Wenjie Zhou Graduate Student Mechanical Engineering Room: 1327 ERB Email: wzhou42@wisc.edu Thesis: Continuously Variable Inertance Tubes for Pulse Tube Cryocoolers

Project Significance Inertance tubes introduced as phase-shifting mechanism for pulse tube refrigerators in early 1990’s Models and experiments demonstrate adequate agreement for design capabilities Phase shift is quite sensitive to geometry parameters of length and diameter for a given frequency and acoustic power Continuously variable phase shift advantage As built and assembled, the inertance tube may not provide the desired or expected phase shift Adjustable phase may enable accelerated cool down or alternate operating conditions.

Variable Inertance Tube Configuration Mass Flow Measurement Device

Experimental Test Discussion Future Work ~35° phase change @ 27 Hz 1.Continuously variable length produces nearly linear, continuous phase change; 2. Variable length is also accompanied by change in effective diameter. Future Work 1. Increase the pressure drop between P1 and P2; 2. Optimize the phase angle for the pulse tube cryocooler. 3. Explore additional configurations of adjustable inertance tubes ~35° phase change @ 27 Hz