Discrete Cooling of Supports and Multi-Layer Insulation in Helium Dewars
Methods of optimizing location of boil-off gas cooled support and insulation heat intercepts to minimize heat leak to helium dewars are discussed. Analyses include use of separate gas streams for support and insulation cooling and the much simpler case of one stream for both purposes. Calculations are made for stainless steel and epoxy-fiberglass supports with ratios α = (AILS)/(ASLI), ranging from 25 × 103 to 800 × 103. Heat intercept locations are optimized for one through six intercepts. Calculations include independent location of intercepts on the supports and insulation and the effect of positioning the intercepts with equal length/thickness fractions. Results are presented graphically for easy use by dewar designers.
KeywordsTotal Heat Petroleum Helium
Unable to display preview. Download preview PDF.
- 1.A. Bejan, Discrete cooling of low heat leak supports to 4.2K, Cryogenics, May 1975•Google Scholar
- 2.R.A. Hopkins and W.F. Brooks, Orbital Performance of a One-year Lifetime Superfluid Helium Dewar Based on Ground Testing and Computer Modelling, in: “Advances in Cryogenic Engineering, Vol. 27,” Plenum, New York (1982).Google Scholar
- 3.“Handbook on Materials for Superconducting Machinery, Mechanical, Thermal, Electrical and Magnetic Properties of Structural Materials”, Metals and Ceramics Information Center, Battelle’s Columbus Laboratories, November 1974.Google Scholar
- 4.M.B. Kasen, G.R. MacDonald, D.H. Beekman Jr., and R.E. Schramm, Mechanical, Electrical, and Thermal Characterization of G-10CR and G-11CR Glass-Cloth/Epoxy Laminates Between Room Temperature and 4K, in: “Advances in Cryogenic Engineering, Vol. 26,” Plenum, New York (1980), p. 235.Google Scholar