Design of shell-and-tube heat exchangers without heat exchange tubes in the baffle windows

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This post was last edited by jiangyujy on 2010-4-13 22:47. Recently, I need to carry out a scale-up design for a non-standard heat exchanger; since it’s not possible to use software for the calculations, I had to do them manually using Excel. The baffle openings of this heat exchanger do not contain heat exchange tubes; in other words, the flow streams in the shell side and the tube side are always in cross-flow relationship, with no co-current or counter-current flow. A relatively simple method for calculating the shell-side convective heat transfer coefficient is the Kern method, but this approach can only be applied to ordinary heat exchangers with heat exchange tubes in the baffle windows. I first tried using the Kern method, but found that the results were clearly not realistic. I searched for many design manuals, and many of them covered the Bell-Delaware method. This method is much more complex than the Kern method; first, one must understand the 6 different flow paths in the heat exchanger in order to comprehend this calculation approach. The deviation between the actual convective heat transfer coefficient in the shell side and the ideal convective heat transfer coefficient is the result of the combined effects of the deviations caused by these different flow paths. Although the calculation involves over a dozen steps, which is rather tedious, the result is good, so all this effort is worth it. In my opinion, the book \"Heat Exchanger Design Handbook\" (published by Sinopec Press, written by T. Kuppan and translated by some domestic experts) provides the clearest explanation of this method; it makes it easy to understand how to calculate various parameters for different types of shell-and-tube heat exchangers in order to obtain accurate results. However, this book contains many printing errors, so it is best to consult it alongside the \"Chemical Process Design Manual\" (published by Chemical Industry Press, Sinopec Shanghai Engineering Company); compare some of the formulas with those in that book before using them. The “Chemical Process Design Manual” is printed quite accurately, but the explanations are not very clear, making it difficult to apply the knowledge to similar situations. Here, I would like to briefly summarize some of the insights I gained from this design, in the hope that it will be helpful to my friends at Haichuan.