Dear All,

I have a problem on stress analysis of steam turbine piping(CAESAR II File Attached.
the allowable load on nozzle is higher, and i have done lot of trial & error with my model, but load on nozzle is still remains.

please suggest me possible way to reduce loads on turbine nozzle.

Some detail of line as follow.

Exhaust line size 8".
Temperature 380 C.
Pressure 1814 Kpa.

please reply me as soon as possible.



Regards,

Tom

Waiting for reply????????

Hi,
This is what I got, kindly let me know what is your allowable? are you referring to NEMA? Right now I dont have anything to compare as I am not in my office. Kindly give me the allowable values.

I just saw in your model that there are very few guide supports (in fact no guide) are provided, as turbine is a rotary equipment there are vibration, to avoid that you must give a proper supporting arrangement.

Here is what I got, Fx= 2.969 kN, Fy = 1.473 kN, Fz = 0.498 kN, Mx = 0.28kNm, My = 0.2192 kNm, Mz = 0.956kNm.

I have an doubt after looking in your Caesar-II model that, if you had done any analysis before? Anyway that's my personal comment.

Regards,
RK

Cruse,

You have at least three fundamental problems here in addition to your inexperience. Can you identify those problems ?

Thanks Mr. RK,

when ever i put guide in the line nearer to turbine nozzle, the force ie. Fx increases so that i am avoiding guide.
please provide guide at suitable position.

The allowable here is NEMA SM23,

how it is possible to reduce force in X direction and moment in Y direction.

I have supported elbows with two spring support( refer CAESAR II file).



The NEMA has different concept.
we have to check
1. Force as per 3F + M < 500*D.
where F and M is resultant Force a Moment.

2.Moment about resolution point.

3. Summation calculation.

I hereby attached NEMA calculation generated by Caesar-II for same model.
but now piping routing has been changed, and i m in problem.


As per you quick view and sharp understanding, i thing you have good experience in this field.

please suggest me how can i reduce the forces and moment.

Thanking You.


Cruse

Hi,

I am not aware about details what kind of turbine you have? But you should first understand what you are doing. Just providing a spring hangers or rest support will solve your problem (If you are lucky) but think practically also, will you allow your line without any guide?

One simple question: - Are you sure your C-II model is correct?

Regards,
RK

Dear RK.

I know it is not possible without Guide.
i have modified my model with guide.
Please make change so that load Fx and Moment in Mx is reduced.
after that load is about
Fx=2.8KN
Fy=-.872KN
Fz=0.506KN
Mx=-0.448
My=3.529
Mz=-0.48

I am attaching again my modified CII model.

I hope my model is correct.
The Steam turbine has 4" inlet and 8" Exhaust connection.

Please review my model.


Regards,
Cruse

I am still waiting for your reply!!!!!!!!!!!!!!

Regards,

Cruse

Hi,

I had not yet checked your attachment, I will check and come back to you.

Regards,
RK

Who is doing this analysis and who is getting paid for it ????

Dear Mr. MoverZ,
No one getting paid from this site, this is just a discussion forum.
i have a problem on my model thats why i m here, if u think you can resolve then resolve it else keep you knowledge within your bag.

Regards

Cruse.

add guides/stoppers

Cruse,

In the first instance, you should understand the problems associated with steam turbine and then attempt to do a stress calc. Get proper guidance from your seniors within the company.
The calc cannot be solved without knowing where the steel structures are, the type of steam turbine...and so on..

Stress analysis is not just solving the problem on paper...it should also work at site.

Get your basics right first..
I have looked into your model, I find a support at node 90..could you explain me what that support is doing...?? The support does not take any load...neither does it solve any purpose..

It looks like you have no experience in stress analysis and attempting to solve Steam Turbine calc.

Regards

Cruse,

There is one person getting paid to solve this problem, and that is you. Everyone else here gets paid by their respective companies to do work for their clients. Any help you get here comes from their interest in improving the field of stress engineering.

This forum is not a school to teach people how to be stress engineers. It is a forum for technical professionals to address issues related to the use of Caesar II and, in a broader sense, to trade experience in dealing with different types of stress problems.

You are not entitled to an answer to your questions. Further, you are most certainly not entitled to have anyone here solve your problem for you. While you may get pointers on approaches to take, you will be the one responsible for finding the solution that you are being paid for.

Your attitude in this thread has been wrong from the get go and you are not doing much to inspire any of the regulars here to want to help you. You also reflect poorly on your nation with your attitude. I work with many fine Indian engineers and I've never come across one as rude as you. Quite frankly, your next post on this site should start off with an apology.

In spite of this, I will offer these things for you to consider:

You will need to employ guides and anchors to isolate the turbine from the bulk of the piping system, directing the expansion away from the turbine. As you have it modeled, with no determined anchor, you leave the system to find it's own center and drive expansion as it will. This will not work in general, and will never work with load critical equipment.

You will also need to make routing changes to provide flexibility local to the turbine to reduce loads to acceptable levels. I would look at anchoring either node 140 or 170 and then proceed to make changes between the turbine and your anchor node to get the loads down where they need to be. With turbines, it is also often necessary to manually adjust the springs from Caesar's initial predictions in order to tune the load distribution to satisfy NEMA.

Cruse,

I tried to work on your system and it looks like the line is not at all flexible, that's the reason of excessive nozzle loads. Some important things I want to suggest you are,
1. Don't leave the last point unsupported.
2. Try to place an stop in the line and changed the pipe route, the fact is your pipe in running along same direction, try to give some flexibility by adding some more elbows.
3. I have found the solution but, I will prefer that you should work on the system yourself by considering all the points mention above as well as by the other engineer in their post.

Best of luck,

Note: - Edward is correct, you should be polite when asking some one. Please keep this in mind.

Regards,
RK

Dear Mr Cruse_tom

Can you please attach the piping isometric ( CAD or PDF). The line / subject looks interesting for learner guys like me.

Best regards

Venugopal

Dear All,

First of all i want to say sorry to RK, MoverZ, Supermo, SKK, Edward Klein and specialy to MoverZ earlier post and i am very apology for the same.

I was so stressed on that day, n it is happened due to lot of different pressure on me.

This kind of word you can not find in my future post.

Sorry MonerZ, it shameful for me. please forgive me for this.and unless or until u not reply this post, I will be filing said for this.

Please Forgive me my sweet dear MoverZ.

I am waiting for ur reply.


Cruse.

Dear venu,

plz find attached iso of steam line.
i have already attached CAESAR II file in earlier post.

regards,

Cruse

Dear Mr Cruse ,

Thanks for attaching the isos.Yes, I noticed that you have earlier attached CAESAR II file, but it is prepared on a higher version. The place where I learn Ceaser has an old 4.5 version. I feel interested to redo the model and observe the valuable inputs the learned fraternity have offered you.

While at it will be possible to save a file to a lower version in Ceaser , like we do in autocad. Can some one advise.

best regards

Venugopal

You cannot save a model to a lower version (this has been discussed many times). Data structures change and new items are introduced - you can't move down to an earlier version.

Thanks to you Mr Richard for the clarification. I am sorry that I posed a question which understandably had already been answeredearlier. I am trying to catch up with the old posts so as to avoid this kind of questions.

This forum is organized in a splendid way. Please accept my compliments.

Best regards

Venugopal