Numerical simulation of a thermoacoustic couple

Ahmed Abd El-Rahman , Ehab Abdel-Rahman

Here we report a 2D computational fluid dynamics simulation of the non-linear oscillating-flow behavior in a helium-filled half-wavelength standing thermoacoustic refrigerator. The finite-volume method is used, and the solid and air domains are represented by large numbers of quadrilateral and triangular elements. The calculations assume a periodic structure to reduce the computational cost and apply the dynamic mesh technique to account for the oscillating adiabatic equivalent wall boundaries. The simulation uses an implicit time integration of the full unsteady compressible flow equations with a conjugate heat transfer algorithm (ANSYS FLUENT). A Typical run involves 12000 elements and a total simulation time of five seconds. Simulation Results for drive ratios $Dr=0.28\%-2\%$ are compared to the Swift linear theory and the numerical analysis of Worlikar et al., and show better agreement with the experimental values of Atchley. A maximum cooling effect of three degrees is predicted at a non-dimensional wave number $kx=3 \pi/4$, measured from the resonator rigid end. This simulation provides an interesting tool for understanding the bulk and micro-structural flow behavior in TAR, characterizing and optimizing their performance, and building models of thermoacoustic flow analysis.

Mots clés: thermoacoustic; Computational fluid dynamics; numerical simulation; CFD

Domaines: Acoustique [physics.class-ph]

Ahmed Abd El-Rahman, Ehab Abdel-Rahman. Numerical simulation of a thermoacoustic couple. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810707⟩