course,

supported in suitable bearings one of which is shown at 11. On this shaft, for each stage of the turbine, there is fixed thereto a hub 12 which may carry plates 13, as shown in Figures 1 and 2, or spokes 14, as shown in Figure 5. .On the peripheries of these plates or the outer ends of these spokes, as the case may be, is mounted a frusto-conical rim 15 constituting the inner shroud or support for the inner ends of the turbine blades as will.

be presently explained. In the frusto-conical formation of this rim or inner shroud the taper of the frusto-cone is inwardly from the inlet end to the outletend. The rim, hub and connecting members plates or spokes thus constitute a rotor wheel having a frusto-conical periphery tapering inwardly from the inlet end to the outlet end, at such an angle, slope or curve as will give the best steam expansion with this particular arrangement of blade as herein set forth.

Spaced from the rim 15 is an outer rim or shroud 15 likewise of frusto conical form 7 but tapering in the opposite direction also designed to give the best steam expansion. That is to say the outer shroud tapers out -wardly from the inlet to the outlet end. By

.this means there is provided an annular space between the rims increasing in crosssectional area from the inlet to the outletend of the turbine.

An exception is to be noted to this in respect to the first stage wherein the inner and outer shrouds at the inlet end are flaredaway from each other to produce the equivalent of a Venturi effect. This is not necessary however.

At the inlet end of the turbine is provided, a steam chest 18 which carries the nozzle supporting flange at the end adjacent the rotor, which consists of inner and outer concentric rings 19 connected by diagonally disposed partitions 20.. Similarly, between each adjacent pair of stages there are provided nozzle rings each consisting of inner and outer rings 21 connected by diagonal partitions 22. At the outlet end of the turbine there is provided the usual exhaust chamber 23. 7

It will beobvious that suitable packing arrangements will be made in the construction of the device but it is not thought necessary either to show or describe anysuch as these details form no part of the present invention.

All of the blades 24 are secured to both the inner and the outer shroud by fastenings 25 which may be of any preferred type. In this way the nozzle rings and easing form the stator while the shaft and the parts carried thereby form the rotor.

There will now be considered certain special features of the invention and first may be mentioned the peculiar cross sectional contour of the rotor blades. Each of these blades resembles in cross section the wing of an airplane and as typical of the manner in which such a cross section may be laid out reference is had to Figure 7. In this figure it will be seen that is divided into ten equal parts and the greatest camber 'of the blade is at approximately 30% of this chord from the leading edge a The leading edge along the chord line 02'. being that part .of the blade farthest advanced up stream of the fluid flow. The nose of the blade is rounded and adjacent the leading edge on the under or pressure side of the blade a reverse camber f of small radius of curvature is formed just back of such,edge. This reverse camber merges into a positive camber which again merges into a relatively long reverse camber h of relatively large radius of curvature near the trailing edge 2', the latter being the point where the upper and lower blade surfaces meet. The upper or lift side of the blade has a continuous camber K. Such a blade closely resembles in cross section the United States Army 1919. Of course other be used but all such will and will be generically described as such, meaning thereby a section wherein lift is developed by partial vacuum on the upper side of the blade and pressure on the under side of the blade. These vacuum and pressure areas are indicated at a: and 2/ respectively in Figure 8. The dotted lines indicatingapproximately the boundaries of these areas.

An important feature of the invention is illustratedparticularly in Figures 8 and 9 blade sections may be of aerofoil type the chord distance ab I standard wing curve No. 5 of and this feature relates to the peculiar arrangement of the blades so that the steam or other propelling fluid acts on these blades in such manner as to produce a substantially equal pressure on the pressure side of each blade and a substantially equal lift on In addition, the

shown dotted. Next we angle we increase the line of the blade interference of the vacuum area on the top of the blade.

In other words, my blades are so placed around the periphery of the rotor wheel that complementary blades will not interfere with one another, each succeeding row of blades being also placed along the line of fluid flow so that the blades will be in the smoothest flow possible coming from the preceding row of blades. that no so-called guide blades are used between the blades in this case and redirec-' tional blades only used b the successive stages. As an example 0 the manner in which the positions of these blades are determined for this purpose let us assume as shown in Figure 9 that I have a turbine which we desire to have a blade peripheral linear velocity of 500 foot seconds represented by the length and direction of line dm. This force is in a plane perpendicular to the shaft center line of the turbine, as decide that we wish the total resultant force which acts on the blade to be at an angle of 45 degrees with the planeof rotation of the blades. This resultant force is represented by line dq making an agle of 45 degrees with dm. This angle gdm may vary in accordance with amount of the component of dq which it is desired to have acting along line dm, this component being do. By decreasing the do and decrease g0 and vice versa. In this particular case however we chose .45'degrees. The resultant force dq is made up of two forces, one parallel to the chord of the blade and represented by sq and called drag, he other perpendicular to the chord of the blade represented by ad and called lift. Sq and 8d are two sides of a parallelogram of forces and gd is the resultant, angle sdg being about 5 degrees in the case of the blade form chosen. Now we know that the lift sd is perpendicular to the blade chord (i. e., the blade chord in Figure 7), so we can now lay off line ode at 90 degrees with sd and for the convenience of construction assume that the forces on the blade act through the leading edge and thereby lay off the shape marked Blade with its nose at d and its chord along de.

We have chosen a blade form which gives the best results, or in other words, the maximum lift/drag ratio at an angle of attack of plus 10 degrees, dl making an angle of lus 10 degrees with cllord edo. It is observed that this angle of attack of the blade may vary between minus 10 degrees and-plus 30 degrees according to the conditions and in order to prevent the effect called burbling, or in other words, the

formation of 'eddy currents, vortices or the reduction of a bow wave, and at the same time to obtain the maximum lift/drag ratio It will be noted from the preceding will take successive positions attack, the theoretical determination of therefore we lay olf line' .entrance steam. In this case it will be with the plane of rotation of the blades, or in other words of the rotor wheel.v

In order to place blade de we advance along the rotor wheel making the distance dd equal the chord length de and lay off chord de parallel to de and locating the leading edge of the blade at d.

In order to lay off blade d 'e" extend chord de indefinitely. Erect ed perpendicular to de at 6. Draw rd parallel to dm and so that rd equals one half chord dc, then draw d"e' so that it will make 5 degrees with line ode, or in other words so that the chord of blade d"e' is rotated 5 degrees clockwise from chord of blade de. d is then the nose of the new blade and d 6 equals dc on its chord, which gives the set of the next row blades. In like manner the blades may be spaced and each row may be angularly displaced 5 degrees clockwise row. By continuing found that the blades as illustrated in Figure 8. As the steam or other fluid leaves the last row of blades, it is directed through another set of nozzles shown' at 21 in Figure 8 having the same inclination relthis process it will be ative to the blades of the second stage of the v rotor as the nozzles at 19 have to the blades of the .first stage.

It is to be understood that this is only one typical example in the manner in which these blades may be layed out and positioned, the-example being givenwith certain assumption including certain blade peripheral lineal velocity of 500 foot seconds.

is of-course obvious that the same process ma be used with other velocities as well as.

other nozzle angles anddirections plf t e ro er velocities and angles being attained wit in t e well known manners set forth in the various text books on'a'viation and aerodynamics. And it. is not accordingly deemed necessary to enter further into the theory involved since the action of known visc'ous fluids on aerofoils-is well known.

.As the fluid enters the inclined nozzles 20 it is 'ven a direction of flow and encounters the rst series of blades atthe left as shown in Figure 8.. Some of the fluid passing above and some beneath. The upper surfaces of the blades are of larger area than the lower surfaces. This together with its shape will cause a reduced pressure on the upper side of the blades and an increased pressure below the blades. These pressures being diagrammatically illustrated by the dotted curve lines in Figure 8 the position and shape of the blades being such that these pressure areas interfere as little as possible with each other. After the fluid has passed in succession over all the series of blades in the first stage of the rotor its direction is changed by the stator nozzles22 and delivered to the second stage rotor and its action'is repeated and so on through all the turbine stages. I

Having thus described the invention, what is claimed as new, is: I 1. In a turbine, a rotor, blades attached thereto and arranged in successive rows, the second row taking the fluid from the first row, each blade having an aerofoil cross section and set at an angle of attack ofthe stream flow such that a partial vacuum Will be formed on its inactive surface and a pressure on the active surface. -2. In a turbine, a rotor, a plurality of cir cumferential rows of turbine blades, the forward row set at an angle of attack of the stream flow of between minus 10 30 and the following row or rows having their cord lines set at an angle to the cord lines of the preceding row. 3. A turbine comprising a rotor in a plurality of stages,'each stage having a plurality of'circumferential rows of blades having an aerofoil cross section with the leading row of blades on each stage set at an angle of attack of the stream flow and each of the succeeding circumferential rows of blades set at an angle of attack similar to that of the preceding row whereby a smooth stream line flow from one row of blades to the succeeding row is obtained.

4. A turbine blade having \an aerofoil cross section, and set at an angle of attack of the stream flow of between minus 10 degrees and plus 30 degrees, rect a stream of elastic fluid against said blade. v

5. A turbine'blade having a cross sectional contour similar to the standard Army aeroplane wing designed to produce a partial vacuum on its inactive surface under the influence of a stream of elastic fluid impinging upon'its active surface, and means to direct a stream of elastic fluid against said blade. I

6. A turbine blade having a cross sectional contour similar to the standard Army aero plane Wing designed to produce a partial vacuum on its inactive surface and a pressure on its active surface under the influence of a stream of elastic fluid impinging upon its active surface, and means to direct and plus and means to diing an aerofoil cross section, the blades of each successive row having their chord lines set at successively greater angles to the chord lines of the first row.

9. In a turbine, a rotor including a series of circumferential rows of blades each having an aerofoil cross section, the blades of each row having their chord lines set at an angle to the chord lines of the preceding row and offset circumferentially to the blades of said preceding row. I

10. In a turbine, a rotor including a series of circumferential rows of blades each having an aerofoilcross section, and a steam chest having a series'of angularly disposed nozzles leading therefrom and arrangedto direct elastic fluid against the first row of said blades.

11. In a turbine, a rotor including a series of rows of blades each having an aerofoil cross section, the blades of each row having their chord lines set at an angle to the chord lines of the preceding row, and a steam chest having a series of angularly disposed nozzles leading therefrom and arranged to direct elastic fluid against the first row of said blades.

p 12. In a turbine, a rotor including a series of rows of blades each having an aerofoil cross section, the blades of each row having their chord lines set at an angle to the chord lines of-the preceding row and offset circumferentially. to the blades of said preceding row, and a steanrch having a series of angularly disposed les leading therefrom and arranged to direct elastic fluid against the first row of said blades.

13. In a turbine, a rotor including a-series of rows of blades each having an a'erofoil cross section, the blades of each row havin their chord lines set at an angle to the chord lines' of the preceding row, the angles at which each row of blades is set with reference to the angles of the preceding row being such as to produce equal effects on each row ofblades.

14. In a turbine, a rotor including a series of rows of blades each having an aerofoil cross section, the blades of each row having their chord lines set at an angle to the chord lines of the preceding row, the angles at which each row of blades is set with reference to the angles of the preceding row being such as to produce a smooth stream line flow from one row of blades to the succeeding row.

15. In a turbine, a rotor including a series of rows of blades each having an aerofoil Cal cross section, the blades of each row having their chord lines set at an angle to the chord lines of the preceding row and offset circumferentially to the blades of said preceding row, the angles at which each row of blades is set with reference to the angles of the preceding row being such as to produce equal effects on each row of blades.

16. In a turbine, a rotor including a series of rows of blades each having an aerofoil cross section, the blades of each row havin their chord lines set at an angle to the chor lines of the preceding row and offset circumferentialy to the blades of said preceding row, to cause a smooth stream line flow from one row of blades tov the succeedingrow.

17. In a turbine, a rotor including a series of rows of blades spaced circumferentially of the turbine and each having an aerofoil cross section arranged to produce a vacuum area on the inactive side of the blade and a pressure area on the active side of the blade, the circumferential spacing of the blades in each row being such as'to prevent material interference between the vacuum and pressure areas, all blades of each stage of the turbine being mounted on a common shroud. 18. In a turbine, a rotor including a series of rows of blades spaced circumferentially of the turbine and each having anaerfoil cross section arranged to area on-the inactive surface of the blade and a pressure area on the active surface of the blade, the circumferential spacing of the blades in each row being such as to prevent material interference between thevacuum and pressure areas, the blades of each row having their chord lines set at an angle to the chord lines of the preceding row.

19. In a'turbine, a rotor including a series of rows of blades spaced circuinferentially 'of the turbine and eachlhaving an aerofoil cross section arranged to produce a vacuum area on the inactive side of the blade and a pressure area on the active side of the blade, the circumferential spacing of the blades in each row being such as to prevent material interference between the vacuum and pressure areas, the blades of each row having their chord lines set at an angle to the chord lines of the preceding row and oil'- set circumferentially to the blades of said preceding row. i

20. In a turbine, a. rotor including a. series of rows of blades spaced circumferentially produce a vacuum of the turbine and each having an aerofoil cross section arranged to produce a vacuum area on the inactive side of the blade and a pressure area on the active side of the blade, the circumferential spacing of the blades in each row being such as to prevent material interference between the vacuum and pressure areas, and a steam chest having a series of angularly disposed nozzles leading therefrom and arranged to direct elastic .fluid against the first row of saidblades.

21. In a turbine, a rotor including a series of rows of blades spaced circumferentially of the turbine and each having an aerofoil cross section arranged to produce a vacuum area on the inactive side of the blade and a pressure area on the active side of the blade, the circumferential spacing of the blades in each row being such as to prevent material interference between the vacuum and pressure areas, the blades of each row having their-chord lines set at an angle to the chord lines of the preceding row, and a steam chesthaving a series of angularly disposed nozzles leading therefrom and arranged to direct elastic fluid against the first row of said blades.

22. In a turbine, a rotor including a series of rows of blades spaced circumferentially of the turbine and each having an aerofoil cross section arranged to produce a vacuum area on the inactive side ofthe blade and a pressurearea on the active side of the blade, the circumferential spacing of the blades in each row being such as to prevent material interference between the vacuum and pressure areas, the blades of each row having their chord lines set at an angle to the chord lines of the preceding row, the angles at which each row of blades is set with reference to the angles of the preceding row being such as to produce equal effects on each row of blades. a

1 23. In a turbine, a rotor including a series of rows of blades spacedcircumferentially of the turbine and each cross section arranged to produce a vacuum area on the inactive side of the blade and a pressure area on the active side of the blade, the circumferential spacing of the blades in each row being such as to prevent material interference between the vacuum and pressure areas a smooth stream line flow from one row of blades to the succeeding row.

In testimony whereof he aifixes his signature.

having an aerofoil

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