Field-enhanced Microwave Plasma Thruster Flow Field Numerical Study

Microwave plasma thruster (MPT) is a space propulsion system that uses microwave to heat low molecular weight propellant gas to a high temperature. As other conventional rocket engines, the propellant gas then expands isentropically through the nozzle to produce thrust. The microwave-sustained plasma can be created without thruster erosion and maintained away from the material surface of the thruster. Hence MPT has prospective application in spacecraft task.In order to improve the performance of MPT, some theoretical analysis and numerical simulations are carried out. The main workof this thesis is listed below:?The interaction between flow field, electromagnetic field and plasma is researched. The result has given the mechanism how plasma absorbs microwave energy by applying a strong magnetic field.(2) On the assumption that the fluid is two-dimensional axial symmetry flow; a numerical simulation of the flow fluid in the resonant cavity is presented by using Semi-Implicit Method for pressure-Linked Equations Revised.?The numerical simulation of electromagnetic field in the resonant cavity is presented by using Finite-Difference Time-Domain Method(FDTD).?The composition of argon plasma is computed by using Shaha Equations.?Plasma Governing equations include Navier Stokes Equations, Maxwell Equations and Shaha Equation. Semi-Implicit Method for Pressure-Linked Equations Revised is used to solve N-S equations, in this numerical model, electromagnetic fields and applied magnetic field are added into Navier-Stokes equations as sources. FDTD is used to solve Maxwell Equations.By solving N-S equations with SIMPLER, Maxwell Equations with FDTD and Shaha equations with Finite Difference Method, the coupling flow field, temperature field, electromagnetic fields and plasma composition are simulated numerically.From the theoretical analysis and numerical simulation, such conclusions can be drawn:?If the air pressure in the resonant cavity is so low that the air pressure can be neglected, The plasma is cold plasma. Cold plasma can absorb the microwave energy greatly under the applied magnetic field. When the air pressure in the resonant cavity is as high as 2 atm, the applied magnetic field can be neglected.? electrical conductivity is the most important factor that affects numerical simulation results. Even very trivial vibration can cause great difference to the results of flow fields, electromagnetic fields and plasma parameters distribution.(3)The electromagnetic field can affect the temperature greatly by joule heating, and thus affect the plasma parameter distribution. The results also show that when the air pressure as high as 2 atm, the Lorentz force can be neglected in the N-S Equations of plasma.? When the air pressure in the resonant is 2atm,the applied magnetic field is 0T,0.5T, IT, 2T repectively the peak temperature in the flow field is. 4598.56K, 5585. 84K, 5636. 24K, 5718. 24K accordingly.By design a more proper magnetic field, the value of temperature may be up to a higher value.