Numerical Simulation And Experimental Verification Of Steady-state Process Oriented To PLASMA-FIX51 Micro-beamed Plasma Arc

Micro-beamed plasma arc has good characteristics such as large heat density,good stability,straight outline and tiny affection region.It can be applied in the precise welding of extremely thin plates.Due to its features,there will be a bright future to apply this technology in surface treatments such as surface polishing and surface micro-melted.But the working process occurs with complex physical phenomena and it's also affected by many influences.It is difficult to measure the physical distributions and the influences by experiments directly.As a fact that computer science develops rapidly,it is realistic to solve this problem by numerical simulation.This article combines the realistic welding torch PLASMA-FIX51 with experimental parameters to research on the essence of influences of micro-beamed plasma arc.Firstly,based on the theory of hydromagnetics,a two-dimensional model of microbeamed plasma arc was developed with the commercial simulation software COMSOL.The numerical model is the same size as the plasma torch in real practice.After making proper definitions of boundary conditions,researches on the temperature field,flow field and electromagnetic field were developed under DC currents.The results revealed the essences and effects of mechanic compression,heat compression and electromagnetic compression.Secondly,simulations on the experimental parameters and plasma torch structure were done to reveal their influences to the physical field distributions.Influences as input current,plasma gas inlet flux,protecting gas inlet flux,distance between nozzle outlet and anode,size of nozzle output and shape of cathode were also developed in this thesis.At last,the model was verified by spectrum method.Spectrum at the specific point of the micro-beamed plasma arc was collected using the needle-scanning method with the scanning collection system.Afterwards,the spectrum was marked using the data from NIST.Based on Boltzmann plot method,spectrum information was transferred into arc temperature.After comparing the temperature from simulation with that of the experiment,it was found they matched well within 17% error range.STARK broadening method was used to measure the electron density for further study.