Speaker
Description
With the rapid progress of superconducting quantum computing, the cryogenic technology capable of providing appropriate cooling in the millikelvin temperature region is desirable. The cryogen-free dilution refrigerator featuring high reliability, long lifetime, and continuous cooling has become a promising cryocooler candidate.
As one of the key components of the dilution refrigerator, the orifice is used to control the flow and liquefy helium-3, which is crucial to achieving the millikelvin temperature. In order to analyze the dilution cycle and improve the refrigeration performance, a throttling model is established which focuses on the influence of complex physical properties of helium-3 and the dilution refrigeration cycle from supercritical pressure to saturation state. The effects of the diameters and thicknesses of the orifice on the flow rate are studied, and the influences of different inlet pressures and temperatures on the throttling process are discussed. The orifice throttling experiment is then conducted to verify the rationality of the model, and the results show that the simulation results agree with the experimental ones.
The theoretical analyses and experimental studies are described in detail, and the effects of the developed orifice on the performance of the dilution refrigerator will be presented and discussed. It is indicated that the throttling model can reasonably predict the flow rate under different structural, dimensional and operating conditions, and is helpful to the design and optimization of the cryogen-free dilution refrigerator.
Keywords: Dilution refrigerator; Helium-3; Throttling process; Liquefaction rate
