Numerical analysis of the two-frequency technique for measuring the torch discharge resistance with or without taking into account its equivalent inductance
A. O. Puzanov · RADIOFIZIKA I ELEKTRONIKA · 2018
The torch discharge (TD) is applied in a number of areas of science and technology. However, the lag in theoretical research from ever-growing urgent needs makes the solution of many practical-oriented problems related to the TD relevant. In the present paper, the study of the proposed by the author original method for measuring the resistance of the TD (Rd) taking into account the TD inductance L is continued. The presented numerical calculations are supplemented by the previously performed estimations of the theory application area. The sought resistance Rd is considered as frequency independent within the theory. Performed estimations and calculations confirm the applicability of the approach presented both with and without taking into account the TD inductance in the frequency range from 1·10 ‑3 to 3.0 GHz. It is shown that a necessity to account the inductance of the torch discharge of the power below 1 kW and the choice of appropriate frequency pairs f0,1 have to be studied in each case separately. A possibility to excite the torch discharge at two sufficiently different frequencies is mandatory. Numerical calculations of Rd without taking the inductance into account show that calculations accuracy depend weakly on the height of the torch discharge location relative to the ground. The accuracy increases if the discharge diameter decreases; the discharge length increases; the value of Rd is small and less than 1 kОhm; f0,1 frequencies converge. It results in a necessity to add an equivalent inductance into the Neiman’s scheme making appropriate modifications of the calculation formulae. It is shown that the resonant frequency fr is approximately proportional to fmax, which is the upper limit of the frequency range where the circuit theory remains applicable for the discharge modeling. Thus, the knowledge of fr and fmax allows one to refine the values of the function a, which is the ratio of voltages at which the electrical and geometrical characteristics of the torch discharge remain unchanged. The approach proposed results in more effective using of industrial resources.