Hello,

I´m now modelling tubing and I´m using B31.3 code. It´s for TG control hydraulic oil system.

It´s tubing of 1/4" with more than 700ºC so I understand that a flexibility calculation is necessary.

Does this system usually need formal calculation?

What´s the normal way to proceed with this kind of systems?

Thanks!

ask the vendor(honestly)

jhero,

It is a bit difficult to believe the tubing temperature 700 deg C with the hydraulic oil. Are you sure about that? What is the equipment to be lubricated?

Ibrahim Demir

jhero,

I may have misunderstood your question. Can you please give some more details where the hydraulic oil will be and the relationship with the temperature?
Where the tubing will be and how long. A sketch might be helpful.

Ibrahim Demir

Hello Ibrahim,

you are right, I have mixed different systems in which I´m working.

The tubing with 700ºC is for performance monitoring system, for pressure probes, and fluid is turbin gas.

I have more than 20 meters between the GT EXHAUST and GT EXHAUST DUCT PRESSURE SWITCH PACKAGE.

My doubt is about how to model SW Tee-s, like a rigid?

Should I study tubing like a usual pipe system?

Thanks!

jhero,

Normally we do not analyse this diameter of tubing with stress analysis programs. However, you are the one to decide because you have the full knowledge of the system.

I guess the pressure monitoring should be done at the source and tranfer measured data by the transmitters. This is the main problem you need to solve. If you are trying to get the gas samples for monitoring purposes you still need to provide a heat exchanger to cool the gas down in a short distance.

Kind regards,

Ibrahim Demir

I would not do the calculation using CAESAR II. I think there is a simple practical issue. If you would do the model and be happy site will practically always erect the line in a different way. I would think you have space and the cost of the tubing is not that high. Considering this I would draw erection procedure, which gives typical lay-out, support points and similar. Make the spec so that the line becomes flexible in all cases.

If it's SS tubing you will probably use material 352 and just turn off the nominal OD and put in the tubing OD in inches and the wall thickness.
E.G. 3" tubing has OD = 3" and .065" wall thickness.