Numerical Simulation Of Combustion Flow Field In Engine Ignition

Gas turbin has the advantages of efficient, small volume, lightness, simpleness of maintenance, good flexibility, high reliability of operation, high degree of automatization and low cost. At present it is widely used in aviation, power station, natural gas transportation, petroleum, railway and shipbuilding industry. Combustor is an important component in the gas turbine. During the startup, it is important to ignite the combustor reliably.Plasma ignition for engine is a new pattern of portfire, it firstly lights up the start-up oil and forms ignition torch to ignite the main oil in the combustor. It is a new technology, at present only Ukraine has used this technique in marine gas turbine and the ground gas turbine to increase the reliability of retrofires and extend the concentration limit of retrofires. There are much complicated and exquisite physical and chemical processes when the oil and the air are mixed. For some theories of the combustion are not mature and the partial differential equations are so complicated, it is very difficult to get the accurate flow field distribution. So it limits the combustion theory to design combustion equipment.With the rapid development of computational fluid dynamics and combustion theory, applying the computer to numerically simulate the complicated processes in the plasma ignition is possible. Using numerical simulation can estimate the parameters, which are not easy to measure from experiments, can improve reliability and reduce the cost. So numerical simulation is a new pattern way to study the inner mechanism of the plasma ignition.In this article, constituting some equations which reflect the flow law and building and applying many mathematical models of physical and chemical reactions in the plasma ignition: applying RNGk-ε two equations turbulence model to calculate the turbulence parameters; applying simplified reaction system model and applying diffusion combustion model and Discrete Transfer Radiation Model. During the numerical simulation, applying the curvilinear coordinates for the pomplex geometry of the computational field; applying the mixing format to discretize the equations; applying SIMPLEC algorithm method to achievepressure-velocity coupling and applying the multigrid scheme to obtain converged solution.Using above models and methods, we obtain turbulent reacting flow field distribution of parameters; including temperature, pressure, turbulent kinetic energy and its dissipation rate, turbulent viscosity, velocity, density and mixture fraction of products. Results are compared by using different boundary conditions. These results are significant to design and improve the plasma ignition.