What Exactly is the Nusselt Number in Convective Heat Transfer Problems and are There Alternatives?

What Exactly is the Nusselt Number in Convective Heat Transfer Problems and are There Alternatives?

The often used Nusselt number is critically questioned with respect to its physical meaning. Based on a rigorous dimensional analysis, alternative assessment numbers are found that in a systematic way separately account for the quantitative and qualitative aspect of a heat transfer process. The qualitative aspect is related to the entropy generated in the temperature field of a real, irreversib...

Abram S . Dorfman Conjugate Problems in Convective Heat Transfer

Transient Convective Heat Transfer

In nature, as well as within the human-made thermal systems, the time-variable regimes are more commonly encountered, if not always, than the permanent regimes. Nevertheless, studies in convection are still more frequent in the permanent regimes, undoubtedly due to the related difficulties in calculation in terms of time and cost of computation. One may distinguish two categories of time-depend...

Experimental Investigation on Turbulent Heat Transfer, Nusselt Number and Friction Factor Characteristics of Square Ducts

This paper presents the results of an experimental investigation of heat transfer to the airflow in the square duct. The main purpose of this study is influence of square ducts on the convective heat transfer mechanism. Under this investigation friction factor and the Nusselt Number were calculated. The reason that square ducts increase the fluid flow turbulence near the wall and also increase ...

A Hybrid Uncertainty Propagation Scheme for Convective Heat Transfer Problems

A computational analysis of convective heat flux around an array of cylinders in a high Reynolds number flow is presented; we assume that both the inflow and the wall heat flux conditions are specified with a margin of uncertainty and our objective is to quantify the resulting effect on some functional of interest, mainly the cylinder wall temperature. We introduce a hybrid uncertainty propagat...