The calculation of heat exchanger wall temperature and its applications
Thread Content
(1) Issue: The wall temperature of the heat exchanger shell (wall) is often essential data for stress calculations. For example, if expansion joints are to be installed on the shell of a fixed-tube-sheet heat exchanger, the wall temperature is required for the calculation of those expansion joints. (2) Calculation: The wall temperature is the combined effect of heat exchange within the entire heat exchanger and heat exchange with the environment. Therefore, to calculate the wall temperature, it is necessary to account not only for the heat transfer between the two cold and hot fluids but also for the heat transfer with the surroundings (taking into account the insulation layer and the ambient temperature). Therefore, the wall temperature can be calculated correctly only after comprehensively calculating the heat transfer of the heat exchanger. It seems that only software capable of performing a complete calculation of the heat exchanger can accurately determine the wall temperature. (3) Some software cannot calculate wall temperature; among those that do calculate it, the calculations are quite crude, as they fail to perform a comprehensive calculation of heat transfer.
I see, I was looking everywhere for software to calculate wall temperature; now I understand
What model does Heat Exchanger Master use? Go ahead, tell me
1. There are too many models. A complete heat exchanger calculation software does not rely on hundreds of formulas, as it needs to handle various aspects of heat transfer, fluid dynamics, heat balance, and structural design calculations ； 2. Some models are unlikely to be used through manual calculation; therefore, manuals and textbooks that start with manual calculation do not include these complex models. For example, the system of differential equations describing the heat balance in the tube side, shell side, and environment—you won’t find this in university textbooks or design manuals, because it isn’t suitable for manual calculation ； In short: true software is by no means a programming of manual calculation methods—it uses models that are themselves more complex, comprehensive, and accurate than those used in manual calculations.
Generally, the wall temperature is calculated for the purpose of strength design. . . We all use the average temperature difference; it’s a conservative approach, but it’s relatively safe
Are there any examples for calculating wall temperature? Based on an example of actual design? A general formula with few parameters and accurate calculations? ?
Good topic; I’d also like to know how to determine the wall temperatures on the inner and outer surfaces of the heat exchange tubes.