Discussion on the inlet and outlet areas of the heat exchanger shell and tube bundle

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Dear engineers, in section 6.8.1.2 on flow area of GB/T151 version 2014, the requirement that the inlet and outlet areas of the shell and tube bundle must be larger than the cross-sectional area of the pipe openings has been removed. Will you still take this factor into consideration when designing? Previously, it was always necessary to ensure that the inlet and outlet areas of the shell and the tube bundle met the requirement of being larger than the cross-sectional area of the pipe openings. I encountered this problem while working on a heat exchanger recently; the inner diameter of this heat exchanger is 700, the medium flowing in the shell side is gas (we usually install baffles when the medium is gas), the diameter of the material inlet pipe is DN300, and the length of the heat exchange tubes is 4500, with fixed tube sheets. The problem arises because, according to the previous standards, the position of the baffles would have to be very low, and the required Bs value (the spacing between baffles at the inlet or outlet) would be quite large. There are 12 baffles, with a spacing of 300 units (the number of baffles and their spacing cannot be adjusted). As a result, there isn’t enough space at the other end of the shell side to accommodate the outlet pipe (which also has a diameter of DN300). If this requirement isn’t taken into account, then none of these problems arise. Have you encountered this issue during your design work?