Design of axial flow compressors 1

[zingzang]

Can someone tell me what would be the minimum mass flow rate required to gain a pressure rise of 25 KPa in an axial flow compressor with an RPM of 3000. The inlet conditions being 1 atm and 373 K. The fluid used is steam with density of 0.59 kg/m3.

 

[rotw]

Typically 150 000 m3/h actual flow of air is something I have seen for axial; this figure is for ambiant air conditions at inlet, on hot site (40 degC) but spinning at much higher speed then yours.

since air MW=28 is about two times the MW=18 of water (very roughly) and if I keep mass flow constant, this would correspond 300 000 m3/h actual flow for the steam. You can calculate back the mass flow based on 40 degC and then lower it further to match your temperature.

Also to precise that my minimum is defined to be 'Minimum axial = maximum centrifugal'...

Remember I have made a comparison based on different speeds, so be carefull...

I think when flow is defined; 25kPa has more to do with adding more stages to the axial machine...
Except if you perform a precise calculation/sizing, procedure would be that by knowing number of stages and speed, you could define diameter or blade height at inlet and then minimum flow would follow.

My guess only....

"If you want to acquire a knowledge or skill, read a book and practice the skill".

 

[zingzang]

Thanks a lot rotw for your answer. I would be really grateful if you could suggest me some readings or references.

 

[zingzang]

Hi rotw, don't you think for constant mass flow rate the volumetric flow should change as the inverse ratio of density of two fluids rather than their molecular weight?