Heat transfer in pipes under conditions of supercritical pressures of the heat carrier and thermal load varying along the length

The possibility is demonstrated of using relations of Duhamel integral type (superposition principle) for calculating the heat transfer for a turbulent flow in a pipe of a heat carrier at supercritical pressure. Experimental Nusselt numbers and values of the wall temperature obtained under conditions of linear increase or decrease of the thermal flux density along the length of the pipe are compared with values calculated in analogy with the superposition method.