Role of size on the relative importance of fluid dynamic losses in linear cryocoolers

Cryogenic Engineering Conference 2017

材料科学;物理学

Kirkconnell, Carl^1 ; Ghavami, Ali^2 ; Mostafa Ghiaasiaan, S.^2 ; Perrella, Matthew^2

West Coast Solutions, 6741 Brentwood DR, Huntington Beach

CA

92648, United States^1

Georgia Institute of Technology, G.W. Woodruff School of Mechanical Engineering, Atlanta

GA

30332, United States^2

关键词: Computational fluid dynamics analysis;    Cryocooler system;    High frequency HF;    Lower frequencies;    Pulse tube coolers;    Pulse tube cryocoolers;    Stirling cryocoolers;    Thermodynamic model;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/278/1/012173/pdf
DOI  :  10.1088/1757-899X/278/1/012173

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Thermodynamic modeling results for a novel small satellite (SmallSat) Stirling Cryocooler, capable of delivering over 200 mW net cooling power at 80 K for less than 6 W DC input power, are used in this paper as the basis for related pulse tube computational fluid dynamics (CFD) analysis. Industry and government requirements for SmallSat infrared sensors are driving the development of ever-more miniaturized cryocooler systems. Such cryocoolers must be extremely compact and lightweight, a challenge met by this research team through operating a Stirling cryocooler at a frequency of approximately 300 Hz. The primary advantage of operating at such a high frequency is that the required compression and expansion swept volumes are reduced relative to linear coolers operating at lower frequencies, which evidently reduces the size of the motor mechanisms and the thermodynamic components. In the case of a pulse tube cryocooler, this includes a reduction in diameter of the pulse tube itself. This unfortunately leads to high boundary layer losses, as the presented results demonstrate. Using a Stirling approach with a mechanical moving expander piston eliminates this small pulse tube loss mechanism, but other challenges are introduced, such as maintaining very tight clearance gaps between moving and stationary elements. This paper focuses on CFD modelling results for a highly miniaturized pulse tube cooler.