Physics-Based Circuit Model for a Water-Wall High-Temperature Arc Lamp Using Finite Volume Method
High-temperature arc lamps are used for thermal processing of semiconductor wafers. A vortex water wall on the inner surface of the lamp's enclosure is used to provide cooling for the glass. It has been experimentally observed that, above certain levels of injected energy, the arc shows an unstable behavior and is self-extinguished. In this paper, a physics-based model for the water-wall high-temperature arc lamp is derived and implemented in the form of an equivalent electrical circuit. The equivalent circuit is then coupled to the flash power supply equivalent circuit to validate the derived model against experimental voltage and current waveforms.
Modelling and simulation of radiative energy transfer in high-voltage circuit breakers
In high-voltage circuit breakers (HVCBs) a high current phase description is essential to accurately estimate the pressure increase in the heating volume. In this paper a HVCB model is proposed including turbulence and radiation models. The main focus was set on two major aspects: the radiation models used generally in computational fluid dynamics studies and the calculation time. For the radiation, due to the limitation of the P1 model and to the consuming calculation time of the DO model, an original hybrid approach (the P1 approximation mixed with a discrete ordinate method) is presented. The results of the different models are presented and discussed. Using the hybrid model, the pressure increase is compared with experimental results validating the model. The calculation times of the different methods are compared.
Calculations of radiation transfer in SF6 plasmas using the method of partial characteristics
Radiation emission and absorption in SF6 arc plasmas are important energy transfer processes. Exact calculations, though possible in principle, are usually impossible in practice because of the need to treat about 400 spectral lines and also continuum radiation spanning wavelengths from 10 nm to 10 mu m. From calculated spectral absorptivities at 300000 radiation frequency points for SF6 plasmas of 1, 5 and 10 bar from 300 K to 35000 K, we have calculated two integrals over radiation frequency. These integrals, designated Som and Delta Sim are used in the approximate method of 'partial characteristics', as formulated by Sevast'yanenko. The validity of this method of partial characteristics has been demonstrated by comparing exact calculations with the approximate calculations to evaluate radiation intensities, radiation fluxes and divergence of radiation fluxes for specified temperature profiles. Agreement to within 20% is obtained with exact calculations, but with a reduction of computation time of about four orders of magnitude. Furthermore, the new method has been used to evaluate net emission of radiation as a function of position in an algorithm to predict temperature profiles of wall stabilized arcs of any given current. Fair agreement is obtained between predicted and experimental values of central are temperatures and electric field strengths as a function of current for SF6 arcs of radius 0.25 cm at a pressure of 1 bar.