抄録
Numerical solutions are presented for the flow and heat transfer problems of laminar forced convection for liquids in rectangular ducts by use of several correlative equations for viscosity-temperature as used in the studies of the circular tube, where the fully developed velocity and temperature fields, under the boundary conditions of axially uniform wall heat flux and peripherally uniform wall temperature, are assumed. The effects of viscosity variations on the profiles of velocity and temperature, the friction factor and the Nusselt number are summarized as follows: i) the velocity profile is strongly affected by the viscosity ratio based on the wall and cup mixing temperature (μw/μm), whereas the temperature profile is affected weakly, and ii) the relationship of f/fcp vs. μw/μm for various aspect ratios is in good agreement with that of the circular tube as reported by Shannon et al. and Deissler, in the region of μw/μm<10 where fcp is the friction factor for the case of constant viscosity. On the other hand, the relationship of Nu/Nucp vs. μw/μm is different from that of the circular tube, except in the region where μw/μm is closer to unity, and its difference is remarkable in a larger aspect ratio.
