Swirl Angle Software for GE

A

Thread Starter

ABDI

hi,
I HAVE swirl angle software for GE FRAME 9E NON-DLN TYPE. can use this software for GE FRAME 9E DLN?

BECAUSE when going just to transfer mode, we have spread around 165 deg-c. Is related to the transfer nozzles.
 
ABDI,

You could certainly try. Troubleshooting with a swirl angle chart is always iffy at best. It's just a tool for estimating which combustor(s) might be experiencing a fuel flow problem or a combustion hardware problem--it's not an exact tool.

If you're only having the spread problem when transferring from Lean-Lean to Premix, then, yes, it could be the transfer nozzles/passages.
 
ABDI,

The transfer pipes and internal "holes" of the secondary fuel nozzles can be called "passages" because they pass gas (no pun intended).
 
CSA,

Why you say secondary fuel nozzles? we have spread just during transfer. we haven't any spread In primary ans lean lean mode.
 
ABDI,

Because, the transfer passages/nozzles are part of the secondary fuel nozzles.

If the DLN-I combustion system on the turbine at your site uses a Gas Transfer Valve, if you follow the fuel line from the Gas Transfer Valve to the manifold around the axial compressor casing and then from the flexible hoses from that manifold to the fuel nozzles, you will see that the transfer nozzles are integral to the secondary fuel nozzle.

When transferring from Lean-Lean to Premix, ALL of the fuel must flow into the secondary combustion zone. The only way that can happen is if the fuel flows through the secondary fuel nozzles. Some DLN-I combustion systems did NOT use Gas Transfer Valves and all of the fuel was "forced" through the secondary fuel nozzle passages and orifices. This causes a phenomenon known as "screech" during the combustion mode transfer and also increases the dynamic pressure pulsations in the combustors greatly. While it works, it's not really good for the combustion hardware.

So, GE and its packagers, went back to DLN-I systems with Gas Transfer Valves. The purpose of the gas transfer system is to have another set of nozzle orifices--on the secondary fuel nozzles--through which fuel can flow during the Lean-Lean to Premix combustion mode transfer. This reduces the dynamic pressure pulsations inside the combustors and is much easier on the combustion hardware. It does, however, increase the complexity of the DLN-I system--because it requires a gas transfer valve and hydraulic actuator and electro-hydraulic servo-valve and LVDTs, and purge valves and limit switches, and more piping and manifolds and flexible hoses.

Gas fuel only flows through the transfer nozzles and passages (and the gas transfer valve) during a Lean-Lean to Premix transfer. At all other times, the gas transfer valve is closed, and purge air (CPD) is flowing through the transfer manifold, transfer flexible hoses, and the transfer passages and nozzles--which are integral to the secondary fuel nozzles. Again, because during a Lean-Lean to Premix transfer ALL of the fuel has to flow into the secondary combustion zone--and the only way it can do that is through the secondary fuel nozzles, including the transfer passages and -nozzles of the secondary fuel nozzles.

Please have a look at the P&IDs for the Gas Fuel System (GE usually calls these drawings the "Schematic Piping" drawings--everyone else in the world calls them P&IDs). They should clearly show how fuel passes through the system. As an operator or technician or an owner or a manager of a power plant with a GE-design heavy duty gas turbine you should be very familiar with the P&Ids for the systems on the turbine.

And, if--as it seems--you are having DLN-I problems, you should really, at a minimum, be referring to the Gas Fuel and Fuel Purge P&IDs to become as knowledgeable as possible about the systems in use at your plant. They are not that difficult to understand, though, at first glance they may seem to be. There is usually another document provided with the drawings and parts lists which is called the "Piping Symbols" drawing which can be used to help understand the symbols on the drawings. But, I've seen people at other sites use the Internet to find out what the various symbols mean before they became aware of the other documentation available in the manuals provided with the turbine and auxiliaries.
 
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