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The effect of noncondensables upon the laminar film condensation of vapor-gas flow inside a horizontal tube were investigated. The analysis was undertaken for the continuity, momentum and the thermal energy with its boundary conditions for the condensable film. Also the diffusion equation with its boundary conditions for the gas phase. The resulting partial differential equations were solved numerically by finite difference technique using a computer program for a wide range of parameters. Numerical results were obtained for the heat transfer coefficients with and without noncondensable for a wide range of parameters. It was found from the numerical results that the heat transfer coefficients inside the tube of the horizontal condenser are strongly dependent upon the axial and circumferential position. The noncondensable reduces the heat transfer and these reductions are accentuated at low operating pressures. For small steam velocities, a severe effects of the noncondensables are expected at the back end of the tube.

A new trend to a brine heater design with a sprayed saline water on hori-: •zontal tubes, where condensation takes place inside the tube bundle while • the cooling evaporating film flows over the outside of the tubes. For the condensation inside and film evaporation outside the tube, the analysis of potion and energy equations with each boundary conditions and the laminar theory were undertaken. The resulting system of first order ordinary differential equations were solved numerically by computer program using Runge-Kutta-type method for a wide range of parameters. It was found from the. numerical results that the heat transfer coefficients for the condensation : and evaporation were inversly proportional to the film thickness around the tube. The average overall heat transfer coefficients increases by decreasing the saline water Reynolds number and the tube radius.

The laminar flow of both fully developed and uniform entry velocity pro-:files in a permeable annuli was studied. The set of continuity, momentum and energy equations with its boundary conditions were solved numerically by computer program using finite difference method for a wide range of :parameters. It was found from the numerical results that for the inlet parabolic velocity profile the axial velocity profile near the wall along the annuli increases due to suction and decreases due to injection. The axial pressure drop along the annuli with suction is smaller than it with :injection. The local Nusselt number at the entry region increases due to 'suction and decreases due to injection through the inner wall of annuli.