Effects of waffle height on the air-side performance of wavy fin-and-tube heat exchangers

An experimental study was carried out to examine the effects of the waffle height, including three different values of waffle height-1.18, 1.32, and 1 .58 mm-on the heat transfer and friction characteristics of typical fin-and -tube heat exchangers having wavy fins. A total of 13 samples of heat excha ngers, nine of them having wavy fins and the other four having plain fin co nfigurations, were tested. The test results indicated that the effect of wa ffle height on the heat transfer enhancement ratio, compared to the plain-f in counterpart, is pronounced only for smaller fin pitch and larger waffle height, while its effect on the pressure drop is considerably significant t hroughout the test range.