Convective heat transfer from narrow leaves

Abstract

Convective heat transfer was measured from models of leaves of four species of arid-zone tree. The models were made of copper and were heated electrically. Measurements were made in still and moving air, and empirical expressions for the convective heat transfer coefficient he derived in each case. These expressions for he for still air differed from the simplified engineering formulae for flat plates. The four types of leaf, being small, long, and narrow, fell outside the range of sizes to which the simplified free convection formulae apply, and it was found that in each case the convective heat transfer was greater than the latter would predict. The validity of the formulae derived from the copper models was checked by using them to calculate the convection term in complete energy balances measured for real single leaves of similar size and shape to the models. © 1970 CSIRO.