Fully Developed Flow and Heat Transfer in Ducts Having Streamwise-Periodic Variations of Cross-Sectional Area

Abstract

The concepts of fully developed flow and heat transfer have been generalized to accommodate ducts whose cross-sectional area varies periodically in the streamwise direction. The identification of the periodicity characteristics of the velocity components and of a reduced pressure function enables the flow field analysis to be confined to a single isolated module, without involvement with the entrance region problem. A similar modular analysis can be made for the temperature field, but the periodicity conditions are of a different nature depending on the thermal boundary conditions. For uniform wall temperature, profiles of similar shape recur periodically. On the other band, for prescribed wall heat flux which is the same for all modules, the temperature field itself is periodic provided that a linear term related to the bulk temperature change is subtracted. The concepts and solution procedure for the periodic fully developed regime were applied to a heat exchanger configuration consisting of successive ranks of isothermal plate segments placed transverse to the mainflow direction. The computed laminar flow field was found to be characterized by strong blockage effects and massive recirculation zones. The fully developed Nusselt numbers are much higher than those for conventional laminar duct flows and show a marked dependence on the Reynolds number.

A helical tow model and numerical simulation of on-line thermal curing of thermoset composites in filament winding

“…For the solution of each point at each grid line, the standard TDMA is applied in the r and s directions. A CTDMA (Cyclic TDMA) [26,27] that is effective for periodic problems, in which the beginning and the end of the computational domain are the same, is applied in the h direction. Because the source term and boundary condition are functions of temperature, they are calculated at each iteration step to obtain new values.…”

“…(27), convection terms account for the motion of the tow in filament winding. If the moving speed of tow in its axial direction is given as V t , then the angular velocity of mandrel rotation is…”

Development of Single Phase Heat Transfer Correlations for Water & R134a in Rectangular Channel with Smooth Wavy Fin

“…In second phase the j value is estimated for the same range of Reynolds number using energy equation. In order to overcome the entrance effect, the concept of periodic fully developed flow as suggested by Patankar et al [19] is implemented for the flow analysis. The pressure drop for unit length is estimated from ANSYS CFD initially and is used for estimation of the friction factor f as per Kays and London [2] procedure.…”

Numerical Analysis of Thermal and Aerodynamic Fields in a Channel with Cascaded Baffles

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