TNGV: Speed/IGV temperature bias.

TNGV is in IGVXCHANNEL Module, and it is calculated by FX1,TN_ERR and other variables.

And it is only used once in the entire CSP. It is used as a bias in the calculation of CSRGV.

Why TNGV is calculated,and why it is used in the calculation of CSRGV.
Can someone explain it physically?

And I am also confused with the name of XCHANNEL.

Best regards!
neo
[email protected]

 

Neo,

I'd need to see the application code to make a reasonable comment; I've not seen TNGV before that I can recall.

I imagine that TNGV is used for some IGV control bias under extreme conditions--but that's just a SWAG (Scientific Wild-Arsed Guess).

As for XCHANNEL, well, requisition engineers are free to name their segments or sections whatever they want as there is no peer or supervisory review of such naming. And if Belfort was the originator of the application code, well, then no more need be said. Obfuscation and complication are their hallmarks--why make something simple when it can be obtuse and overly complicated, not to mention mysterious if an odd name can be chosen!

 

Neo,
I was very remiss for not telling you to check the Control Specification for information on this function. Usually, Sect. 06.nn.nn is for IGV control, and it's possible some cryptic description that we could use to develop a better understanding is in one of the sub-sections of Sect. 06.

Whenever you encounter a function like this, it's always a good idea to check the Control Specification for more details/information. Especially for algorithmic functions, not so much for logic/sequencing.

And, of course, since you are working on a Mark VIe there is the capability for Comments ("notes") in the application code.

As always, read everything written in sentences (complete or incomplete) in a GE manual or drawing or Toolbox/ToolboxST/CSP with a critical eye. In other words, don't read it literally--expecting what's being done exactly matches the written word. Instead, read any written descriptions for 'intent'--meaning that at some point the author thought it should work this way or that way, and realizing that someone else could have changed things later without correcting the written description.

Are we having fun yet?

 

As always, read everything written in sentences (complete or incomplete) in a GE manual or drawing or Toolbox/ToolboxST/CSP with a critical eye.

I find this comment in CSP:
Design standard BF5B_CAF_Coordinated Air Fuel Control.


I was very remiss for not telling you to check the Control Specification for information on this function. Usually, Sect. 06.nn.nn is for IGV control, and it's possible some cryptic description that we could use to develop a better understanding is in one of the sub-sections of Sect. 06.

I cannot find any information in Control Specification about TNGV.

(TNKCCGG*(1-FX1)+ TNKCCGL*FX1)*TN_ERR
TN_ERR: Speed error
FX1:Fraction of liquid fuel
TNKCCGG: CROSS CHANNEL GAIN FOR LIQUID FUEL 130
TNKCCGL: CROSS CHANNEL GAIN FOR GAS FUEL 80

According to the above formula, the TNGV is determined by Speed error and fraction of liquid fuel.

If it is a dual-fuel machine, TNGV will change significantly in the fuel transfer. As TNGV is used in CSRGVV3 block, it seems that it will change IGV angle, thus affecting the airflow.

Of course, it is fun to get a deeper understanding of CSP and reading your comment. Thanks again.

FX1: Fraction of liquid fuel
FX1=FSR1/FSR
Heat energy fraction of liquid fuel?

Best regards!
Neo