Heat rate improvement after replacement of compressor rotor and HGP components

I need to quantify performance improvement in a Gas turbine (Frame 9) for replacement of 1) Compressor rotor and 2) HGP components separately. A pre shutdown performance test of the GT was carried out after an offline water wash and data were recorded. Similarly, post overhaul test is conducted and data is recorded, but the OEM is not providing separate quantification of performance improvement, mainly in heat rate due to rotor replacement and HGP componenent replacement. We had entered into a performance guarantee from OEM for HGP component replacement and would like to assess performance improvement exclusively due to replacement of HGP components.
Can experts suggest methods which can be employed for such case? Thanks !

You--and the OEM--are bound by the terms of the contract. There's nothing we can do to get the information you feel you are due. You, and possibly your the lawyers which represent your Company are going to have to review the Contact which you signed with the OEM and see what they are required to provide you.

If you didn't get the data which was collected by the OEM during their testing and they are not sharing the information with you now, there's not too much you can do to replicate any testing which has already been done.

I see this kind of complaint too often. Contract wording has to be reviewed by several knowledgeable people, possibly but usually including lawyers, to make sure there are clear deliverables and clear remedies.

My suggestion at this point (and probably about the only thing which can be done at this point) is to withhold any further payment until the test data and test results have been provided to you and your representatives for review. That will get their attention, and if there isn't proper wording in the contract and you have to make payment without getting what you feel you are due, then you will just have to consider this as a very difficult lesson and learn from it and don't make the same mistake in the future.

I wish the news was better, but without being able to see the contract that's about all that can be said. If you're not familiar with performance testing and analysis you need to start researching the subjects and get as educated as you can be so that in the future you will be prepared for a similar situation. You need data and you need to agree on the data and the methods used to gather the data BEFORE the tests begin--or you are at the mercy of the supplier/provider.
Thanks for reply. While we will surely looking at contractual provisions, I wished to know if there are correlations for estimating power output based on change in total exhaust mass flow to turbine due to improved efficiency of a compressor post rotor replacememt. I have the data on compressor inlet/outlet conditions and fuel flow for pre/ post rotor replacement. Hence based on increased mass flow to turbine, how to assess increase in power. Once I have estimated this, balance improvemt can be attributed to HGP component replacement. Experts may please share.

When I hear heat rate used in relation to a power (electrical) plant I think of the relation of energy input (in Btu) to energy output (kilowatthour). When I hear exhaust mass flow (-rate) in relation to a gas turbine I think of exhaust heat and flow into an HRSG from the gas turbine exhaust. Sometimes, OEMs make guarantees on both--heat rate and exhaust mass flow (-rate). And, yes, gas turbines are essentially mass flow-rate machines--increase the mass flow-rate of air through the axial compressor, and hence the turbine section also, and the power output of the turbine (usually driving a synchronous generator to produce electricity--kW-Hrs).

In my experience, GT OEMs are very reluctant to share information about axial compressor efficiency and mass flow-rates. And because axial compressors are very unique machines, quite unlike many other similar types of compressors, estimating flows and efficiency is very, very complicated. And, because in most gas turbines today the most limiting factor for power production is axial compressor air flow most OEMs are loathe to discuss axial compressor efficiency or provide detailed information--because that is so important to their research and development and power output guarantee, including efficiency (again, primarily electrical power output, but in some applications, exhaust heat flow-rates as well).

[In decades past the limiting factor was mostly the heat that the hot gas path components could withstand (turbine nozzles and buckets (blades) and exhaust components). That's changed with metals technology; now, the metals can withstand much more heat meaning more fuel can be burned but the axial compressor designs have to be improved to allow more air flow to the combustors and turbine sections. Personally, I never thought I'd see this change--but it's happening. Look at some of the upgrades OEMs are selling now--completely new axial compressor casings and multiple stages of variable stator vanes, very much like aircraft engines use. And this has allowed higher firing temperatures which means more fuel--in addition to more air--which means higher mass flow-rates through the gas turbine and exhaust which means ever higher and higher efficiencies (heat rate improvements) and machine outputs. It's been impressive to watch the changes--due to technology improvements, and the sharing of technology between different types of gas turbine designers (heavy duty and aircraft turbines). And, of course 3D printing technology, too, as well as metallurgy improvements.]

I have seen some estimates in various texts and reference books which try to quantify axial compressor efficiency, but most seem to be very theoretical and can't really be used to define and definitively quantify the efficiency of any one axial compressor, just the "family" of axial compressors in general. Useful when designing HRSGs, but not so useful when trying to quantify GT output (electrical power output) as a function of axial compressor through-put and efficiency. There are just SO many variables and intangibles to be considered.

Being more of a practical, hands-on technician and not an ivory-tower or university clock-tower engineer I can gather performance data as required by the engineers and their computers to calculate (estimate, really, in my personal opinion) but I'm not one to make the calculations or explain the results. My apologies if I misunderstood your situation. Best of luck in your endeavour.