Chamber Pressure

FIGURE 6-10. Simplified view of the RS-68 rocket engine with a gas generator cycle. For engine data see Table 10-3. (Courtesy of The Boeing Company, Rocketdyne Propulsion and Power.)

Oxidizer flow control valve

Oxygen pump

Liquid oxygen

Regeneratlvely cooled thrust chamber and nozzle

Liquid hydrogen

Oxidizer flow control valve

Oxygen pump

Liquid oxygen

Liquid hydrogen

Propellant shutoff valves

Regeneratlvely cooled thrust chamber and nozzle

Fuel pump

Fuel cooidown and pressure relief valve

FIGURE 6-11. Schematic flow diagram of the RL10B-2 upper stage rocket engine. For data see Table 8-1. (Courtesy of Pratt & Whitney, a division of United Technologies.)

Propellant shutoff valves

Fuel pump

Fuel cooidown and pressure relief valve

FIGURE 6-11. Schematic flow diagram of the RL10B-2 upper stage rocket engine. For data see Table 8-1. (Courtesy of Pratt & Whitney, a division of United Technologies.)

complex pumps, turbines, and piping. The turbine flow is relatively high and the turbine pressure drop is low, when compared to an open cycle. The staged combustion cycle gives the highest specific impulse, but it is more complex and heavy. In contrast, an open cycle can allow a relatively simple engine, lower pressures, and can have a lower production cost. A variation of the staged combustion cycle is used in the Space Shuttle main engine, as shown in Figs. 6-1 and 6-12. This engine actually uses two separate precom-bustion chambers, each mounted directly on a separate main turbopump. In addition, there are two more turbopumps for providing a boost pressure to the main pumps, but their turbines are not driven by combustion gases; instead, high-pressure liquid oxygen drives one booster pump and evaporated hydrogen drives the other. The injector of this reusable liquid propellant high-pressure engine is shown in Fig. 9-6 and performance data are given in Tables 10-1 and 10-3. While the space shuttle main engine (burning hydrogen with oxygen) has fuel-rich preburners, oxidizer-rich preburners are used in the RD120 engine (kerosene/oxygen) and other Russian rocket engines. See Table 10-5. Another example of a staged combustion cycle is the Russian engine RD253; all of the nitrogen tetroxide oxidizer and some of the unsymmetrical dimethyl hydrazine fuel are burned in the precombustor, and the remaining fuel is injected directly into the main combustion chamber, as shown in Table 10-5.

Hydrogen f fuel inlet 1

Low pressure fuel (booster)

Oxygen inlet

Hydrogen f fuel inlet 1

Low pressure fuel (booster)

Oxygen inlet

Preburner and high pressure oxygen ^ turbopump

Preburner and Fuel turbopump with 3-stage Hydrogen pump

Part of oxygen flow is pressurized to a higher pressure with a separate impeller

Coolant control valve

Regeneratively cooled tubular nozzle

Thrust chamber gas exhaust

FIGURE 6-12. Flow diagram for the staged combustion cycle of the Space Shuttle Main Engine (SSME) using liquid oxygen and a liquid hydrogen fuel. (Courtesy of The Boeing Company, Rocketdyne Propulsion and Power.)

Preburner and high pressure oxygen ^ turbopump

Preburner and Fuel turbopump with 3-stage Hydrogen pump

Part of oxygen flow is pressurized to a higher pressure with a separate impeller

Coolant control valve

Regeneratively cooled tubular nozzle

Thrust chamber gas exhaust

FIGURE 6-12. Flow diagram for the staged combustion cycle of the Space Shuttle Main Engine (SSME) using liquid oxygen and a liquid hydrogen fuel. (Courtesy of The Boeing Company, Rocketdyne Propulsion and Power.)

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Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

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