ABSTRACT
Many situations involving single-phase convection at cryogenic temperatures can be solved using techniques that are applicable at conventional temperature levels. One interesting problem in many cryogenic systems is heat transfer in the near-critical region. This chapter examines general problems involving singlephase convection and special problems involving heat transfer in the near-critical region. It reviews some dimensionless numbers such as the Reynolds number, Prandtl number, Nusselt number, Grashof number, and the Rayleigh number. For heat transfer in tube bundles in crossflow, the geometric arrangement influences the heat transfer coefficient. The tubes may be arranged in either a staggered or inline arrangement. In conditions in which there is no fan, blower, or other device to force the fluid to flow over a surface, motion of the fluid and convection heat transfer may occur as a result of the buoyancy force or the force due to the change in density of the fluid near the surface.
