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Rocket Engines
Published in Ahmed F. El-Sayed, Aircraft Propulsion and Gas Turbine Engines, 2017
Important data on the RD-170/171 Turbopump arePropellants: LOX/keroseneMass flow rate: ~2.4 tons/sPressure of thrust chamber: ~250 barTurbine power: ~200 MWRotational speed:~14,000 rpmPressure of gases driving the turbine: ~500°CFigure 19.10 illustrates three kinds of turbopump systems used for pump-fed liquid-propellant rockets. Figure 19.10a shows a gas generator cycle. A part of the fuel and oxidizer is burnt in a separate combustion chamber identified as pre-burner. The products of combustion of this small chamber are used to drive the turbine before exhausted to ambient pressure. For this reason, it is identified as open cycle [3]. The gas turbine has a high-pressure ratio. To minimize weight, a small number of stages are employed; thus, a moderate turbine efficiency is attained. Combustion pressure is also moderate on the order of 5.0 MPa. Examples are the Japanese LE-5 engine, which was used in the second stage of the H-1 rocket, the Vulcain 2 engine (European first-stage rocket engines for the Ariane 5), and many U.S. engines, including the Rocketdyne J-2 and the F-1 engines.
Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
One of the first choices to be made by the engine designer is the value of combustion chamber pressure. This choice is also the result of a series of trades. For this exercise, 2,000 psia has been chosen and is a good first approximation for the optimum value when recurring costs are one of the more important parameters. This value will provide good performance, while simplifying turbomachinery to two pump stages with moderate turbine temperatures. An initial assumption needs to be made as to engine cycle. For a booster application, either a gas generator cycle or a staged combustion cycle usually provides
Influence of Doped H2O or H2 on Soot Production and Power Capability in the Fuel-rich Gas Generator
Published in Combustion Science and Technology, 2022
Yujun Li, Taichang Zhang, Tao Yuan, Xuejun Fan
In recent years, reusable rocket is a hot spot and a trend of space development at home and abroad, which can greatly reduce the cost of space launch (Donahue et al. 2008). The rocket engine system is the core of the rocket, and the gas generator cycle is one of the main cycle modes of the rocket engine. At present, the most popular reusable Falcon 9 rocket uses the Merlin series engine which employs the rich-fuel gas generator (Vozoff and Couluris 2008). For the LOX/kerosene rocket engine with gas generator cycle, the high concentration of soot and the large area of coke deposition in the pipeline (Edwards 2006) have adverse effects on the rocket engine system and structure, thus reducing the performance and operation life of the rocket engine. It is not conducive to the reuse of the rocket. Therefore, it is necessary to study influential factors on the formation mechanism as well as the amount of soot and coke deposition during the combustion of aviation kerosene. The relevant studies have been performed. In soot formation mechanism, Hai Wang (Wang 2011) reviewed the research status of sooting processes in the past 20 years, including soot precursor formation, particle nucleation, and mass/size growth. Formation mechanism of coke deposition, including the chemical processes of coke deposition formation and the factors affecting deposition content has been extensively studied (Beaver et al. 2005; Heneghan and Zabarnick 1994; Spadaccini, Sobel, Huang 2001). In the gas generator carbon deposition, the effects of mixture ratios and combustion pressure on soot formation and deposition characteristics were studied in a fuel-rich LOX/kerosene gas generator and a GOX/kerosene gas generator (Feng et al. 2017; Lausten, Rousar, Buccella 1985; Lawver 1983). The carbon deposition and soot formation characteristics of RP-3 kerosene under certain conditions were studied (Abdalla et al. 2020; Pei and Hou 2016), which indicates different types of kerosene also affect carbon deposition and the formation of soot. In addition, the development of numerical calculation also enables researchers to further study the characteristics of coke and soot (Foelsche et al. 1994; Yu and Lee 2007). For some hydrocarbon fuels, such as gasoline, the effects of the addition of alcohol and ether on the soot formation and combustion properties of the fuel were studied (Liu et al. 2018; Zhu et al. 2020), but as far as we know the additional components were rarely involved to suppress sooting in aviation kerosene and oxygen combustion. Moreover, influence of the additive on the power capability of combustion products of the gas generator were rarely studied.