Issues regarding the heat transfer coefficient and Reynolds number in the shell side of shell-and-tube heat exchangers
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I’m very confused. Some books state that the heat transfer coefficient for the shell side (referred to as the film coefficient in some books) can be calculated using the equivalent diameter of the shell side instead of do, along with the turbulent flow formula applicable to the tube side; however, this approach results in an excessively high Reynolds number. I would appreciate some guidance on heat exchanger design – which calculation formula do you use?
Different books use different names for it, but the meaning is the same; whether it’s the heat transfer coefficient for the shell side, the film coefficient for the shell side, or the heat transfer rate coefficient, it all refers to the heat transfer coefficient of either the shell side or the tube side, and this value is used in the calculation of the overall heat transfer coefficient. I’m not quite sure what you mean by using the \"equivalent diameter of the shell side instead of di, and applying the turbulent flow formula inside the tube to calculate the heat transfer coefficient\"; however, for calculating the heat transfer coefficient (heat transfer rate coefficient), di refers to the inner diameter of the tube on the tube side, while do refers to the outer diameter of the tube on the shell side.
I found that the formulas, algorithms, symbols, and names vary in different sets of books; the second and third editions of the Chemical Process Handbook also differ. In any case, once you understand the principles, it’s sufficient to read one book.
Most of these reference books are translated versions; they only convey the literal meaning, but the essence is the same: the heat transfer film coefficient ai/ao. The methods used to calculate the overall heat transfer coefficient are also identical, oh! ?
Calculate using the heat transfer coefficient inside the tube and the heat transfer coefficient outside the tube; the concept is clear and the overall approach to calculation is good
The most crucial aspect in heat exchanger design is determining the overall heat transfer coefficient; generally, empirical values or average values from the same industry are used as references. Additionally, if there are specific requirements regarding the temperature difference, special attention must be paid to the selection of the heat transfer temperature difference
How is Re calculated in the shell side? Is it using the outer diameter do of the heat exchange tubes?