Peng Han, Xiaofu Ye and Xi Chen*

Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
cx-dem@mail.tsinghua.edu.cn

A transient method is employed to measure the local heat flux distribution along the surface of a flat plate normal to an impinging plasma jet. A small copper cylinder with 1 mm diameter and 1 mm length carrying with a thermocouple was used as the sensitive element of the plate-type heat flux probe. The frontal surface of the small cylinder is flush with that of the plate and is insulated from the plate by ZrO2 powders. When the plate-type heat flux probe is swept across the plasma jet, the local heat flux distribution for heat transfer from the plasma jet and the plate probe normal to it can be determined from the temperature response of the small cylinder. The inverse Fourier transformation has been employed to eliminate undesired noise signals and obtain smooth signal curves. Different gas flowrates from 0.3 to 2.2 STP m3/hr (both laminar and turbulent regimes are covered), arc currents and the distances between the exit of the plasma-jet generator and the normal plate are used. The experimental heat fluxes can be well approximated by the Gaussian distribution. The modelling domain includes the arc plasma generator, the plasma jet and the flat plate. The upstream boundary conditions of the plasma jet are obtained from the output of the modelling of the plasma generator. Both the laminar and turbulent regimes and the mixing between the ambient air and the argon plasma jet are all included in the modelling. The heat fluxes on the plate surface are also shown to be well presented by the Gaussian distribution.