Boost vs Temp vs Mass Flow

[Jerryl]

Was thinking ; Are there diminishing returns in mass flow as temp increases and at what PR/temp does this occur?

Goal:
Create graphical display of calculated mass flow vs charge temp at different PR with/without alcohol.

Disclaimer:
These are calculated numbers and may not correspond to your set-up.

Assumptions made:
Static: 231 CID @ 90% VE / Turbo Efficiency 65% / Baro 14.7 / RPM 5000 / 70F Ambient / No IC /

Definitions:
Boost (PSI) = At Compressor outlet
Temp (F) = Compressor outlet temp
Temp Alky (F) = Charge temp with alky injection based
Mass Flow = lbs /min

 

[BRAD_PADGETT]

With your knowledge and hands on experience please advise. What would you like me to log?

 

[Jerryl]

Hi Brad,
This was just a graphical representation of a model which I decided to share. The model is based on years of data collection and analysis.
No need to log anything, but thanks a lot!

 

[Nigel]

Jerryl, I assume you are using an idealized concept where normal design limits are not a constraint. As long as you maintain compressor efficiency, mass flow will continue to increase in a linear fashion. I don't think, with an internal combustion engine, you could reach a PR limit without hitting some other combustion, thermal, mechanical, or aerodynamic limit of the machinery. Gas Turbines use much higher PRs than we see, the limiting factor for them is blade design. Interesting question, did you have some other thoughts or information on the topic?

 

[Jerryl]

Jerryl, I assume you are using an idealized concept where normal design limits are not a constraint. As long as you maintain compressor efficiency, mass flow will continue to increase in a linear fashion.

I don't think, with an internal combustion engine, you could reach a PR limit without hitting some other combustion, thermal, mechanical, or aerodynamic limit of the machinery. Gas Turbines use much higher PRs than we see, the limiting factor for them is blade design.

Interesting question, did you have some other thoughts or information on the topic?

Yes, True, No, thanks!