Abstract
Frequently heat exchangers in engine rooms are used in various conditions which are considerably different from their designed conditions. This tendency has increased recently, as ships running with reduced speeds increase in number. Therefore it is necessary to estimate their behaviours under such conditions easily and instantly. In these cases, without deep understanding of their natures, the estimation by rule of thumb may often lead to wrong results.
In the paper the estimation method, simple but relatively correct, are shown by the utilization of the empirical fact that the coefficient of overall heat transmission is proportional to (the fluid speed in tube) n or similar. In addition to the fundamental equations, shown are the individual ones for fuel oil heaters, feed water heaters, lubricating oil coolers and Butterworth sea water heaters as well as calculation examples for them.
