Numerical studies on sizing/ rating of plate fin heat exchangers for a modified Claude cycle based helium liquefier/ refrigerator

26th International Cryogenic Engineering Conference & International Cryogenic Materials Conference 2016

材料科学;物理学

Goyal, M.^1,2 ; Chakravarty, A.^1 ; Atrey, M.D.^2

Cryo Technology Division, Bhabha Atomic Research Centre, Mumbai, India^1

Mechanical Engineering Department, IIT Bombay, Mumbai, India^2

关键词: Axial heat conduction;    Combined effect;    Compact plates;    Iterative process;    Liquefaction systems;    Off-design performance;    Plate-fin heat exchanger;    Refrigeration mode;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/171/1/012091/pdf
DOI  :  10.1088/1757-899X/171/1/012091

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Performance of modern helium refrigeration/ liquefaction systems depends significantly on the effectiveness of heat exchangers. Generally, compact plate fin heat exchangers (PFHE) having very high effectiveness (>0.95) are used in such systems. Apart from basic fluid film resistances, various secondary parameters influence the sizing/ rating of these heat exchangers. In the present paper, sizing calculations are performed, using in-house developed numerical models/ codes, for a set of high effectiveness PFHE for a modified Claude cycle based helium liquefier/ refrigerator operating in the refrigeration mode without liquid nitrogen (LN2) pre-cooling. The combined effects of secondary parameters like axial heat conduction through the heat exchanger metal matrix, parasitic heat in-leak from surroundings and variation in the fluid/ metal properties are taken care of in the sizing calculation. Numerical studies are carried out to predict the off-design performance of the PFHEs in the refrigeration mode with LN2pre-cooling. Iterative process cycle calculations are also carried out to obtain the inlet/ exit state points of the heat exchangers.