Supersonic Combustion Numerical Study On Shear Flow

Combustion with releasing heat effectively in supersonic flow is one of the most important, as well as the most difficult, technologies in researching and developing supersonic combustion ramjet. To analysis combustor structure's contribution to fluxion and combustion explicitly, it is necessary to study the impaction of wave system and fire temperature on chemical reaction and heat release's procedure. Code has been developed for simulating supersonic combustion of HC fuel occurring in supersonic combustion propulsion systems.Two-dimension high precision cold-state model with the ability to capture shock wave is established. NND difference scheme divergences convection item and Runge-Kutta scheme iterates time item. The calculated outcome agrees well with the experiment data and analytic solution. The impaction of numerical precision on the accuracy of simulated flow field is checked. Curving level of throat wall arc mesh is compared to see the effect on flow loss. And above work indicates the code reliable. To analyze particularly the shear flow and chemical reaction procedure occurred in supersonic turbulent combustion field, supersonic combustion mechanism is surveyed on by reading papers thoroughly. And the reduced chemical reaction mechanism of supersonic HC propellant is confirmed. As the production of splitting reaction, ethane is plentiful in the hydrocarbon. The algebraic B-L eddy model, Prandtl mixing length model as well as Arrhenius finite speed rate chemical reaction combustion model is introduced to above cold-state model.By simulated supersonic combustion in'double-chamber', wall-pressure value is compared with experimented data. the simulated values accord well with experimented data. Two different work condition of combustion in chamber is contrasted to see the effect of flowing state on combustion and it concluded that: First, shear flowing enhances air and gas's diffusion and mixing. Great difference in pressure for two flow made pressure wave system and it help to extend the delay time for gas in chamber, which increases combustion effusion.Second, to increase combustion effusion, the inlet temperature of air and gas should be enhanced in the range of heat releasing in chemical reaction.Third, the first work condition is unburned absolutely and the second work condition is burnt in shear layer of inlet and the end of down wall zone in straight segment.Last, to optimize chamber's construction, installing gas nozzle along the axis of chamber is a measure. That can expand gas and air's interaction area and the spa cement of gas into airflow.Wave systems are analyzed from predicted flow parameters. Combustion state is evaluated from the distribution of chemical component density. Therefore, theoretical explanation is afforded to improve and optimize chamber frame.