ABSTRACT
Many engineering applications involve external laminar flow heat transfer; such applications include electronic component cooling and plate-type heat exchangers. The similarity and integral methods are presented as solution techniques for laminar, external flows. The similarity momentum and energy equations with proper velocity and thermal boundary conditions (BCs) are derived. The discussion begins with flow over a flat plate (zero-pressure gradient flow) with a constant surface temperature. The similarity solution is then extended to include various constant pressure gradient flows (such as flow acceleration or deceleration) with variable surface temperature BCs. These flows can be solved using the fourth-order Runge–Kutta method in order to obtain the velocity and temperature profiles with the forced convection boundary-layer flow. For the integral method, the momentum and energy integral equations are derived from mass, force, and heat balances across the boundary layer. These equations can be solved to provide approximations of the friction factor, heat transfer coefficient, viscous boundary layer thickness, and thermal boundary layer thickness. High velocity flow across a cylinder or over a flat plate is also presented and this leads to discussion of the stagnation temperature, adiabatic wall temperature, recovery factor, and heat transfer in high speed flows.
