An analytical solution has been obtained for the longitudinal fully developed laminar flow between cylinders arranged in triangular or square array. Numerical results for the pressure drop and the friction factor are given over a wide range of spacing-to-diameter ratios. For large spacings the results can be represented by a single expression independent of the type of array. Plots are also given of velocity distributions and of the variation of the local shear stress around the periphery of a cylinder.
The effects of an axial magnetic field on the flow and heat transfer about a rotating disk have been analyzed. It is found that the presence of the magnetic field significantly decreases the flow velocities; but increases the torque required to maintain steady rotation of the disk. The heat transfer is also decreased by the magnetic field, with greater redutions occurring for low Prandtl number fluids.
The problem of laminar-film condensation on a vertical plate is attacked using the mathematical techniques of boundary-layer theory. Starting with the boundary-layer (partial differential) equations, a similarity transformation is found which reduces them to ordinary differential equations. Energy-convection and fluid-acceleration terms are fully accounted for. Solutions are obtained for values of the parameter cpΔT/hfg between 0 and 2 for Prandtl numbers between 1 and 100. These solutions take their place in the boundary-layer family along with those of Blasius, Pohlhausen, Schmidt and Beckmann, and so on. Heat-transfer results are presented. It is found that the Prandtl-number effect, which arises from retention of the acceleration terms, is very small for Prandtl numbers greater than 1.0. Low Prandtl number (0.003–0.03) heat-transfer results are given in Appendix 2, and a greater effect of the acceleration terms is displayed.
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