Plotting system resistance onto turbo compressor map

[CWitkowski]

Hello,

I've cross posted this on another forum, but I suspect I may have more success here.

Basically I'm wanting to plot a set of system resistance curves (for a group of CAC's [charge air coolers]) onto a turbocharger compressor map.

I have a set of pressure drop curves for my CAC's, showing pressure drop (mbar) against mass flow (kg/min). I want to plot these onto my turbocharger compressor map, to give me a set of system resistance curves.

I can convert the mass flows into the correct volumetric flow units required by the compressor map (x-axis), but I'm unsure how to convert the pressure drop units into a pressure ratio (required by the y-axis on the compressor map).

Do I need to divide intercooler inlet pressure by outlet pressure (giving me a pressure ratio) and plot that on the compressor map? If I do this, the CAC PR values seem too low, ranging from 1 to 1.4, which when plotted are basically off the bottom of the map. Am I missing something? Do I need to calculate the CAC outlet pressure relative to ambient?

Any help would be much appreciated. I can find some similar(ish) information relating to centrifugal water pumps, but I'm not sure how to proceed with this case.

Regards,

 

[BigInch]

No cross-posting please.
It wastes a lot of time.

This question really should be in the gas compression forum.

See original post here,
thread71-239919

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/