Fuel Nozzle Coking

[FieldTeam]

Does anyone have experience with fuel nozzle coking? If so, what were the causes, contributing factors and solutions concerning your particular situation? Specifics of my problem are GTCP331 running JP8. Primary and secondary incorporated into same nozzle assy. Bleed extraction used. Low operating time during use. Discrepancy starts with APU running 100% no load then shuts down when bleed air turned on. R2 of nozzle solves problem.
Thanks.

 

[icrman]

I'm not a turbine guy. But any kind of coking is generally caused by high operating temperature. And of course you have to have something there to coke. I am guessing it is coking internally? And not just a port thing. You may need to examine the temps, and the fuel flow rates, and pressures. ie fuel curves for that engine.

 

[ornerynorsk]

Don't know if there is similarity, but on fuel oil burners, any kind of incomplete combustion residue tends to be a catalyst for further build-up. Good Luck!

 

[btrueblood]

High sulfur content in the fuel will tend to drive coking.

 

[FranAle]

I have some experience in TPE331 gas turbine engine.Coking is feature present in some fuels, but you should check the materials´s bearing aft the turbine stage, some are ceramics, it means you should examine the oil quality and of course check the inspection intervals.

FranAle

 

[plasgears]

At GE on the B-1 engine we used pre-swirl vaporization before entering the comb chamber. In the hot zone fuel passages were large, and the flow divider valves were outside in a relatively cool zone.