Analysis of thermoacoustic phenomenon using concentrated mass model

Abstract

In general acoustic analysis, temperature of the air is often assumed to be constant. However, in some cases, the relationship between sound waves and temperature cannot be ignored. For example, a temperature gradient in an acoustic tube can generate self-excited vibrations of the air. A temperature gradient can also be generated by the input of sound waves. Engines and refrigerators that apply these phenomena can use exhaust heat as a drive source, so that they are expected as thermoacoustic devices with little adverse effect on the environment. Thermoacoustic devices have been actively studied in recent years, and efficient analytical methods including non-linearity of sound waves are still required. In this study, we propose an analysis method of thermoacoustic phenomena using a concentrated mass model. This model consisted of masses, springs, and dampers, and efficiently analyses thermoacoustic phenomena as a vibration system. In addition, this model is suitable for non-linear analysis and coupled analysis with other vibrating bodies. In this paper, we formulated an acoustic tube with a temperature gradient using the proposed model and verified the validity of the model by numerical calculations.