A novel technique of Computer Aided Parametric Analysis (CAPA) is developed for driving simple and acurate empirical formulas with the aid of numerical solution for a complex convective fow system. To demonstrate the validity of the technique, a classical mixed convection problem is a uniformly heated hoziontal square channel is chosen. The thermal fluid flow is hydrodynamically and thermally fully developed. The axial pressure and temperature gradients are constant, and the peripheral wall temperature is assumed uniform. The secondary flow is produced by the buoyancy force caused bythe density gradient. The CAPA technique employs sign, constant factor and multiple term relationship for formulating a set of algebraic equations. It is easier to solve the set of algebraic equations for the characteristic quantities than to solve the original system of partial differential equations. The flow drag and the heat transfer coefficients can also be derived by using these characteristic values. The remaining undetermined constant factors for the characteristic velocities temperaure friction factor, and heat transfer coefficient are then decied by using two data in the numerical solution of the governing partial differential equations (or by the experimental data if they are available). Comparisons of the CAPA data with the numerical solution are made.
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