Adopting RNG k-E Essay

Length: 787 words

The genealogy can effectively simplify the thrust chamber structure, reduce costs and increase system reliability. It is especially promising in the tiny thrust engine. Compared with hydrogen, methane has better stability characteristics and higher density specific impulse. It can be used in a variety of space missions and planetary vehicles. In this paper, a preliminary design of NON gas oxygen / methane vortex cooling thrust chamber is performed.

The Influence of the fuel Injection methods and the configurations of the thrust chamber on improving heat distribution of head- panel are mainly investigated. Turbulence model and PDF non- premixed combustion model, Fluent 6. 3 commercial software was used to simulate the flow field of thrust chamber for sphere-head thrust chamber, cylindrical thrust chamber, variety of fuel injection methods (axial, impinging and tangential) and their combinations.

Unlike traditional thrust chamber, injection of vortex cooling thrust chamber is usually arranged at both ends of the thrust chamber, as shown in figure 1. Gas oxygen is tangentially injected at the end of the thrust chamber, and forms a vortex flow field of inner and outer vortex layer, which are coaxial and reverse. Due to this special structure of flow field, the propellant flow mixing

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and combustion is limited in the core inner vortex, while outer vortex reverts the contact of high temperature gas with the “all surface, and then reduce the surface heat load caused by chemical combustion and heat convection.

At the same time, high-speed rotating vortex effectively improved the side wall temperature rise. Rhea technology was first proposed by the Orbital Technology Corporation. It focused on test research and technology validations-3 of a hydrogen / oxygen vortex cooling thrust chamber, and obtained rich test data. The main factors affecting the thrust chamber specific IAC-13- CA, P, 25. Pixie 64th International Astronautically Congress, Beijing, China. Copyright 02013 by the impulse performance and the key structure of heat load were analyses and summarized.

Research showed that, the vortex injection techniques could eliminate cooling structure, so as to effectively simplify thrust chamber structure design, reduce development cost, increase chamber life and improve safety and reliability. The characteristics of the side wall of low temperature, has great potential applications-5 in the upper stage small thrust engine. And the engine has the characteristics of fast ignition, steady-state operation under low temperature, high performance etc.

Fig. L Vortex cooling thrust chamber structure and flow schematic In China, Jeanine IL and others of Beijing University of Aeronautics and Astronautics focused on different thrust level test and combustion visualization. Their results confirmed research of Martial, 3, 4 et al. Experimental results showed that, good cooling effect of thrust chamber side wall was obtained, but ablation existed near the head and fuel injection panel, and specific impulse efficiency needs to be improved.

The conclusion was also proved in the simulation of the flow field characteristics of the thrust chamber, as hon. in figure 2. Fig. 2 Simulation results of the characteristics of thrust chamber flow field The simulation shows the existence of a low velocity recirculation zone in the thrust chamber head, where the high temperature gas cannot be took away, resulting in high temperature head panel. At the same time, ineffective mixing of part of the axially injected fuel leads to loss of specific impulse thrust.

Taking into account many excellent features of methane when adopted in upper stage small thrust engine applications, this paper adopts gas oxygen / methane propellant combination. After standard design f the thrust chamber, thrust chamber performance special thrust chamber configuration, thrust chamber structure parameters and gas oxygen flow parameters Nerve conducted. Changing rule of vortex cooling thrust chamber performance with parameters, and influence of thrust chamber parameters on the thermal load of key structure (head, side wall) are studied to provide basis for the design of engine.

II. METHOD OF APPROACH 11. 1 Work Conditions Rhea combustion chamber pressure was Pc=l Amp, mixing ratio was O/F=2. 757, and ground thrust was NON. Referring to the previous design experienced of est. structure components of hydrogen/oxygen vortex cooling thrust chamber, two kinds of thrust chamber of plane and spherical head were designed, as shown in figure 3. Fig. 3 Schematic profile two kinds of thrust chamber design or ensure same thrust chamber volumes, the thrust chamber of spherical head is slightly longer than the cylindrical thrust chamber.

The nozzle throat size and Page 2 of 9 shape of the two chambers keep invariant in order to offset the estimation error of thrust chamber performance caused by nozzle efficiency changes. 4 groups of numerical calculation were carried out especially, including research on the influence of fuel Injection effect (A), special head (B), structure parameters (C) and oxygen gas flow parameters (D) on thrust chamber performance and heat load of key structures. The detailed calculation conditions are shown in table 1-4.

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