Numerical Simulation of an Acoustically Driven Resonator With Internal Thin Parallel Plates

Heat transfer and flow characteristics in a two-dimensional resonator with inside thin plates due to acoustic excitations are investigated numerically. The effect of the presence of the internal thin plates in the resonators is then studied. Such parallel plates (stacks) have been used in acoustic resonators for developing thermoacoustic refrigerators and thermoacoustic engines. A fully compressible form of the Navier-Stokes equations is considered for the numerical model and an explicit time-marching algorithm is used to track the acoustic waves and energy flux. Numerical solutions are obtained by employing a highly accurate flux corrected transport (FCT) algorithm. In the present model, the acoustic waves are induced by vibrations of the left wall, and the right wall is stationary. By neglecting the effect of side walls, the top and bottom boundary conditions are assumed to be symmetric. No simplifying assumption is made regarding the existence of the acoustic field. The interaction of acoustic standing waves with the internal parallel plates produces a temperature difference between the two ends which can be used for refrigeration or to do work (as a heat engine). The temperature differences are found to be significantly dependent on the location, length and gap of the internal plates. The model developed can be used for the analysis of flow and temperature fields driven by acoustic transducers, as well as in the design of high-performance resonators for thermoacoustic refrigerators and engines.