Entrance-length dendritic plate heat exchangers

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© 2017 Elsevier Ltd. Here we explore the idea that the highest heat transfer rate between two fluids in a given volume is achieved when plate channel lengths are given by the thermal entrance length, i.e., when the thermal boundary layers meet at the exit of each channel. The overall design can be thought of an elemental construct of a dendritic heat exchanger, which consists of two tree-shaped streams arranged in cross flow. Every channel is as long as the thermal entrance length of the developing flow that resides in that channel. The results indicate that the overall design will change with the total volume and total number of channels. We found that the lengths of the surfaces swept in cross flow would have to decrease sizably as number of channels increases, while exhibiting mild decreases as total volume increases. The aspect ratio of each surface swept by fluid in cross flow should be approximately square, independent of total number of channels and volume. We also found that the minimum pumping power decreases sensibly as the total number of channels and the volume increase. The maximized heat transfer rate per unit volume increases sharply as the total volume decreases, in agreement with the natural evolution toward miniaturization in technology.






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Bejan, A, M Alalaimi, AS Sabau and S Lorente (2017). Entrance-length dendritic plate heat exchangers. International Journal of Heat and Mass Transfer. 10.1016/j.ijheatmasstransfer.2017.06.094 Retrieved from https://hdl.handle.net/10161/15197.

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Adrian Bejan

J.A. Jones Distinguished Professor of Mechanical Engineering

Professor Bejan was awarded the Benjamin Franklin Medal 2018 and the Humboldt Research Award 2019. His research covers engineering science and applied physics: thermodynamics, heat transfer, convection, design, and evolution in nature.

He is ranked among the top 0.01% of the most cited and impactful world scientists (and top 10 in Engineering world wide) in the 2019 citations impact database created by Stanford University’s John Ioannidis, in PLoS Biology.  He is the author of 30 books and 700 peer-referred articles. His h-index is 111 with 92,000 citations on Google Scholar. He received 18 honorary doctorates from universities in 11 countries.

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