Two-dimensional streaming flows in high-intensity discharge lamps

Abstract

High-intensity discharge (HID) lamps embody a practical application in which acoustically generated streaming flows are used to significantly improve energy efficiency. Streaming in these lamps is examined using finite-element simulations in conjunction with available experimental results on the basis of the assumption that the streaming motion is excited by two-dimensional acoustic standing waves. Neither the magnitude nor the direction of the time-averaged flows is adequately explained by existing theory. Consequently, a modified streaming analysis is proposed in which the fluctuating flow is driven by an oscillating pressure field rather by a moving boundary and convective terms in both the instantaneous and streaming flows are included. Density variations are also shown to be important to the generation of the observed and simulated streaming. This analysis highlights the differences between streaming flows in HID lamps and those described in canonical problems appearing elsewhere in the literature.

Strong wave–mean-flow coupling in baroclinic acoustic streaming

“…These various distinguishing properties accord with prior experiments and numerical simulations; e.g. see Loh et al (2002); Hyun et al (2005); Lin & Farouk (2008); Nabavi et al (2008); Atkas & Ozgumus (2010); Dreeben & Chini (2011).…”

“…These changes are evident in the early experiments of Fand & Kaye (1960) and in subsequent experiments and numerical simulations; see e.g. Loh et al (2002), Hyun et al (2005), Lin & Farouk (2008), Nabavi et al (2008), Atkas & Ozgumus (2010), Dreeben & Chini (2011) and Karlsen et al (2018). Consequently, the resulting flow and associated transport cannot be computed simply by coupling the corresponding isothermal (e.g.…”

“…a fluctuating gravitational field in an otherwise gravity-free environment. Motivated by the observation that streaming velocities in high-intensity discharge lamps are two orders of magnitude larger than those predicted by Rayleigh streaming theory (Dreeben & Chini 2011), Chini et al (2014) derived a theory capable of accounting for both the observed streaming pattern and magnitude. As discussed more fully in § 2, the mechanism underlying this large-amplitude streaming is the baroclinic production of sound-wave vorticity arising from the misalignment of fluctuating isobars and mean isopycnals.…”

Self-Reversed Scandium Lines as a Diagnostic Tool for Multicomponent HID Lamps

“…But even after decades of research the understanding of the physics inside the lamp is still challenging [Araoud 2010, Brok 2006, Dabringhausen 2005, Dreeben 2011, Hartel 1999, Wei␤ 2005, where the examination of a multi component plasma is a much more complex task compared to a 'simple' mercury HID lamp, which is the 'white mouse' of HID lamp research.…”

Acoustic Resonance Characterization and Numerical Model Including Acoustic Streaming in an HPS Lamp

“…Lamp AR experimental characterizations are also conducted so as to define AR zones and its detections necessary for ballast design [7][8][9]. In [10] a model of HID lamp including the acoustic instabilities has been performed.…”