Experimental and Simulated Straightening of Metal Halide Arcs Using Power Modulation

Years of research in the fundamentals of acoustically generated flows in HID arc tubes for enhancement have recently produced record breaking performance in converting wall plug power to useful white light. In this paper simulated results show how power modulation produces straightened arcs. A fully unsteady compressible 2D flow model is used to reproduce observed instantaneous pressure and temperature oscillations and the results are time averaged and rendered to visualize the bulk gas flows. Sound-wave propagation and induced flows result from full coupling between the oscillating current, the energy balance, the ideal-gas law and conservation of mass and momentum, on two separate time scales. Experimental verifications of the instantaneous and the time averaged effects are included.