HEAT AND MASS TRANSFER ENHANCEMENT IN LAMINAR FORCED CONVECTION WET CHANNEL FLOWS WITH UNIFORM WALL HEAT FLUX

In the given paper, results of numerical investigation of fluid flow and conjugate heat and mass transfer in a cell of a direct evaporating cooler of air in the channel between two parallel plates are presented. Two-dimensional stationary Navier–Stokes and energy and diffusion equations for a laminar regime of flow have been solved. The effects of the Reynolds number (Re = 50–1000), temperature (T0 = 10–40°C), and humidity of air (φ0 = 0–50%) at the inlet and the values of a thermal flux on the wall [q* = (-0.1)–(+ 0.2)] on the rate of evaporation on a wet wall were studied. It is shown that vapor concentration and temperature of air at the channel exit grow on increase of the additional thermal flux at the wall. Thus, a normal vapor mass flux on surfaces also grows, which points to the more effective process of wall drying. The paper studies the analogy between the processes of heat and mass transfer and friction on a surface with phase transitions in the presence of additional heat supply to the evaporating surface. The results of calculations are discussed in detail and practical recommendations on optimization of evaporating cooling are given.

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