An experimental study of perforated plate heat transfer surfaces for application in recuperative beat exchangers for a solid hydrogen sorption cryocooler stage has been performed in order to identify suitable perforated surfaces, and to evaluate their performance. Friction factors and heat transfer coefficients have been obtained experimentally for a range of perforated surfaces with flow normal to the surface for Reynolds number less than 25. The single-blow transient testing method was used to obtain the heat transfer coefficients and the friction factors were obtained from isothermal pressure drop tests. The heat transfer data was processed using the "maximum-slope" technique. The data reduction model includes axial fluid and spacer conduction, compressibility and slip-flow effects, a step-wise temperature profile and assumes an exponential inlet temperature response. The results demonstrate a good thermal hydraulic performance for the surfaces tested at low Reynolds number. A model of a perforated plate counterflow exchanger which includes axial conduction and a step-wise temperature profile was used to evaluated the surfaces tested. A suitable perforated plate exchanger design has been identified which meets the design goal for a solid hydrogen sorption cryocooler stage of 95% efficiency.
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