Thanks very much dear Hidouri . Really it's a good document.

I can not find the attached file Khaoula Hidouri ???

The design of shell and tube heat exchanger using Kern method has the following advantages:

-Giving reasonably satisfactory prediction of the heat-transfer coefficient for standard design

-Simple to apply

-Accurate enough for preliminary design calculations

-Accurate enough for designs when uncertainty in other design parameter is such that the use of more elaborate method is not justified

Dear Heydar.

Thank you very much for your useful answer.

Kind Regards

I don't think you should confude the Kern method with NTU or LMTD methods, as the Kern method is a systematic approach/procedure to heat exchanger calculations, and is used in conjunction with LMTD (or NTU). The Kern method is obsolete nowadays, particularly due to the poor prediction accuracy of the shellside heat transfer coefficient and pressure drop. The shellside calculation method was superseeded in the 1960s by the more accurate Bell-Delaware method, and nowadays some variant of the flow-stream method originally presented by Tinker is used (see e.g. The Flow Stream Analysis Method by Wills and Johnston, 1984). The prediction accuracy is vastly improved relative to the Kern method.

Dear Erling. The difference between three methods is knowen well. However I want to understand how Kern method help in heat exchanger design. I'm thankful for your great answer and your explaination in this subject.

Kind Regards

I think that Kern method considers sizing parameters in effective way more than the others such as the ability to manipulate the pipe diameter and length, the tubes arrangement, the shell diameter, with correlations more accurate.

Thanks a lot dear Ammar for useful answer