Rogelio RosasM.S. Graduate StudentMechanical Engineering

Room: 1337 ERBEmail: rosas2@wisc.eduHometown: Los Angeles, CA

Thesis: Modeling a Superfluid Pulse Tube Refrigerator

MotivationInfrared and x-ray astrophysics missions have a need

to cool below 1 Kelvin in order to use instruments such as transition edge sensor (TES) bolometers, microwave kinetic inductance detectors (MKIDs), and microcalorimeters

Refrigerators with non-moveable parts are essential in low-gravity environments because of reliability and durability

Continuous cooling provides for longer available time to record data

System and Component ModelingA detailed numerical model

of the heat exchangers and pulse tubes will be developed

The final model will be inserted into the system level model and used to complete the design of hardware

The model will be used to determine required pump pressure ratio and volume, the size and effectiveness of the recuperative, cold end, and warm end heat exchangers, the pulse tube size, and the orifice size

Future WorkOnce system model has been optimized the

equipment will then be assembled to test a complete unit

Testing will include running the refrigerator with various cycle times and with 3He-4He mixtures with different 3He concentrations

Maps of performance (cooling power vs cold end and warm end temperatures) for different operating conditions will be generated

The data will be an analyzed and the system model will be refined using the experimental performance data