Control.com - Nerds in Control

What is Thermocouple "position error" in exhaust gas temperature measurement?

Please advise

Never heard of this one.

Can you provide more information? What kind of turbine?

What kind of control system?

When did this problem start?

How long has this problem existed?

Hi CSA,

This is a control constant setting in the Exhaust spread true maximum calculation of a Aero engine used for O&G applications.

Upon investigation, i understood that "the angle difference between Thermocouple in the exhaust and swirl angle of Gas exiting the turbine causes a temperature measurement error " to offset that error they are adding up around 30 Deg C.

I trust that it could cause but not sure about what is the rational behind 30 Deg C.

Appreciate your advise . Thanks

4_20 mA,

I have absolutely zero experience with this concept.

I do have some experience with aero-derivative gas turbines, but this seems very unusual to me. I don't understand how swirl angle can be related to a measurement differential since even if the temperature of the exhaust at some point does not correspond to the temperature of the point at which the hot gases are entering the turbine nozzles (of either the gas generator or the power turbine)--which is what swirl angle is all about.

Now, there may be some aspect of how temperature is measured in a particular aero-derivative unit driving some kind of power turbine, but I would think that would be peculiar to the application and/or the type of power turbine, but still--not dependent on swirl angle.

But, I've been wrong before, and will be wrong many times again in the future (maybe even today!).

I have some qualms about the reasoning being stated for applying this "bias" to the exhaust temperature. Many times, the names and descriptions used in GE Speedtronic turbine control systems are not very accurate or descriptive.

Unfortunately, I can't be of any assistance with this concept. Perhaps someone with more experience with different aero-derivative applications might be able to help. If you could be more specific about the particular aero-derivative unit perhaps you might receive a more concise reply.

Hi CSA, Thanks

Can you be more specific? Are you referring to the TC temperature correction coefficient TTKXCOEF?

> Can you be more specific? Are you referring to the TC temperature
> correction coefficient TTKXCOEF?

Hi This is not GE turbine, this is RR turbines.