Numerical Investigation of Symmetry Breaking and Critical Behavior of the Acoustic Streaming Field in High-Intensity Discharge Lamps

TL;DR

This paper presents a 3D multiphysics model to study acoustic streaming in high-intensity discharge lamps, revealing a phase transition to asymmetry at a critical force, akin to ferromagnetic behavior, and its relation to light flicker.

Contribution

It introduces a computationally efficient model capturing symmetry breaking and critical behavior of acoustic streaming in discharge lamps.

Findings

Velocity field undergoes a phase transition to asymmetry at a critical force.

System exhibits behavior similar to ferromagnet near the Curie point.

Model provides insights into light flicker phenomena.

Abstract

For energy efficiency and material cost reduction it is preferred to drive high-intensity discharge lamps at frequencies of approximately 300 kHz. However, operating lamps at these high frequencies bears the risk of stimulating acoustic resonances inside the arc tube, which can result in low frequency light flicker and even lamp destruction. The acoustic streaming effect has been identified as the link between high frequency resonances and low frequency flicker. A highly coupled 3D multiphysics model has been set up to calculate the acoustic streaming velocity field inside the arc tube of high-intensity discharge lamps. It has been found that the velocity field suffers a phase transition to an asymmetrical state at a critical acoustic streaming force. The system behaves similar to a ferromagnet near the Curie point. Furthermore, it is discussed how the model allows to investigate the light flicker phenomenon. Concerning computer resources the procedure is considerably less demanding than a direct approach with a transient model.