Simulation BREAKDOWN OF GAS MIXTURE ON COMSOL MULTIPHYSICS/ANSYS

There are two concentric aluminum pipes arranged in parallel. The inner pipe is solid and outer pipe is hollow inside. radius of inner pipe is 6cm and outer pipes is 18 cm. Inner pipe carries high voltage electricity (DC=100KV) and outer pipe is grounded. There is a space between inner and outer pipe which is 12cm. The space between the 2 pipe contains mixture of two gases 70% and 30% (Any gas mixture) respectively and having a pressure of 200KPa to 500KPa. Then we put wire particle inside ( 10mm length and 0.25mm radius ) the space between 2 pipes as we increase the dc voltage, the wire particle start floating and breakdown occur. I want to get 2 user defined functions (Concentration of gas mixture and Pressure) and mathematical formula or derivation to get output as follow: get the breakdown voltage? lifting voltage when the wire particle lift? How much energy is absorbed by the particle to start floating? Feel free to ask any question. If you need i will give you a document for help.