Gas Turbine Inlet - Turbine Inlet Temperature

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ABDELAALI

Good evening,

I hope you are healthy. I want to ask you a question about the gas turbine, exactly on the reference temperature (inlet temperature to the turbine). how to calculate this temperature and what parameters control the evolution of this temperature?

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I don't know what model of machine you have, but GE machines always has 1 or 2 Thermocouples tagged CTIF (Compressor Temp. Inlet Flange). What you want to measure is the temp. just at the Inlet Bell Mouth as near to the compressor 1st. stage as possible. To calculate this from ambient Temp is difficult and inaccurate as it depends on inlet duct length, configuration, location, etc.
 
I read this differently.... And, the use of terms by the original poster was inconsistent, which doesn't help.

<i>Turbine</i> inlet temperature--sometimes called "firing temperature"--and approximated on GE-design heavy duty gas turbine control systems using the Combustion Reference Temperature calculation is the temperature of the hot gases entering the first stage turbine nozzles; it is a number that is somewhat magical and mythical. (GE calls the combustion reference temperature either TTRF or TTRF1--and it is just a calculation, that is used for determining when to switch combustion modes.) I would have to believe all heavy duty combustion turbines try to control the temperature of the gases entering the first stage turbine nozzles because if the temperature is too high then the turbine nozzles and/or buckets won't last as long as expected, and if it's too low then the power output from the unit won't be as high as expected.

"Firing temperature" is usually not measured--mostly because it's very difficult to get an accurate measurement using previous technology (pyrometers, mostly). Nowadays there are lasers and other types of technology that can be used to monitor the actual first stage turbine nozzle inlet temperature, but I don't think many machines have this equipment installed yet.

The calculation of the "firing temperature" is usually considered proprietary by the turbine manufacturer, but if you have a GE-design heavy duty gas turbine control system you can see the inputs to the combustion reference temperature calculation--usually compressor discharge pressure, axial compressor discharge temperature, axial compressor inlet temperature, etc. What actually goes on inside the "block" (algorithm) where the inputs are used to derive the combustion reference temperature (the calculated approximation of the hot gas temperature entering the first stage turbine nozzles) is hidden, and, again, usually considered proprietary.

Don't know if that's the information you were looking for, and probably not the detail you might have wanted, but the post wasn't really clear.
 
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