Effect of flow rate and arc length changes on velocity and temperature field of TIG arc

A steady two-dimensional (2D) axisymmetric model was developed in order to investigate the temperature and flow fields in a free burning TIG arc.A series of arc models were founded.The different flow and temperature fields of the arc in different flow rates and different arc lengths were calculated and compared.With the increase of arc length,the temperature of arc,the arc voltage and the flow velocity are increased.But the velocity stabilized in a certain value when the arc length is 8-10 mm.The moderate arc length can assure the arc with optimal heat input and better protection.The increased flow rate of shiel-ding gas compresses the arc and causes the energy emission to be much closer to the axis center,and the highest temperature is al-so increased.With the flow rate further increases,the energy e-mission and heat transfer increase,the highest temperature de-clines.The anticlockwise swirl streamtraces become larger as the flow rate increases and govern the arc region,thus the quality of flow protection is improved.The area of higher velocity in the arc column has left the original position and moved to the electrode.But the higher flow rate will delay the radial velocities on the an-ode.