Heat Transfer from Metal to Supercritical Helium

Summary A cooling system is described for controlling the temperature of supercritical helium. It was used to determine the heat transfer by free convection from horizontal metal cylinders to helium. The measurements at various temperatures indicated that maximum heat fluxes occur at certain pressures. The heat transfer to supercritical helium is at a maximum near the critical point (5.22°K, 2.30 atm.). At the higher temperatures the maxima of the heat transfer curves occur at higher pressures; they then have smaller absolute values. At small excess temperatures, δT