Speaker
Description
A recent modification to the cylindrical threaded adjustable inertance tube for pulse tube refrigerators links the two helical flow channels existing between the threads of the inner and outer screws in parallel. The phase shifting performance of an earlier design that was limited by fluid leakage occurring between the channels, is now significantly improved by connecting the two channels in parallel. Measurements of the phase shift angle over the entire operating range of the adjustable device are compared with existing models. The models predict a phase angle shift between pressure and flow waves that range from -65 degrees to +40 degrees with the new parallel flow path configuration. By comparison, the original design could only obtain a phase angle shift between 0 and -30 degrees.