Investigation of Thermoacoustic Performance of Standing and Traveling Wave Thermoacoustic Engines

A standing wave thermoacoustic engine was designed and constructed to examine the effect of curvature on thermoacoustic performance. Sound pressure level at the pressure node of the engine was recorded in conjuction with the temperature at the hot and ambient sides of the stack. Curvature was varied using flexible tubing from 0 to 45. It was found that the curvature had a negative effect on the thermoacoustic intensity, measured using the sound pressure level and the temperature difference between the hot and ambient sides of the stack. Additionally, a strong relationship between the sound pressure level and the temperature behavior was identified. The findings of the investigation were applied to a study of a traveling wave engine. A looped tube design was employed with a regenerator mounted in a straight section of the tube. Thermocouples were mounted in the regenerator to investigate the temperature behavior. Initial results of the thermoacoustic effect were established by calculating the difference in behavior between operation with oscillation and without. These were followed by an investigation of the relationship between the temperature behavior and the positioning of the regenerator in the looped tube. An optimal spacing was identified for positioning the stack in the straight portion of the tube