Transient behaviour of an impulsively heated fluid

Abstract

Approximate as well as reasonably exact numerical solutions of the equation of conservation have previously predicted that sudden heating of a solid surface adjacent to a region of gas will generate a slightly supersonic wave with small positive amplitudes in pressure, temperature and density, and thereby a small mass velocity in the direction of wave propagation. If the gas is confined by a second parallel surface, the wave is predicted to be reflected repeatedly from both surfaces and to decay slowly due to viscous and thermal dispersion. This process, which has been termed thermoacoustic convection, is presumed to result in transient heating of the confined gas and heat transfer through it at rates greatly exceeding that of pure thermal conduction. The current work constitutes the first quantitative experimental confirmation of this behaviour. Numerical solutions obtained for support and guidance of the experimental work define for the first time the conditions required for the generation of a wave of significant strength.

One-dimensional numerical simulation of thermoacoustic engine with flux-corrected transport algorithm

“…Compared with Brown and Churchill's experiments [4,16], a constant time impulse heat on the wall inducing the thermoacoustic wave is qualitatively agreed in Fig. 2.…”

“…Given the comprehensive nonlinear physical mechanisms in the generation and propagation of thermoacoustic wave, a simple calculation example is provided to check the present algorithm, which is just the same as Brown et al [4] used. The initial condition of the cavity is T 0 = 300 K and P 0 = 0.101 MPa.…”

“…Considering that the linear theory could not accuracy deal with the nonlinear characters of thermoacoustic engines, the nonlinear theory has been developed. Brown et al [4] in 1993 simulated thermoacoustic effects, demonstrating that their numerical algorithm presented a real determination possibility in this respect. Lager et al [5] used a finite-differences control-volume method to simulate the periodic wall heating phenomena in 1993.…”