Numerical Simulation And Structural Design Of Continuous Plasma Generator

The combustion chamber is one of gas turbine's core parts. The combustion efficiency is high and stably ignition property is the essential condition that the Taiwan gas turbine working high efficiently and reliably. Uses air plasma ignition technology in the engine accelerating the fuel burning process of physical and chemistry, expanding the ignition concentration limit, increasing the velocity of flame propagation, and enhancing the ignition reliability and the combustion stability to a great extent, avoiding the conflagration of combustion chamber and the phenomenon of caches fire caused by starting coldly many times, the pulverization of fuel badly, which has great significance for long-term development of gas turbine.This article designs one kind of plasma generator, and carries on numerical simulation to it. In the process of numerical simulation, establishing the geometric model of plasma generator, and meshing it, setting solution domains and boundary conditions. Establishing mathematical model of the arc based on principle of conservation of mass, momentum and energy conservation equation and Maxwell equations. Using COMSOL, the finite element analysis software to numerical simulation plasma electric arc's electric field, magnetic field, temperature field as well as flow field. Mainly obtained the plasma electric arc's velocity field, the temperature field distributed situation.Through the change of plasma generator's design parameter to study the influence to electric arc. Obtain the curve of plasma electric arc's temperature field and velocity field by coupling calculation. Specially obtain the maximum temperature curve of the negative pole wall's surface and the anode wall's surface. It provides certain reference to how to reduce the electrode ablation, in order to design the plasma igniter structure more reasonable and provide certain theory instructionAs is the computed result indicated, air inlet total pressure, angle of compression, nozzle length, nozzle radius and axial gap all have remarkable influence on the temperature and velocity field of plasma arc ignition. Through lowering the air inlet total pressure, reducing the compression angle of air, increasing the nozzle length, cutting down the nozzle radius and the axial gap of electrode, the arc ignition energy can be improved. Especially, through reducing the compression angle, increasing the nozzle length and cutting down the axial gap of electrode, it is going to have less influence on the velocity of arc and can improve the ignition energy. This can guarantee that the electric arc which has certain rigidity to issue the request ignition temperature, improved gas turbine's ignition performance, lengthened the plasma igniter's service life.