Topics considered include: low-pressure oxidizer turbopump; low-pressure fuel turbopump; high-pressure oxidizer turbopump; high-pressure oxidizer turbopump turbine; high-pressure fuel turbopump; and SSME propellant flow schematic

Guinzburg, A.

English

NASA Technical Reports Server

E41000
RSS-8559-1-1-1
SPACE SHUTTLE TECHNICAL MANUAL
SSME DESCRIPTION AND OPERATION
( INPUT DATA) //J ._',
,,?i," / 7_--_
SPACESHUTTLEMAINENGINE
PARTNUMBERRSO01001
ROCKETDYNE DIVISION
ROCKWELL INTERNATIONAL CORPORATION
02602
THIS PUBLICATION REPLACES E41000/RSS-8559-1-1-_1
DATED 20 DECEMBER 1976
PREPARED AND PUBLISHED FOR NATIONAL AERONAUTICS
AND SPACE ADMINISTRATION UNDER
CONTRACT NAS8-27980,DPD NO.341,DR NO.LS-O90-1
7JULY 1977
https://ntrs.nasa.gov/search.jsp?R=19990041880 2020-06-18T00:59:15+00:00Z
E41000
RSS-8559-1-1-I
15. LOW-PRESSURE OXIDIZER TURBOPUMP
The low-pressure oxidizer turbopump (LPOTP) is an axial-flow pump driven by a six-stage turbine that is powered by
liquid oxygen. During engine start and mainstage, the LPOTP maintains sufficient pressure to the high-pressure oxi-
dizer turbopump (HtK)TP) to permit the HPOTP to operate at high speeds without an inducer and without cavitation even
in the worst case of engine inlet conditions. Turbine-drive fluid is tapped from the HPOTP discharge and, after power-
ing the turbine, is injected into the pumped fluid through a port between the turbine discharge and pump discharge
volutes. The combined flows are then routed to the I_.POTP inlet. Since the pumped fluid and turbine drive fluid are
both liquid oxygen and the LPOTP is located upstream of the oxidizer valves, the requirement for dynamic seals,
purges, and drains has been eliminated.
The rotor is supported by two liquid oxygen-cooled halt bearings. The turbine-end bearing coolant flow path is from
the last stage of the turbine, through the bearing, hollow rotor, radial holes in the rotor, and to the inducer discharge.
Coolant for the inducer-end bearing is from the turbine inlet, through the rotor labyrinth seal, through the bearing,
and to the inducer discharge.
A redundant-element, magnetic-type speed transducer is installed on the turbine end of the turbopump housing.
Access ports in the vehicle duct allow periodic inspection of the inducer blades for damage. Inspection is performed
with a fiber optic borescope.
The LPOTP is a line replaceable unit and has an approximate overall dimensional envelope of 18 by 18 inches.
INLET
FLANGE _
INLET
SLEE'
TURBINE TMP
DISCHARGE
VOLUTE
DISCHARGE
VOLUTE
ROTOR SPEED
TRANSDUCER
INDUCER-END
-TURBINE END
BEARING
ROTOR LABYRINTH SEAL TURBINE INLET
MANIFOLD
LSS-EC-P-42A
1-17
"E41000
RSS- 8559- I-1-1
16. LOW-PRESSURE FUEL TURBOPUMP
The low-pressure fuel turbopump (LPFTP) is an axial-flow pump driven by a two-stage turbine that uses gaseous
hydrogen (GH2) as the power medium. During engine start and mainstage operation, the LPFTP maintains sufficient
pressure to the high-pressure fuel turbopump (HPFTP) to permit the HPFTP to operate at high speeds without an
inducer and without cavitation, even in the worst case of engine inlet conditions. The turbine is driven by GH 2 from
the main combustion chamber (MCC) coolant outlet manifold.
The inducer and shaft axe supported by three liquidhydrogen-cooled (LH 2) bailbearings. The bearing coolant is the
leakage across the inducer discharge labyrinth seal. The coolant flows through the pump end bearings and turbine
bearing and is returned to the pump inletthrough passages in the shaft, beaxing bearing spacer, sad i,ducer.
Three shaft seals are used to control leakage between the pump and turbine before engine start and during operation.
Before engine start, leakage from the pump intothe turbine is prevented by a spring-loaded-closed, prope11.-.nt
pressure-acttmted-open, lift-offseal. During engine startthe seal nose is separated from its mate ring when
increasing fuel pressure overcomes the spring force. A positive separation between the seal nose end mate ring is
maintained untilengine shutdown when fuelpressure decreases below spring force. During operation, leakage from
the turbine into the pump is minimized by the pump and turbine seals.
A redundant-element, magnetic-type speed transducer is installed in the pump volute to monitor shaft speed.
Access ports in the vehicle duct allow periodic inspection of the inducer blades for damage. Inspection is performed
with a fiber optic borescope.
The LPFTP is a line replaceable unit and has an overall dimensional envelope of approximately 18 by 24 inches.
INSULATION
AND SHIELD
TURBINE INLET MANIFOLD
INDUCER
PUMP END
BEARINGS
TURBINE
DISK
SHAFT
TURBINE
SEAL
LIFTOFF
SEAL
PUMP SEAL
INLET FLANGE
INDUCER
LABYRINTH
SEAL
PUMP DISCHARGE VOLUTE
TURBINE BEARING
PUMP HOUSING TO
TURBINE HOUSING SEALS
1-18
LSS- EC-P-43A
O17. HIGH-PRESSURE OXIDIZER TURBOPUMP
The h_h-pressureoxidizerturbopump(HPOTP) consistsoftwosingle-s_ecentrUngalpumps ona common sh_t
that are directly driven by a two-stage hot-gas turbine. The main pump receives oxidizer from the low-pressure
oxidizer turbopump (LPOTP) and supplies oxygen at an increased pressure to the LPOTP turbine, the heat exchanger,
the preburner pump, and the thrust chamber injector. The preburner pump further increases the pressure to the
level required by the oxidizer preburner (OPB) and fuel preburner (FPB). The turbine is powered by hot gas
(hydrogen-rich steam) supplied by the OPB. Mixing of oxidizer and hot gas is prevented by seals, a purge, and
drains. Two duplex sets of liquid oxygen-cooled ball bearings support the rotating parts. The HPOTP is flange
attached to the hot-gas manifold (HGM) and is canted at a 10-degTee angle out from the" engine centerline. The HPOTP
is a llne replaceable unit (LRU) with an overall dimensional envelope of approxlmately 24 by 36 inches.
The HPOTP main pump has a single inlet with a 50-50 flow split into a double-entr_ common outlet impeller. Liquid
oxygen enters the main pump through the main pump housing where the flow split is made. Inlet vanes direct the flow
to the impeller inlet guide vanes, which in turn direct the flow to the impeller inlets. The impeller has four full and
four partial blades in each half. After passing through the impeller, the flow is redirected into the discharge volute
by diffuser vanes.
Turbopump shaft bearings are cooled by liquid oxygen from the preburner pump. Coolant for the preburnsr-end bear-
Ings is through the preburner pump impeller hub labyrinth seal, through the bearings, and to the main pump impeller
inlet. The turblne-end bearings coolant is through the preburner impeller bolt, through the hollow shaft, through the
bearings, and to the main pump impeller inlet. Pump shaft axial thrust is balanced in that the double-entry main
impeller is inherently balanced and the thrusts of the preburner pump and turbine are equal but opposite. Residual
shaft thrust is controlled by a self-compensating, nonrubbing, balance piston function by using the main impeller seal
leakage flows and controlling the pressure on the impeller shrouds by orifices at the impeller discharge tips. Mixing
of oxidizer and turbine gas is prevented by a dynamic shaft seal package that is between the main pump and the turbine.
The seal package consists of an oxidizer labyrinth .seal, a hydrodynamic primary oxidizer seal, a pressure-actuated
controlled-gap intermediate seal, and two controlled-gap turbine hot-gas seals. Drain cavities with overboard drain
lines are located between the primary oxidizer seal and the intermediate seal, between the intermediate seal and sec-
ondary turbine seal, and between the secondary and primary turbine seals. To further ensure against the mixing of
oxidizer and turbine gas, a helium purge is applied between the elements of the intermediate seal during engine opera-
tion.
The preburner pump has a single-entry impeller that discharges oxidizer through diffuser vanes into the discharge
volute. The preburner pump housing is flange-mounted to the main pump housing. ImpeLler seals interface with laby-
rinths cut in the outside diameter of the impeller shroud and hub to minimize leakage back to the pump inlet and control
the flow for cooling the preburne r pump-end bearings.
FROM LOW-PRESSURE
OXIDIZER TURBOPUMP
MAIN OXIDIZER PUMP
PREBURNER
OXIDIZER
'TO
, HOT-GAS
MANIFOLD
I_GH- PRESSURE OXIDIZER
TURBOPUMP TURBINE
FROM
HIGH-PRESSURE
OXIDIZER
TURBOPUMP
DISCHARGE
FROM
OXIDIZER
PREBURNER
TO FUEL PREBURNER AND
OXIDIZER PREBURNER
OXIDIZER VALVES
HOT-GAS MANIFOLD ATTACHING FLANGE
PREBURNER OXIDIZER PUMP INLET,
LOW-PRESSURE OXIDIZER TURBOPUMP
TURBINE,
HEAT EXCHANGER, AND MOV
E41000
RSS-8559-1-1-1
18. HIGH-PRESSURE OXIDIZER TURBOPUMP TURBINE
The high-pressure oxidizer turbopump turbine is powered by hot gas generated by the oxidizer preburner (OPB).
gas enters the turbine and flows across the shielded support struts, through the first- and second-stage nozzles and
blades, and is discharged into the hot-gas manifold (HGI_. The turbine rotors are mated through a curvic coupling
and are held together with a circle of bolts. The second-stage rotor is integral with the pump shaft. Turbine blade-
to-housing leakage is minimized by lands on the outer perimeter of the blade shrouds that run against seals in the
turbine housing.
All components of the turbine are cooled by gaseous hydrogen flowing over or through them. Coolant is supplied from
the OPB coolant jacket. After cooling the turbine components, the coolant is exhausted into the hot-gas flow stream.
Turbine-to-OPB sealing is accomplished by a pair of concentric bellows that load dual seals in the turbine inlet flange
to the OPB. Turbine component materials are primarily of nickel- and cobalt-base alloys. The diameter of the turbine
rotors with blades is approximately 11 inches.
OUTLET
ROTOR
FIRST-STAGE ROTOR
INLET
COOLANT INLET
_PPORT STRUTS
NOZZLE
SECOND-STAGE NOZZLE
1-20
LSS- EC-P-45A
_md^^^
RSS-8559-1-1-1
19. HIGH-PRESSURE FUEL TURBOPUMP
The high-pressure fuel turbopump (HPFTP) is a three-stage centrifugal pump that is-directly driven by a two-stags
hot-gas turbine. The pump receives fuel from the low-pressure fuel turbopump (LPFTP) and supplies it at increased
pressure, through the main fuel valve (MFV), to the thrust chamber assembly coolant circuits. The turbine is power-
ed by hot gas (hydrogen-rich steam) generated by the FPB.
Fuel flows in series through the three impellers from pump inlet to outlet, with flow being redirected between the
impellers by interstage diffusers.
Coolant flow across the pump-end bearings is pz'ovtded by the pumping action of a slinger located between the bearings
and first-stage impeller. The coolant is tapped off downstream of the pump inlet turning vanes and returned to the
inlet of the first-stage lmpeUer. Coolant flow to the turbine-end bearings is supplied from the pump balance piston
cavity through the shaft static lift-off seal
Axial rotor thrust is controlled by a self-compensating, double-acting balance piston that operates between high- and
low-pressure orifices to maintain thrust at zero during normal operation. A thrust bearing (not shown), located at
the pump inlet end of the rotating assembly, controls rotor thrust during start and cutoff transient operations.
Before engine start, leakage from the pump into the turbine ts prevented by a spring-leaded-closed/propeliant
pressure-actuated-open, llft-off seal. During engine start the seal nose is separated from its mate ring when
increasing fuel and turbine-gas pressure overcomes the spring force. A positive separation between the seal nose
and mate ring is maintained until engine shutdown when actuating pressure decreases below spring force. Propellant
flow through the seal and mate ring is used to cool the turbine-end bearings and the turbine components.
The HPFTP is flange attached to the hot-gas manifold (H(_I) and is canted out from the engine centerltne at a 10-degree
angle. The HPFTP is a line replaceable unit with an overall dimensional envelope of approximately 22 by 44 inches.
INSULATION
AND SHIELD
PUMP INLET
"_OUS1NG
X PUMP HOUSING
TO MAIN FUEL
VALVE
INTERSTAGE
DIFFUSERS
SLINGER
PUMP-END
BEARING
COOLANT
SUPPLY PORT
FROM LOW-PRESSURE
FUEL TURBOPUMP
BALANCE PISTON
INSULATION
AND SHIELD
LSS- EC-P-46A
1-21
_--.'4!000
RSS-8559-I-1-1
3. SSME PROPELLANT FLOW SCHEMATIC
The SSME uses a staged combustion cycle in which propellants are partiallyburned at high pressures and relatively
low temperature in the preburners and then completely burned at high pressure and temperature in the main combus-
tionchamber.
The propellant system uses four turbopumps. The two low-pressure turbopumps operate at low speed to permit low
pressures in the vehicle tanks. The function of these pumps is to provide enough pressure to eliminate cavitation at
the inlets of the high-speed, high-pressure pumps. The discharge from the low-pressure pumps is fed to the inlets
of the high-pressure turbopumps.
Approximately 75 percent of the flow from the KPOTP goes to the main combustion chamber, and approximately
10 percent is directed to the preburner pump that raises the pressure to the preburners operating level. Small
quantities are bled through the heat exchanger for oxidizer tank pressurization and pogo suppression and the balance
of the oxidizer drives the hydraulic turbine powering the LPOTP and is then rectrculated to the inlet of the high-
pressure pump.
Approximately 20 percent of the high-pressure fuelpump discharge flow is used to cool the main combustion chamber,
drive the low-pressure fuel-pump turbine, cool the hot-gas manifold and injector,and provide fuel lank pressurant.
The remaining fuel is firstused to cool the nozzle, then supply the preburners.
The hot-gas hydrogen-rich steam from the fuel and oxidizer preburners drives the high-pressure pump turbines, then
flows to the main injector where it is mixed with additional oxidizer and fuel and injected into the main combustion
chamber.
O
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Space Shuttle Main Engine: Part Number RS007001

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