Optimizing hydraulic radius and acoustic field of the thermoacoustic engine

It is well known that the acoustic field and the hydraulic radius of the regenerator play key roles in thermoacoustic processes. The optimization of hydraulic radius strongly depends on the acoustic field in the regenerator. This paper investigates the synthetical optimization of the hydraulic radius and the acoustic field which is characterized by the ratio of the traveling wave component over the standing wave component. In this paper, the normalized expressions of acoustic power gain and second law efficiency are derived and calculated, and then some useful calculated results are discussed. Some conclusions have been obtained, which are of significance to explain the optimum work conditions of existing engines and to guide the designs of new thermoacoustic devices. Finally, the operation factor of regenerator is discussed, which is a dimensionless parameter defined in this paper and highly relates to the working condition of the regenerator.