ANALYSIS OF RADIAL ENERGY LOSS IN AN ARC HEATER CHANNEL

摘要

The paper deals with an experimental modular-type arc heater with the blasted electrical arc burning in argon. Its typical operating parameters are current up to 220 amperes, voltage about 100 volts, and argon flow rate up to 22 grams per second. Numerous experiments were carried out and many sets of integral quantities were measured. The measured data, including the arc current I, the arc voltage U, the flow rate of the working gas G, and the energy loss of the arc heater channel P_(z), served as the input data of a mathematical-physical model describing phenomena inside the arc heater channel. The model is based on the mass and energy conservation equations and Ohm law and uses the known material properties of the working gas. The model makes it possible to study energy flows both in axial and radial directions. In this paper, attention is focused on radial energy transport in the anode channel. The analysis of measured and computed data has proved radiation to be the main mechanism of radial energy transfer from the arc to the channel wall. Using the computed radial dependence of the temperature T(r) in the arc heater channel cross-section, and the energy loss P_(z) and the electrical intensity E along the arc heater axis together with the temperature dependency of argon electrical conductivity sigma(T), the specific radiation coefficient W_(e) of the working gas can be approximately estimated in the limited temperature range. The obtained temperature dependency of the specific radiation coefficient of argon is given in figures and compared with theoretically computed data [1].