Arc Diameter Estimation of a Rotating Gliding Arc Using a Simple High-Speed Camera and ``Gaussian Fit'' Function

This work reports the estimation of discharge diameter ( $d_{d}$ ) using ``Gaussian fit'' method applied on the discharge's image captured using high-speed camera (HSC). Work was conducted in a rotating gliding arc (RGA) and obtained the $d_{d}$ near the shortest (delta) and longest (Delta) gap between the electrodes, operated under 5 SLPM (transitional) and 50 SLPM (turbulent) flow rates of argon gas at atmospheric conditions. Gaussian fit was verified to be suitable to estimate the thickness of the objects that could be well differentiated from the background in the captured image. Furthermore, the results indicated that the gas flow rate is highly influential on $d_{d}$ . The average $d_{d}$ was thinned by approximate to 28%, from 0.29 to 0.21 mm, when the flow rate was increased from 5 to 50 SLPM, indicating the influence of turbulent eddies at 50 SLPM. The $d_{d}$ was varying along the discharge length under turbulent flow due to discharge's inhomogeneity in intensity arising due to twisting, curling, and knot formations. This work marks an essential step toward the characterization of the RGA reactor.