Acoustic Characteristic Investigation On Thermoacoustic Elements Based On Fluent

Themoracoustic engine is a new type of engine. It is based on thermoacoustic effect. Due to its simple structure, high reliability, no pollution , no moving part , the thermoacoustic engine has many advantages compared to the traditional engines.Firstly, the paper reviewed the thermoacoustic theory and the technical development, and introduced the thermoacoustics elementary knowledge and thermoacoustic phenomenon principle. At same time, the paper analyzed the thermodynamic cycle of thermoacoustic engine.DeltaE is particular calculated software for thermoacoustic, but it is based on linear assumption, and neglected entry effect, so it is deficiency for studying on acoustic field in regenerator. We used Fluent to simulate the distribution of acoustic field.In order to verify that Fluent is feasibility for simulating the distribution of acoustic field in thermoacoustic systems, we calculated the pressure distribution along the straight resonator which terminated in a rigid wall and a large spherical volume respectively. The results were agreed well with the theoretic analysis. Then we simulated an experimental system by using two measured values as the input and output values. The simulated results were agreed well with the other measured values. It indicates that the means is feasible and the programs are right. Base on this, we studied two problems:1. How the shape of the resonator effects on acoustic field of thermoacoustic system. We made numerical analysis to the standing wave thermoacoustic resonator, including straight tubes, cone-shape tubes, and exponential tubes, and obtained the pressure distribution along the tubes. The results indicated that the reducer can increase pressure magnitude. This high pressure magnitude can satisfy to the need of pulse-tube refrigerator. The results also indicated that the pressure magnitude would increase as the angle of cone increase. 2. We studied on the flow characteristic in regenerator. We carried on a simple numerical analysis to the instantaneous friction coefficient of the oscillating flow in the parallel regenerator. Established a two dimension model, and studied on the pressure and velocity's distribution in regenerator by Fluent. At the same time we calculated the instantaneous friction coefficient of oscillating flow in the regenerator. The results indicated that the pressure magnitude and velocity magnitude are not a sine distribution anymore, but a linear distribution; the friction coefficient is a function of time and location; there is an obvious entry effect at the two end of the regenerator.