WRC297 addresses four issues in local stress calculation
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This post was last edited by “One Table of Sweet and Sour Pork” on June 16, 2017, at 13:48. At the request of the client, each process nozzle was checked under the external loads provided by the client, using the WRC297 method. During this process, two problems arose; I would greatly appreciate it if any experts passing by could help me resolve them! 1. The calculation requires that the distance L from the connection center to the tangent of the adjacent head be ≥ 2(DmT)1/2. However, if the distance specified by the process engineering team is slightly less than this value, should the connection position be adjusted in consultation with the piping engineering team, or can this effect be ignored? 2. A prompt will be given if the stress check is successful. Note: WRC297 recommends that the minimum outer diameter of the reinforcement ring be 1799.9 mm; the outer diameter of the reinforcement ring obtained through calculations for an open-type reinforcement is 1250 mm. Is it necessary to adjust it to the required value? 3. A prompt will be given if the stress check is successful. Note: According to W297 requirements, the minimum protrusion length of the section with a thickness of 18.0 mm at the junction between the fitting and the shell should be >=203.2 mm; the actual protrusion height of the fitting is 150+. Is it necessary to adjust it to this value? 4. 297 is not applicable to protruding nozzles; what is the effect of nozzle protrusion on the stresses in the cylinder and the nozzle? Is it conservative or reckless to calculate the inward extension as being level?
@zkbest, please help answer this. Thank you
Conditions 2 and 3 need to be met; try not to use WRC297. If it’s not mandatory, use WRC107 for the connectors as circular attachments
The error of WRC297 is relatively large; it becomes particularly dangerous when the ratio of the opening diameter to the cylinder diameter is high. It is better to use local stress analysis instead. As for the software, all the required conditions must be met.
Few heat exchangers can meet the requirements of the first criterion, whether it’s 107 297 or not
An inward extension ratio provides better stress resistance compared to a flush or inserted design, right?
The analytical design method in perforated reinforcement yields better internal stress conditions; finite element analysis confirms this. The local load has not been calculated; I don’t dare to guess
Sorry, I just saw it; I’m not sure if it’s too late to reply now. 1. The calculation requires that the distance L from the connection center to the tangent of the adjacent head be ≥ 2(DmT)1/2. However, if the distance specified by the process engineering team is slightly less than this value, should the connection position be adjusted in consultation with the piping engineering team, or can this effect be ignored? If it is slightly smaller, the impact should be minimal; the main consideration is the stress attenuation zone at the opening site – a value of 1/2 of the normal (DmT) level should suffice, and it’s best to avoid values that are lower than this. 2. A prompt will be given if the stress check is successful. Note: WRC297 recommends that the minimum outer diameter of the reinforcement ring be 1799.9 mm; the outer diameter of the reinforcement ring obtained through calculations for an open-type reinforcement is 1250 mm. Is it necessary to adjust it to the required value? I’m not sure how this recommendation is derived, or what software is used; is it also a 2(DmT)1/2 dimension? It actually comes down to stress attenuation – the reinforcement ring should be as large as possible. 3. A prompt will be given if the stress check is successful. Note: According to W297 requirements, the minimum protrusion length of the section with a thickness of 18.0 mm at the junction between the fitting and the shell should be >=203.2 mm; the actual protrusion height of the fitting is 150+. Is it necessary to adjust it to this value? It is also due to the influence of the stress attenuation range: is it the entire 150+ length, or are there pipes or flanges connected to it as well? Under normal circumstances, the impact should not be significant. If the length requirement cannot be met, the thickness of the connecting pipe can be increased appropriately. 4. 297 is not applicable to protruding nozzles; what is the effect of nozzle protrusion on the stresses in the cylinder and the nozzle? Is it conservative or reckless to calculate the inward extension as being level? Inward extension generally reduces the stress at the opening, so calculating it as if it were flush is on the conservative side.
This post was last edited by yuun on 2017-9-7 23:05. 1. The calculation requires that the distance from the connection point to the tangent line of the adjacent end cap be L≥2(DmT)1/2; however, if the distance specified by the process engineering team is slightly less than this value, should we communicate with the piping engineering team to adjust the location of the connection, or can this difference be ignored? If the end is a device flange or head, it provides reinforcement for the pipe joint, resulting in lower stress levels. It is a more conservative approach. 2. A prompt will be given if the stress check is successful. Note: WRC297 recommends that the minimum outer diameter of the reinforcement ring be 1799.9 mm; the outer diameter of the reinforcement ring obtained through calculations for an open-type reinforcement is 1250 mm. Is it necessary to adjust it to the required value? In this case, after the calculation is completed, use the WRC107 module to check whether the diameter of 1250 is acceptable; if it is acceptable, there is no need to increase the diameter of the reinforcement ring. If it is not acceptable, increase the diameter accordingly until it becomes acceptable. Additionally, the calculation for WRC297 is based on 1799.9. 3. A prompt will be given if the stress check is successful. Note: According to W297 requirements, the minimum protrusion length of the section with a thickness of 18.0 mm at the junction between the fitting and the shell should be >=203.2 mm; the actual protrusion height of the fitting is 150+. Is it necessary to adjust it to this value? Generally, there is no need for it; the fitting will not disappear just like that, and flanges are definitely available in the vicinity, which has a positive effect on the fitting. Or the pipe connected to it has a length that meets the requirements. 4. 297 is not applicable to protruding nozzles; what is the effect of nozzle protrusion on the stresses in the cylinder and the nozzle? Is it conservative or reckless to calculate the inward extension as being level? Choosing non-protrusion over protrusion is definitely a conservative approach. http://vcad.blog.163.com/blog/static/2157050802016117104255776/
Indeed, after asking the question I forgot to come back and check; when it exceeds the WRC calculation method, Nozzlepro can be used for calculation