Transient heat-transfer problems are not easily solved without applying complicated differential equations. Computer programs today handle much of this analysis. But how can you apply these programs to constantly changing everyday problems? Basically, you can’t.

Many years ago when I attended a meeting of the American Flame Research Committee (AFRC), I met Professor Hoyt Hottel, then retired from MIT. Professor Hottel, if you are unaware, beside being one of the founders of the AFRC, was one of the great minds that developed much of the modern radiant heat-transfer analysis along with much of the basic research in radiant heat transfer from gases. Only at the end of his career did the earliest computers become available for scientific research. So his work was done the hard way.

The lasting comment that Professor Hottel left me with during his discussion was that you had to be able to handle the most complicated analysis with simple concepts that you could calculate “on the back of an envelope.” Otherwise, how could you have any faith in a computer printout? As we all know – garbage in, garbage out. So as a manager of complex technology, how do you know if the results you and/or your staff get make any sense? Without the understanding of the very basic fundamentals, you don’t.

When I entered my professional life, we didn’t have calculators. Computers, when they did exist, were confined to the accounting department for payroll and accounting calculations. We used slide rules. Most of you reading this have no idea how they work, but leave it to say you multiply and divide by adding and subtracting logarithms. Therefore, you had no evaluation on where the decimal point belonged. You had to carry in your head the order of magnitude of each calculation. This turned out to be great discipline for evaluating computer results. All of my earliest designs were done on a slide rule.

More on this next week.