turbine corrected mass flow

[Gaz1]

have a question about turbine mass flow.

garrett give turbine maps for their turbos with 'corrected gas turbine flow' against 'pressure ratio'.

what exactly is the corrected mass flow. an equation for correcting the mass flow with temperature and pressure is given. but is it not the volume flow that depends on temp and pressure?

thanks, gareth.

 

[JayMaechtlen]

I'm not sure, but maybe one of the other forums here would be better than this one.
Aside from that, there is a DIY-Gas Turbines group on Yahoo with some sharp guys. They build gas turbines from (usually) turbochargers.
regards
Jay

Jay Maechtlen

 

[gtsim]

The performance of gas turbine components such as compressors and turbines are usually quoted in terms of non-dimensional parameters e.g. plotting pressure ratio VS non-dimensional flow (W?T/P).

where W is mass flow rate (kg/s), T is temperature in K and P is pressure in Bar-A.

This is done for a series of non-dimensional speeds (N/?T), where N is the speed in RPM.

Non-dimensional flows are in fact Mach numbers. Some OEMs prefer to quote the non-dimensional flows in terms of referred or corrected mass flow rate (kg/s). To do this we must refer the mass flow rate to a reference temperature and pressure – usually 288K and 1.013Bar. Now the referred or corrected flow becomes W??/? whose units are kg/s. ?=T/288 and ?=P/1.013. Similarly the referred or correct speed is N/?? and the units are RPM.

Regards

 

[hydrae]

I thought 'corrected' was to add in the mass value of the fuel, it enters as a liquid in the compressor for gasoline or injected at TDC on diesel and exits as a gas as a product of combustion
Hydrae

 

[gtsim]

I am not too familiar with spark ignition and compression ignition engines and you could be right on what you say. But in gas turbines, we need to correct or refer the engine performance to a standard temperature and pressure. This enables us to compare the performance of different gas turbines on an equal basis (i.e. compare apples with apples). This is achieved using the identities described above.

Regards