Inertance tube optimization for kW-class pulse tubes

Growing interest in larger scale pulse tubes has focused attention on optimizing their thermodynamic efficiency. For Stirling-type pulse tubes, the performance is governed by the phase difference between the pressure and mass flow, a characteristic that can be conveniently adjusted through the use of inertance tubes. Unfortunately, data describing the optimized inertance geometry as a function of desired phase-shifts and acoustic power are not readily available. In this paper we present measurements of pressure, mass flow, and phase shift for inertance tubes subjected to kW-level acoustic power flows. This type of data can be used to characterize the optimal inertance geometry, length and diameter, for a desired phase shift and acoustic power. The measurements are compared to an inertance tube model based on transmission line theory.