Experimental investigation of thermal boundary layer thickness effects on corona discharge current with razor-isothermal cylinder geometry

In the present work, the corona discharge was established with heated horizontal isothermal cylinder electrode as a ground electrode and axial razor placed below the cylinder as a high voltage electrode in atmospheric pressure air. Thermal boundary layer visualized using 100 mm optical plate Mach-Zehnder interferometer. The test was started from near the onset corona voltage applied to the razor and fixed cylinder temperature surface. Below the onset corona discharge, the interferograms shows a slight effect on thermal boundary layer. Applying the onset corona voltage resulted in abrupt influence of thermal fringes at the onset corona voltage (12 kV) which was accompanying with an acoustic noise. High voltage was connected to a razor that was located 42.5 mm below and parallel with the axis of a heated horizontal cylinder. In the various corona voltages started from onset corona voltage to prebreakdown threshold, the thickness of thermal boundary layer and corona current were measured. The corona current started to increase at higher thickness of thermal boundary layer.