Heat exchange tube deflection
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Is it still necessary to calculate deflection when the heat exchange tube is placed vertically? Should the issue of deflection be considered in all situations?
I’m really not sure about this; I’m looking forward to experts providing an answer!
I haven’t heard that deflection needs to be calculated; it probably isn’t necessary
No need; when it’s placed vertically, there’s no need to worry about deflection! You should know the reason for deflection, right?
Thank you. Actually, I think no calculations are needed when it’s placed vertically, but I’m not so sure when it’s placed horizontally, because GB151 specifies a maximum unsupported span; there might also be considerations related to deflection – otherwise why would there be restrictions on the spacing? Laying it horizontally creates the conditions for deflection
Thank you. Actually, I think no calculations are needed when it’s placed vertically, but I’m not so sure when it’s placed horizontally, because GB151 specifies a maximum unsupported span; there might also be considerations related to deflection – otherwise why would there be restrictions on the spacing? Laying it horizontally creates the conditions for deflection
Vertical placement can be ignored; horizontal placement needs to be considered, but the impact is minimal. Typical shell-and-tube heat exchangers or tubular evaporators include end plates, which are primarily used to enhance the turbulence of the heating or cooling medium and also serve to secure the tubes in place.
For vertical types, it seems that there’s no need to consider deflection, as deflection is probably caused by the pipes being too long and sagging naturally due to the lack of support; this problem does not exist in vertical setups, but it must be taken into account in horizontal ones.
GB151 does not address the issue of deflection in detail; only on page P74, in clause 5.9.6 regarding support plates, it is stated that \"when baffles are not required for the heat exchanger, but the unsupported span of the heat exchange tubes exceeds the values specified in Table 42, then support plates should be installed to support these tubes and prevent excessive deflection of them.\" ” Can it be understood that for vertically mounted structures, the condition for deflection generation is not taken into consideration; for horizontally mounted structures as well, deflection is not an issue as long as the unsupported span does not exceed the maximum value? Is this a proper way to understand it?
Both vertical and horizontal types exhibit deflection, so it should also be taken into consideration; it can just be omitted if necessary!
In a vertical position, deflection theoretically does not need to be considered. Deflection is defined as the linear displacement of the center of the cross-section along a line perpendicular to the axis when there is bending deformation; in other words, deflection is a measure of bending deformation, and since no bending deformation occurs in a vertical position, deflection can be ignored in that case. However, it needs to be taken into account in a horizontal position.
The senior up above analyzed it very logically. I would like to ask whether, in the case of vertical heat exchangers, it is not necessary to take into account clause 5.9.6 of P74 in GB151 regarding support plates: \"When the heat exchanger does not require baffle plates, but the unsupported span of the heat exchange tubes exceeds the values specified in Table 42, then support plates should be installed to support these tubes and prevent excessive deflection of them.\" ”
In fact, this issue cannot be addressed in a general manner; it depends on the perspective from which it is analyzed – theoretical research or practical engineering applications. Additionally, it’s important to consider the approximate size of the heat exchanger in question. Theoretically, margin of safety can be taken into account for any heat exchanger; in practice, however, many decisions are based on engineering experience. Whether margin of safety is necessary for a particular device is determined by various standards and guidelines that are also based on actual engineering experience. Therefore, discussing whether vertical heat exchangers require margin of safety has little practical significance.
The maximum unsupported span can be selected based on the values recommended in GB151; there is no need to calculate the deflection.