Adaptive grid computation of three‐dimensional natural convection in horizontal high‐pressure mercury lamps

Abstract

AbstractA three‐dimensional model has been developed to compute the thermofluid transport within a discharge arctube. The model has proved very useful for guiding the choice of design parameters to optimize the lamp performance. However, uncertainties exist with respect to quantitative aspects of the physical model, especially those related to radiation heat transfer. In the present work a grid refinement procedure and an adaptive grid method are used to improve the quantitative accuracy of the model and to help improve the physical modelling. The adaptive grid method, based on the multiple one‐dimensional equidistribution concept, can responsively redistribute the grids to optimize the grid resolutions. Adaptive grid solutions modify the predicted maximum gas temperature, the buoyancy‐induced convection strength, the location of the high‐temperature core, and the wall temperature profiles. The adaptive grid solutions show more consistent trends when compared to the measurements. On the basis of the quantitatively more definite information, adjustments can be made with regard to the uncertainties of the physical model.