Two diff heat source in welding is possible in actual practice only. The same experience can not be simulated as it is actually happening in Ansys to the best of my knowledge. However, you just need Goldak's double ellipsoidal moving heat source equation. In that equation, there are some scalar parameters which you can get from your pilot experiments. Additionally, you have to use an exact coordinate system every time step to apply your heat input. You can calculate your heat input using Q1 = weld eff1 X Volt1 X Curr1 for 1st heat source and Q2 = Weld eff2 X Volt2 X Curr2 and finally total heat input will be Q = Q1 + Q2. You can refer to Goldak's formula on the internet and will see how you can input a, b, cf, cf, cr, ff, fr in the equation. Write code on APDL or command file of Ansys WB. Refer these link for the code to apply Goldak's equation: