@article{ajme2020832,
author={Adiutori, Eugene F.},
title={Why Heat Transfer Coefficients Are Unnecessary and Undesirable, and How Heat Transfer Problems Are Solved without Them},
journal={American Journal of Mechanical Engineering},
volume={8},
number={3},
pages={106--110},
year={2020},
url={http://pubs.sciepub.com/ajme/8/3/2},
issn={2328-4110},
abstract={For 200 years, convective heat flux <i>q</i> has been calculated by multiplying heat transfer coefficient <i>h</i> times boundary layer temperature difference &#916;<i>T</i>. Since <i>h </i>times &#916;<i>T </i>equals <i>q, h must</i> be a symbol for<i> (q/</i>&#916;<i>T)</i> because <i>(q/</i>&#916;<i>T) </i>times<i> </i>&#916;<i>T</i> equals <i>q.</i> <i>h</i> (ie <i>q/</i>&#916;<i>T</i>) is generally calculated from correlations derived from experiments in which <i>q</i> data and &#916;<i>T</i> data are used to obtain <i>(q/</i>&#916;<i>T){</i>&#916;<i>T}</i> correlations-ie <i>h{</i>&#916;<i>T}</i> correlations. (It is not possible to obtain <i>h</i> data because <i>h</i> is not a parameter. <i>h</i> is the ratio of <i>two </i>parameters). Heat transfer coefficients are <i>unnecessary</i> and <i>undesirable</i>. It is self-evident that any problem that can be solved using <i>q, q/</i>&#916;<i>T (ie h)</i>, and &#916;<i>T</i> can also be solved using only <i>q</i> and &#916;<i>T</i>. Therefore <i>h</i> (ie <i>q/</i>&#916;<i>T</i>) is <i>unnecessary.</i> <i>h</i> (ie <i>q/</i>&#916;<i>T</i>) is <i>undesirable</i> because, when <i>q</i> is a nonlinear function of &#916;<i>T</i> (as in free convection, condensation, and boiling), <i>h</i> (ie <i>q/</i>&#916;<i>T</i>) is an extraneous <i>variable</i>, and it <i>greatly</i> complicates problem solutions. When <i>h</i> has been abandoned, convective heat flux is determined from <i>q{</i>&#916;<i>T}</i> correlations that result from <i>q</i> data and &#916;<i>T</i> data, or from the transformation of <i>h{</i>&#916;<i>T}</i> correlations. (Transformation from <i>h{</i>&#916;<i>T}</i> correlations to <i>q{</i>&#916;<i>T}</i> correlations requires that <i>h</i> be replaced by <i>q/</i>&#916;<i>T</i>, and that <i>q</i> and &#916;<i>T</i> be separated.). The text includes example problems that validate the conclusion that <i>h</i> (ie <i>q/</i>&#916;<i>T</i>) is unnecessary and undesirable, and demonstrate that the solution of nonlinear problems is much simpler if <i>h</i> is abandoned.},
doi={10.12691/ajme-8-3-2}
publisher={Science and Education Publishing}
}