The issue of the baffle notch direction in HTRI

Thread Content

As a beginner in heat exchanger calculations, I encountered a point that is easy to confuse, so I’ve written this down as a note. If any of you know something that’s incorrect, please let me know. Using the HTRI calculation formulas and the program for selecting baffle types, the calculation result shows “parallel”. By checking HTRI’s definition of baffle cuts: Baffle orientation refers to the orientation of the baffle cut relative to the inlet nozzle centerline, with the result printed as PARALLEL or PERPENDCLAR (when the baffle cut is perpendicular to the nozzle centerline). By also looking at the direction indicated by the graph related to the baffles in the results, it turns out that it actually corresponds to what we generally consider to be the vertical type. Therefore, regarding the definition of the baffle notch direction in HTRI, it is necessary to consider the specific circumstances; one cannot simply fill it in according to the description provided in the HTRI results. In addition, GB/T 151 provides a clear definition: 6.8.2.4 When the shell side of a horizontal heat exchanger contains a single-phase clean fluid, the gaps in the baffle plates should be arranged horizontally. If the gas contains a small amount of liquid, then a liquid inlet should be provided at the lowest point of those baffle plates whose gaps face upward. If the liquid contains a small amount of gas, then a gas inlet should be provided at the highest point of those baffle plates whose gaps face downward ； In horizontal heat exchangers, condensers, and reboilers, where the fluid in the shell side is gas, or where a liquid phase coexists with solids in the liquid, the gaps in the baffle plates should be arranged vertically left and right, and a liquid inlet should be provided at the lowest point of the baffle plates.