Investigation of unsteady-state heat transfer in a channel with saturated He-II: stepwise thermal load

Investigation has been made of the unsteady-state heat transfer in a channel with saturated He-2 in a counterflow (ρv=0) with local heat supply in the middle of the channel in form of the stepwise function. Unsteady-state He-2 temperature distributions along the channel, helium superheats as crisis precursors, delay times prior to the crisis onset have been determined. A numerical method is developed to solve the unsteady-state energy equation for He-2 with allowance for temperature-dependent thermophysical helium properies