Info

"Data courtesy of The Boeing Company, Rocketdyne Propulsion and Power, at flight power level of 104.5% of design thrust. 'Data courtesy of Mitsubishi Heavy Industries, Ltd.

'LPOTP, low-pressure oxidizer turbopump; HPFTP, high-pressure fuel turbopump. rfBoost impeller stage for oxygen flow to preburners or gas generator.

"Data courtesy of The Boeing Company, Rocketdyne Propulsion and Power, at flight power level of 104.5% of design thrust. 'Data courtesy of Mitsubishi Heavy Industries, Ltd.

'LPOTP, low-pressure oxidizer turbopump; HPFTP, high-pressure fuel turbopump. rfBoost impeller stage for oxygen flow to preburners or gas generator.

Hot gas inlet flange

Entry slots to turbine nozzles

Hydrostatic bearing

Internal passages for supplying propellant to bearings

Pump volute with changing cross section

Shrouded impeller bearing

Turbine gas discharge flange

Typical nozzle

Turbine blades Turbine disk Shaft seal

Angular ball bearing for axial loads

Inducer impeller

Pump diffuser vanes

Pump housing

Nut holding inducer to shaft

Pump suction flange

Gas inlet manifold and turbine housing

Pump discharge flange

FIGURE 10-1. Cut-away view of an experimental turbopump demonstrator with a single-stage liquid oxygen pump impeller, an inducer impeller, and a single-stage turbine (one row of blades) on the same shaft. (Courtesy of The Boeing Company, Rocketdyne Propulsion and Power.)

single-stage propellant pump (with an inducer impeller ahead of the main impeller) is driven by a single-stage axial-flow turbine. The hot combustion gases, which drive this turbine, are burned in a separate gas generator (or a precombustion chamber or preburner) at a mixture ratio that gives gases between 900 and 1200 K; this is sufficiently cool, so that the hot turbine hardware (blades, nozzles, manifolds, or disks) still have sufficient strength without needing forced cooling. The gases are expanded (accelerated) in an annular set of converging-diverging supersonic turbine nozzles, which are cast into the cast turbine inlet housing. The gases then enter a set of rotating blades, which are mounted on a rotating wheel or turbine disk. The blades remove the tangential energy of the gas flow. The exhaust gas velocity exiting from the blades is relatively low and its direction is essentially parallel to the shaft. The pump is driven by the turbine through an interconnecting solid shaft. The propellant enters the pump through an inducer, a special impeller where the pressure of the propellant is raised only slightly (perhaps 5 to 10% of the total pressure rise). This is just enough pressure so that there will be no cavitation as the flow enters the main pump impeller. Most of the kinetic energy given to the flow by the pump impeller is converted into hydrostatic pressure in the diffusers (the diffuser vanes are not clearly visible, since they are inclined) and/or volutes of the pump. The two hydrostatic bearings support the shaft radially. All bearings and shaft seals create heat as they run. They are cooled and lubricated by a small flow of propellant, which is supplied from the pump discharge through drilled passages. One bearing (near the pump) is very cold and the other is hot, since it is close to the hot turbine. The angular ball bearing accepts the axial net loads from the unbalanced hydrodynamic pressures around the shrouded impeller, the inducer, and also the turbine blades or the turbine disk.

A novel, high speed, compact, and light weight liquid hydrogen turbopump is shown in Fig. 10-2 and in Ref 10.2. It is intended to be used with a new upper stage hydrogen/oxygen rocket engine with a thrust of about 50,000 lbf (22.4 kN), a delivered engine specific impulse of 450.6 sec at an engine mixture ratio of 6.0. This engine will run on an expander cycle, with a chamber pressure of 1375 psia (96.7 kg/m2) and a maximum internal fuel pressure of 4500 psi (323.4 kg/m2) at the fuel pump discharge. The unique single-piece titanium rotor turns nominally at 166,700 rpm, has two machined sets of pump vanes, a machined inducer impeller, a set of machined radial inflow turbine

Housing for filtered bearing supply

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