Note: Descriptions are shown in the official language in which they were submitted.
2Q72~2
91R019
INTEGR~rED TURBINE ~N~ PUMP ~SSEMBLY
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W, R. Bissell
~, L. Stangeland
II~ObRWUD DF T~ r I ~
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1. ~ r ~ e~on
The present invention relates to high-speed turbopump
assemblies and more particularly, to an integrated turbine an~ pump
design whereby the conventional design having a pump or compressor
,~ section, a turbine section, and associated bearing and seal components
, 10 are eliminated in ~avor o~ a unitary turbopump assembly.
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2, of Related Qrt
Prior art turbomachinery provides inducer, axial flow, and
centrifugal type pumps or compressors which are coupled to an axial or
radial flow turbine as a source of power. rhe pumps can be single stage
or maltlstage depending on the discharge pressure or~head required and
the density of the~fluid belng pumped. The turbines can be single stage
or multistage and ~an be o~ an impulse or reaction type depending on the
energy level available in the working fluid. The pump and turbine can be
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~~` separate units connectQd together by a coupling for torque transmission
or can be mounted on a commor) sha~t. Typically, the rotor is an assembly
of numerous parts consisting of pump inducers and impellers, turbine
discs or wheels, bearing journals and dynamic seal mating rings; all of
S which are assembled together on a common shaft through splines or curvic
couplings and preloaded together through the use of retainer nuts and
bolts to make up the rotor assembly. The housing consists of numerous
parts, including inlets, interstage diffusers, volut~s, turbine
manifolds, nozzles, hearings, labyrinth seal, and dynamic seal; all
bolted together with the appropriate static seals to make up the
turbopump housing. The rotor components are assembled for balancing
purposes but then must be disassembled to facilitate assembly vf the
turbopump, resulting in relocation unbalance during reassembly of the
rotor.
15~ typical state of the art liquid hydrogen turbopwmp, of the
type discussed above, has a housing that penetratas the rotating
assembly, to a diameter less than that of either the pump impellers or
the turbine rotors, at lea~t four times between the first pump impeller
and the last turbine rotor. rhe reasons for these penetrations are (a)
2~ the diffuser type utilized, (bj the pump interstage flow path utilized,
and (c) the low speed limitations of conventional bearings and seals. ~s
a result, at least six major rotating assembly parts, and six major
; housing parts, are required to permit the unit to be assembled and
disassembled. In addition, the large depth of the penetrations results
in a rotating assembiy that is quite flexible and, therefore, is subject
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to operation in thQ ran~e of sevqral flexural critical speeds This
large number of parts combined with the critical speed limitations
results in a ~Init that is costly to assemble and maintain and that is
difficult to operate over a wide throttling range. In addition the
rotational speed limitations of the conventional bearings and seals
results in a unit that is relatively large and heavy.
For example U. S. Patent 4 482 303 of November 13 1984
provides a turbo~compressor apparatus having the turbine section and the
compressor section back-to-back. ~ stationary or non-rotating shaft
axially supported in the apparatus supports an anti-friction bearing
which in turn rotationally supports a rotor assembly which has a
turbine wheel disposed within khe turbine section and a compressor
impeller dispose~ within the compressor section.
U. S. Patent 4 260 339 of ~pril 7 1981 defines a turbo
compressor apparatus including housing means rotor means housed within
the housing means fixed shaft means anchorage means fixedly anchoring
the shaft means to the housing means and bearing means axially and
radially locating the rotor means for rotation with respect to the shaft
means.
Finally U. S. Patent 4 255 095 of March 10 lg91 ~escribes
a turbine-pump unit characterized in that the pump and the turbine are
coupled together at their high-pressure end.
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OBJEC S _F THE INVEN-_LON
,
~ ccordingly, it is an object of the present invention to provide a
simpli~ied turbo~)ump design typically hauing a single integral rotating
element and two major housing elements plus ducting.
~ nother object of the present invention is to prouide a turbopump
design hauing a very rigid rotating element whereby flexural critical
: speeds are eliminated from the operating speed range,
SUMM~RY OF THE INVENTION
~11 of these and other objects are achieued by the present
invention which provides a twrbopump assembly consisting of a first pump
section, a second pump section, and a turbine section. The objectives of
: a minimum number of parts, and a rotating element that is free of
flexural critical speeds, are achieued by designing to minimi~e the
number of penetrations of the rotating element by the stationary
housing, This is accomplished by (a) placing the centrifugal pump inlets
~: at the ends of the rotating element, (b) combining the bearing and seal
functions into single components that are placed at the same diameter as
-i the centrifugal pump impellers, (c) placing the pump flow diffusers and
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flow collectors at diameters grea-ter than those of the centri~ugal
2U impellers (d) placing the turbine rotor between the pump elements at a
diameter that approaches, or euen exceeds, that of the centrifugal pump
impellers, and (e) integrating the turbine inlet and exit manifolds and
~ ; the pump inlets and volutes into a two piece housing.
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; ` The forego.ing and other ohjects, features and aduantage~ of the
present inuention will become more apparent in light of the following
detailed description of the embodiments thereof as illustrated in the
accompanying drawings.
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For the purpose of` illu~trating the invention, there is ~hown in
the drawings embodiments which are p~esently pre~erred, it being
understood, however, that the inuention i~ not limited to the precise
arrangements shown.
Fig. 1 iS a cro3s-sectional oblique view of a turbopump assembly
as is known in the prior art,
fig. 2 is an end view of a turbopump assembly of the present
invention,
A Fig. 3 i3 a side elevational view along line 3-3 of Fig. 2j
Fig. 4 is a cross-sectional view taken along line 4-4 of Fig. 2,
Fig. 5 is a cross-~ectional view of one embodiment of the
turbopump assembly taken along line 5-5 of Fig. 4,
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Fig, 6 is an exploded view of the turbopump assembly of Fig. 4,
; ~ fig. 7 is ~ cros~-sectional view of a turbopump assembly having
~o ~Ingle~ stage centrifugal pump and a radial inflow turbine, utilizing the
present invention teaching3.
Fig. 8 is an end view along line 8-8 of Fig. 7, and
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Fig. 9 is a cross--sectional view of a turbopump a3sembly having a
single stage centriful3al pump and an axial flow turhine util;zing the
present inVQntion taachings.
~ET~ILED ~ESCRIPTION OF THE PREFERREo EMEODIMENTS
Referring now to the drawings wherein like numerals indicate like
elements there ix shown in Fig. 1 a turbopump assembly constructed in
accordance with the prior art.
fls depicted in Fig. 1 prior art turbopump assembly 10 is provided
with a forward three stage pump section 12 and an aft two stage turbine
section 14. Forward pump section 12 includes a fluid inlet 16 inducer
18 and three impeller stages 20. Common shaPt 22 is associated with
forward pump section 12 and aft turbine section 14 of assembly 10. ~ft
turbine section 14 is also provided with a turbine Pluid inlet 24
turbine fluid outlet 2~ turbine blades 28 and turbine disc 30. The
1~ method oP operation of turbopump assembly 10 is characterized by a
functioning of the aft turbine section 14 by the introduction of working
fluid via 24 which causes the ~unctioning of turbine blades 28 which in
turn rotate shaft 22. Rotating shaft 22 functions impellers 20 located
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: on shaft 22 within the pump section 12 of assembly 10 and induces fluid
to flow via fluid inlet 16 Into pump section 12. From pump section 12
~: the Pluid is transported out of section 12 as shown by the arrow at high
: pressure for further utilization.
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91RO19 2 0 7 2 2 4 2
With reference to the draw:ings Fig. 4 depicts a turbopump
assembly constructed in accordance with the present inventi.on and
designated generally as 40. Turbopump assembly 40 includes a first pump
section housing 42 and a second pump section housing 70 each of which
5 may be made of aluminum titaniam or high strength steel alloys or a
plastic material suitable for the design requirements of assembly 40. In
addition to housings 42 and 70 assembly 40 is further provided with
rotating shaft 51 as shown in Figs 4 and 6 having a largely cylindrical
constant diameter external surface
RotatRble shaft 51 is positioned within housings 42 and 70 and in
~; cooperation with said housings defines a first pump 43 within first pump
section housiny 42 and a second pump 71 within second pump section
housing 70 ~nd a center turbine 50 with manifolds 94 and ~6. In other
words if the shaft and housings of Fig. 6 were joined then as shown in
Fig 4 the composite struc-ture would provide a first or Porward pump 43
and an aft pump 71 having first pump section fluid inlet 44 and second
pump section inlet 72 respectively and a center turbine 50 with an inlet
manifold 36 and an exit manifold 94.
Referring again to Fig. 4 the first or forward pump generally
20 designated 43 includes an inlet 44 an inducer 46 an impeller 4~ a
diffu~er 54 and a volute 56. Internal manifolds 94 defined by an
. internal surface 64 (see Fig. 6) of the first pump section housing 42 and
an external surface 66 of shaft 51 embody the turbine exhaust manifolds.
In similar fashion second pump generally designated 71 includes inlet
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72 impeller 76 diffuser 78 and volute 80. Internal manifolds 86
defined by an interrlal surPaGe 98 of the second pump housirlg 70 and
external surface 100 of shaft 51 embody the turbine inlet manifold 86.
By this configuration first or forward pump 43 second or aft
pump 71 and center turbine 50 form an integrated turbine and dùal pump
turbopump conFiguration.
In order for working fluid to be processed by turbopump assembly
-the first pump section housing 42 includes fluid inlet 44 which
directs fluid past inducer 46 asso&iated with forward impeller hub 52 of
rotating shaft 51. The Porward impeller hub 52 also includes pump
impeller 48 attached thereto. Located within first pump section housing
42 is diFfuser 54. Diffuser 54 communicates with volute collector 56
which in turn is associated with fluid passage 58 which supplies
lubricating fluid to adjacent hydrostatic bearing/seal surfaces 59.
~ forward volute discharge 60 is formed proximate volute collector
56 and via interpump crossover 62 allows for fluid communication between
first pump 43 and second pump 71 defined by housing 42 housing 70 and
` rotating shaft 51.
.~ Second pump inlet 72 in the aft end of second pump section housing
.,;
20 70 as shown in Fig. 4 includes impeller hub 74 of shaft 51 second pump
impeller 76 second pump diffuser 78 and second pump volute collector
80. Fluid from voIute discharge 60 flows through interpump crossover 62
into in1~t 7i and second pu~p 71.
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~ s wi.ll be e~plained in greater detail hereinbelow ~olute
collector 80 communicates with second pump volute discharge 8Z (see Figs.
2 and 3). The turbine inlet 84 communicates with inlet manifold 86 and
stationary inlet no~zle vanes 88 attached to se~ond pump section housing
70 to supply the working fluid to the turbine rotor blades 9Z. ~ chamber
90 is defined by second pump section housing 70 and rotating shaft 51
Within chamber 90 as seen in Fig. 4 nozzle v~nes 88 are positioned
~ approximate to shaft rotor blades 92 which ~re att~ched to rotating ~haft
- 51. Chamber 90 also Forms a conduit between inlet manifold ~6 and the
turbine exit manifold 94 of the forward pump housing 92. Exit manifold
94 then communicates with manifold outlet 96 (see Fig. 3) which directs
the turbine working fluid out of turbopump assembly 40 to an end user
such as a rocket engine thrust chamber.
In operation a fluid such as liquid hydrogen is supplied from a
fuel system holding tank (not shown) to the first pump inlet 44 ~nd
; gaseous high energy fluid is supplied to the turbine inlet 84.
The pump fluid enters the Pirst pump section 43 through inlet duct
44 and passes into inducer 46 which enables the pump to operate at low
inlet pressure. Then the majority of the first pump section energy
input occurs in impeller 48. The excess kinetic energy in the flow
leaving the impeller is conuerted to static pressure in diffuser 54. The
flow is then collected in volute collector 56 and directed into
discharge ducts 60 which lead to pump section flow crossover ducts 62.
The crosso~er ducts then merge and direct the flow into inlet 72. ~ll of
z5 the second pump section energy input o~curs in impeller 76. From there
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the flow situat:ion :is dnalogous to that at the exit to the first pump
sec~tion impeller, i.e., the flow is diffused in dif~user 78, collected in
volute collector 80, and directed into discharge ducts 82 (which are
shown in Figures 2 and 3). From there, the fluid is directed to a user
system such as a ro~ket propulsion sy~tem.
~ portion, or all of that pump flow is returned, after being
- heated by combustiorl and~or heat -transfer, to drive the turbine. It
enter~ the turbine as a moderately high temperature gas through turbine
inlet ducts 84 (see Figure 4), and passes into the turbine inlet mani~old
1~ 86. Turbine nozzle blades 88 align that flow for efficient passage
through the turbine rotor blades 92, which convert -the kinetic energy in
- the nozzle exit flow to a torque that drives the two pump sections.
~fter leaving the rotor blades, the flow is collected in turbine exit
manifold 94, and delivered to turbine discharge ducts 9~ (see Figs. 2 and
3) From there, the flow is delivered, depending on the engine cycle,
either to the mai.n combustion chamber, or to a turbine exhaust thruster.
The rotating element is supported, in the radial direction, by
combined hydrostatic bearings/seals that are located on both sides of
both impeller exi-ts.
In conventional turbopumps, the rotor center of rotation is
established by radial bearings and the concentricity of -the i~peller
shroud and interstage seals must be maintained with respect to the
bearings. By combir)lng the function of the bearings and seals into the
~; hydrostatic bearings located on both sides of the impeller discharge,
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91R019 2 0 7 2 2 ~ 2
c~oncents~icity conts~ol between bearings and seals is eliminated and normal
di-fferential pressure leakage is uti:llzed to provide the hydrostatic
bearing stif~ness and damping.
For the first pump section 43, the first of these combined
bearings is located in the radial concentric space between the
ind~scer/impeller shroud 49 ans~ housing 42, and the second of tl)ese
combinecs bearings i8 located on the other sisJe of impeller 48, and i5 fed
by flow that passes from volute collector 56 to secondary bearing supply
58. Similar combined bearirlgs support the radial loacss in the second
pun)p section 71. rhe axial thrust loads are pressure balancec.~ by
thebalance piston flow that is delivered to the radial face outside of
ind(scer 46 through the balance piston flow duct that passes from seconcs
pump section volute 80 to the aforementioned radial face~
With this arrangement of turbopump components, it is apparent that
the housirlg consi6ts of only three parts; first pump section housing 42,
second pump section housing 70, and pump section crossover duct 62. The
lack of housing penetration into rotating element 51, to diameters less
than those at the tips of impellers 48 and 76, permits this great
simplification. It also perss~its the rotating assembly to consist of
only one part. Finally, it maximizes the diameter of that rotating
assembly, thareby eliminating Plexural critical speeds from the turbopump
operating range~
Qlternate turbopump config~sratlons to which this princisple is
applied are illustratea: in Figs. 7, 8, and 9. These configurations
2~ differ from that of Fig~ 4 ~n that they only have one pump section (or
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stage) and, therefore, ha\/e their turbines on the other end of the shaft
rather than in the middle. rhe configuration illustrated in Figs. 7 and
8 ha5 a radial inflow turbine, and that of Fig. 9 has an axial flow
turbine. However, both configurations utilize the combined hydrostatic
bearings and seals, and the principle of no housing penetration to a
diameter of less than that of the pump impeller, to obtain the same high
degree of simplicity, and the same resistance to critical speeds, as were
obtained with the conPiguration in Fig. 4.
Similarly, as in the turbopump assembly depicted in Fig. 4, the
10 turbopump a55emblie5 shown in Figs. 7-9 provide an inside diameter of the
i respective diffuser, collector and nozzle equal to or greater than the
turbopump impeller tip. In addition the assemblies of Figs. 7-9, as with
the embodiment of Fig. 4, provide a minimum diameter, for each assembly
diffuser, collector and turbine stators, equal to or greater than the
impeller tip terminus.
In this m~nner the turbopump assemblies (Figs. 1-9) exhibit a
housing configuration that seleti~ely pre~ludes penetration by the
`. aforementioned components into the assembly shaft of the turbopump
as~emblies.
~ 20 Referring to Figs. 7 and 8, fluid flow of the type discussed
; ~ above, enters the pump throu~h inlet 100 and passes through inducer 102,
which enables the pump to operate at low inlet pressure. Then, the bulk
of the pump energy inpu-t to the Flow occurs in impeller 104. Next, the
flow passes into radial diffuser 106, where the excess kinet~c energy is
con~erted to static pressure. From there, the Flow passes into volute
collector 10~, which directs it into the pump exit ducts 110.
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To drive this pump turbine drive gas enters the turbine through
turbine inle-t ducts ll2 and passes into the turbine inlet manifold 114~
It is directed at radial inflow turbine rotor 118 at the appropriate
angle by inlet noz~les 116 (see Fig~ 8)~ ~s the flow passes radially
.~ 5 inward rotor 118 converts the kinetic energy in the drive gases into
mechanical energy to drive the pUIl)p on the o-ther end of shaft 122. ~rhe
spent drive gases then exit the turbine axially through duct 120~
; Shaft 122 which has the pump impeller on one end and the turbine
rotor on its other end is supported by combines hydrostatic bearings and
seals 128 130 and 132 that are located at the same diameter as that of
the pump impeller tip and the turbine rotor tip. Through this
arrangement the configuration in Figures 7 and 8 requires only three
parts the shaft/rotor/impeller 122 and housing parts 124 ~nd 126. It
thereby ach;eves the same simplicity and ruggedness that was exhibited by
the cor~fisurAtion shown in Fig. 4.
~lso shown in Fig~ 7 is an annular gap 125 which thermally
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isolates the higher temperature turbine from the lower temperature pump
during operation.
In the configuration shown In Fig. 9 the pump function is
identical to that just di5cussed. The Plow enters the pump through inlet
; 200 and passes through inducer 202 which enables the pump to operate at
low inlet pressure. Then the bulk of the energy input to the flow
~ occurs in impeller 204. Next the flow passes into radial diffuser 206: where the excess kinetic energy is conuerted to static pressure. From
there the flow passes into volute coll~ctor 208 which directs it into a
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pump exit duct (not illustrated).
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To dri~e this pump trle turbine drive gas enters the turbine
throùgh a turbine inlet duct (not shown) and passes into turbine inlet
; manifold 210 which aligns it and directs it into a~ial turbine rotor
blades 212. These turbine rotor blades expand and convert the gas energy
into meshanical energy to dri~e the pump through shaft 218. Upon leaving
the rotor blades the gases are diffused and turned axially by stationary
stator vanes 214. The spent gases then leave the turbine through e~it
~u~.t 216.
Shaft 218 which has the pùmp impeller on one end and the turbine
rotor on its other end is supported by combined hydrostatic bearings and
~ seals 224 226 and 22~ that are located at the same diameter as that of
; the pump impeller tip. Through this arrar)gemwent the configuration of
; Fig. 9 consists of three parts the shaft/rotor/impeller 218 and housing
sections 220 and 222.
15By conlbining the bearing and seal functions into a single unit and
placing them at the same diameter as that of the pump impeller tip(s) by
plAcing the pump inlet(s) at the end of the shaft and by making the
diameters of the pump ~iffuser/collector and the turbine manifold nozzle
equal to or greater than that of the pump impeller tip(s) the following
.20 features result:
(a) The housing that contains the diffusers collectors
manifolds and nozzles can be made of only two parts that when unbolted
c~n be slipped off the two ends of the rotating assembly.
: : (b) The rotating assembly that contains the shaft the
pump impeller(s3 and the turbine rotor can be made of only one part.
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(c) The above features translate int~ an o~erall turbopump
assembly that consists of only four parts if there are t~Jo pump sections
(as in Figure 4) and only three parts if there is one pwmp section (as
; in Figures 7 and 9)
(d) The minimum diameters of the rotating assembly are
maximized thereby minimi~ing the possibility of ~peratirlg at ~le~ural
critical speeds which in twrn greatly enhances operational stability
range and reliability.
The present in~ention may be embodied in other specific forms
without departing from the spirit or essential attributes thereof and
accordingly reference showld be made to the appended claims as
indicating the scope of the in~ention~
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