Equivalent isentropic expansion efficiency of real fluid subject to concurrent pressure drop and heat transfer

Cryogenic Engineering Conference 2017

材料科学;物理学

Knudsen, P.^1 ; Ganni, V.^1

Facility for Rare Isotope Beams (FRIB), Michigan State University (MSU), East Lansing

MI

48824, United States^1

关键词: Adiabatic expansion;    Counter-flows;    Effect of pressure;    Isentropic expansion;    Liquid streams;    Practical process;    Superconducting radio frequency;    Work extraction;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/278/1/012059/pdf
DOI  :  10.1088/1757-899X/278/1/012059

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Concurrent pressure drop and cooling of a super-critical or sub-cooled liquid stream can have the same effect as adiabatic expansion even though there is no work extraction. A practical implementation is as straight forward as counter-flow heat exchange with a colder fluid. The concurrent pressure drop need not be continuous with respect to the heat exchange, but may occur in a step-wise manner, in between heat exchange. Two aspects of this effect of pressure drop with heat transfer are examined; a thermodynamic and a practical process equivalent isentropic expansion efficiency. This real fluid phenomenon is useful to understand in applications where work extraction is either not practical or has not been developed. A super-critical helium supply, often around 3 bar and 4.5 K, being ultimately used as a superfluid (usually around 1.8 to 2.1 K) to cool a Niobium superconducting radio frequency cavity or a superconducting magnet is one such particular application. This paper examines the thermodynamic nature of this phenomenon.