Numerical Study of the Effective Impedance of a Thermoacoustic Stack

Author: Worlikar Aniruddha S.   Knio Omar M.   Klein Rupert  

Publisher: S. Hirzel Verlag

ISSN: 1610-1928

Source: Acta Acustica united with Acustica, Vol.85, Iss.4, 1999-07, pp. : 480-494

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

The force balance in the neighborhood of an idealized thermoacoustic stack is analyzed using two-dimensional unsteady flow simulations. The numerical model is based on a small-Mach-number approximation to the compressible Navier-Stokes equations; it ignores acoustic wave propagation within the stack but retains bulk compressibility and the convective nonlinearity of the original conservation equations. The effects of long wave acoustic pulses which drive the stack flow are taken into account through suitable velocity boundary conditions. The computations are used to characterize the effective impedance of the stack and to analyze its dependence on operating conditions and stack configuration parameters. Results are compared to semi-heuristic explicit formulas based on the linear theory.