Factors Influencing gas Turbine Performance


Thread Starter


To what degree do the following parameter affect or influence the Net Dependable Capacity (NDC MW output) of a typical gas turbine engine (say GE Frame 6): The ambient temperature, ambient pressure, ambient relative humidity, water injection rate, system frequency, power factor, voltage, fuel properties and gas turbine fired hours? How can I approximate or account for these factors to correct back the operational output at a given condition to performance basis condition of the machine? Is there a practical formula relating these factors?

Bob Johnston

What you are looking at is doing a Performance Test and relating everything back to ISO conditions. Somewhere in the data supplied with your equipment there should be a set of Performance Curves which allow you to correct output to Inlet Temp., Inlet Losses, Exhaust losses, humidity,altitude, etc. If you Google for "Turbine Performance Testing" you should get some info on how to perform the tests or if you want to drop me your Email address to [email protected] I think I have some documents that will give you some basic guidance
What Bob said - get your OEM contract documents and startup material, which should include the Performance Test Procedure and Correction Curves.

Rules of thumb for a large industrial frame gas turbine include:
* Output drops approximately 1% per 3F increase in compressor inlet temperature
* Output drops approximately 1% per 1% drop in ambient pressure

The rest are harder to quantify and will depend to some degree on the controls and emissions systems in place. If you can find your acceptance test procedure from the OEM, the curves should be in there.