摘要 : The Chilton-Colburn analogy is very helpful for evaluating the heat transfer in internal forced flows. The Chilton-Colburn analogy between the Chilton-Colburn j-factor for heat transfer, j_H (St·Pr~(2/3)) and the Fanning friction ... 展开 The Chilton-Colburn analogy is very helpful for evaluating the heat transfer in internal forced flows. The Chilton-Colburn analogy between the Chilton-Colburn j-factor for heat transfer, j_H (St·Pr~(2/3)) and the Fanning friction factor (c_f) is popularly considered to hold when St·Pr~(2/3) equals to c_f/2, for constant fluid properties. The physical fluid properties, namely, viscosity and thermal conductivity, are generally a function of temperature for microconvective water flow due to a quite steep temperature gradient. Therefore, in present investigation, the validity of Chilton-Colburn analogy between St·Pr~(2/3) and c_f is re-examined for laminar microconvective flow with variable thermophysical fluid properties. It is observed that the Chilton-Colburn analogy is valid only for that portion of the flow regime, where St·Pr~(2/3) decreases with decreasing c_f. The validity of Chilton-Colburn analogy is also verified by the inverse dependence of Reynolds number (Re) with c_f. Two modified nondimensional parameters "∏_(Sµ) and ∏_(sk)" are emerged from the nondimen-sional form of 2D, steady-state, incompressible, pure continuum-based, laminar conservation of momentum and energy equations, respectively. These modified nondimensional parameters show the significance of variable fluid properties in momentum transport and energy transport. Additionally, the role of ∏_(Sµ) and ∏_(sk) in flow friction is also investigated. The higher values of ∏_(Sµ) and ∏_(sk) indicate the stronger influence on microconvection due to large variations in fluid properties. 收起