Calculating mean radius of a gas turbine rotor (blade and hub)

[jcm0889]

Homework Statement

I'm having difficulty obtaining an accurate value possibly due to unit conversions.

Homework Equations

r_m=mdot/(2*pi*U*N)
r_m=mean radius, ft
mdot=mass flow rate, lbm/s
U= blade velocity, ft/s
N= RPM

The Attempt at a Solution

I know that I have to convert Rpm into seconds and pi converts it 2 rads

 

[tiny-tim]

hi jcm0889! welcome to pf!

(have a pi: π and try using the X₂ tag just above the Reply box )

I know that I have to convert Rpm into seconds and pi converts it 2 rads

did you mean that?

2π converts R to radians

if that doesn't sort it out, show us your full calculations, and then we'll see what went wrong, and we'll know how to help!