Integral methods of calculation of heat transfer and drag under conditions of turbulent pipe flow of liquid of variable properties: Steady-state and quasi-steady-state flows in a round pipe with constant temperature on the wall
Abstract:
An integral method is suggested for the calculation of heat transfer and drag under conditions of flow of dropping liquid and gas in a pipe with constant wall temperature. It is found that the kind of thermal conditions on the wall $(T_{\text{wall}} = \text{const}$ or $q_{\text{wall}} = \text{const})$ has insignificant effect on the Nusselt number and coefficient of friction drag for a steady-state flow of dropping liquid of variable viscosity. For a quasi-steady-state pulsating flow of dropping liquid, the thermal boundary conditions have an appreciable effect on the Nusselt number alone; in so doing, the degree of this effect increases with the oscillation amplitude and hardly depends on the temperature factor. For steady-state and quasi-steady-state flows of gas at high temperature factors, the values of heat transfer and drag at $T_{\text{wall}} = \text{const}$ differ significantly from those at $q_{\text{wall}} = \text{const}$.
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