Numerical simulation of a thermoacoustic refrigerator. I. Unsteady adiabatic flow around the stack

Journal Article · Sun Sep 01 04:00:00 EDT 1996 · Journal of Computational Physics

DOI:https://doi.org/10.1006/jcph.1996.0185· OSTI ID:478580

Worlikar, A S; Knio, O M ^[1]

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1. Johns Hopkins Univ., Baltimore, MD (United States)

A low Mach-number compressible flow model for the simulation of acoustically driven flow in a thermoacoustic stack is constructed. The model is based on the assumption that the acoustic wavelength is much larger than the characteristic hydrodynamic lengthscale. Thus, a simplified description of the flow is obtained which still retains the essential features of acoustically induced velocity oscillations near solid boundaries. A vorticity-based formulation of the governing equation is derived which relies on the Helmholtz decomposition of the velocity vector into irrotational and divergence-free components. Irrotational motion is used to represent the action of acoustic waves. Meanwhile the divergence-free velocity component is used to capture the nonlinear vortical perturbations due to no-slip boundaries. A simplified version of the model is applied to analyze unsteady flow in the neighborhood of an idealized thermo-acoustic stack which consists of a periodic array of thin plates placed in an acoustic standing wave. Computed results are used to analyze, for different stack configurations, the nonlinear response of the flow to different acoustic driving amplitudes and frequencies. In particular, it is shown that the flow is dominated by the motion of vortices which result from the shedding of boundary layers from the edges of the stack. The dependence of energy losses on stack configuration and operating conditions is also examined. 28 refs., 23 figs., 2 tabs.

• OSTI ID: 478580
• Journal Information: Journal of Computational Physics, Journal Name: Journal of Computational Physics Journal Issue: 2 Vol. 127; ISSN 0021-9991; ISSN JCTPAH
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
99 GENERAL AND MISCELLANEOUS
ACOUSTICS
COMPRESSIBLE FLOW
COMPUTERIZED SIMULATION
FLOW MODELS
HEAT TRANSFER
REFRIGERATORS
UNSTEADY FLOW