In recent years, with the widespread adoption of hydrogen as a clean energy source, low-temperature hydrogen turbine expanders have played a crucial role in the production of liquid hydrogen. Currently, there is limited focus on the brake side, despite the interdependence and mutual influence between the brake impeller and the turbine impeller. To improve the efficiency and reliability of...
Pulse tube (or piston) expansion cryogenic refrigerators are a type of refrigeration equipment capable of highly reliable operation in low-temperature environments and are particularly suitable for medium-sized cooling requirements. In this type of refrigerator, intermittent flow cold storage surface heat exchanger is required to improve the refrigeration efficiency. In this research, we...
The storage and transportation of liquid helium inevitably lead to overpressure and leakage due to its extremely low boiling point and high evaporation rate, resulting in helium loss. By introducing cooling through a cryocooler, the thermal losses can be effectively reduced, potentially achieving ZBO(zero-boil-off). However, research on liquid helium lossless technology is still limited. This...
Throughout the progression of particle accelerator technology, there has been a significant upsurge in the demand for cooling capabilities within the superfluid helium temperature range. The integration of cold compressors not only minimizes the size of heat exchangers but also optimizes the utilization of cold exergy. In the context of multi-stage serial centrifugal cold compressors, the...
In view of cryocooler-dependent dry cooling of superconducting magnets and systems, efficient heat transfer devices that can function independent of the gravity effect are in high demand. One of the recent candidates gaining popularity are cryogenic pulsating heat pipes (PHP), synonymously called as oscillating heat pipes. These wickless heat pipes, made by simply meandering capillary tubes,...
Superconducting radio frequency (SRF) cavity technology is typically operated at 2 K temperature to minimize the RF surface loss by reducing the BCS resistance, thereby achieving a high-quality factor (Q0). To maintain a 2 K environment, LHe(liquid helium) is normally converted to saturated HeII by using a sub-atmospheric vacuum pumping system to pump down the pressure of the helium chamber to...
High speed turbo expanders for hydrogen and helium serve as critical components in large-scale cryogenic systems. Their efficient and stable operation directly determines overall system performance. Due to the low density and high enthalpy drop of hydrogen and helium, turbo expanders must operate at extremely high rotational speeds, to achieve high thermodynamic efficiency. Aerostatic bearings...
