Development and Characterization of a Low-Cost Sensors System for an Acoustic Test Bench

Existing acoustic test benches are usually costly devices based on proprietary designs, sensors, and acquisition devices. In this paper, a low-cost test bench for acoustic purposes is introduced. The design of the test bench takes into account not only the low-cost mechanical design, but also uses low-cost sensors and control boards. This test bench has been designed for a range of signals compatible with those used by thermoacoustic engines, but it can be useful for applications with similar requirements. Taking advantage of an auxiliary pressure reference, low-cost unidirectional differential pressure sensors can be used to significantly increase the accuracy of the sampling system. The acoustic and mechanical design and development are presented along with the sampling system and the sensors arrangement implemented. Both the sensor and sampling system are evaluated by comparison with a high-fidelity sound acquisition system. An unexpected effect on the time error values distribution of the low-cost acquisition system is found and described. Finally, the errors introduced by the system and the sensors in terms of time and pressure sampling are characterized. As a result, the low-cost system’s accuracy has been satisfactory assessed and validated for the conditions expected in thermoacoustic experiments in terms of frequency and dynamic pressure.

Thermoacoustic Energy Conversion Devices: Novel Insights

Thermoacoustic engines and refrigerators have many advantages. They use environment-friendly working gases, their design is simple, and they can operate quietly. However, they have many design characteristics from geometric parameters and operating conditions. Besides this, they still have low efficiencies and performance. This paper summarises important considerations of the design and presents the state-of-the-art developments in thermoacoustic energy conversion devices. This includes recent studies and designs of the thermoacoustic refrigeration devices towards more efficient thermoacoustic engines and refrigerators. New insights into the design of resonators, the different sources of the power sources, the different stack geometries and working mediums were considered. The challenges that face the development of thermoacoustic devices were also discussed. Far too little attention has been paid to looking at these devices comprehensively. In further research, the use of neural networks and metadata as optimisation methods could be a means of significantly increasing the performance of these devices. There is also abundant room for further progress in enhancing oscillatory heat transfer. Moreover, further recommendations and studies were proposed for a better understanding of the interrelationship between the geometric parameters and operating conditions.