Compressor Example (cont'd.)
In order to determine the average stage pressure ratio, a variety of parameters are needed. Many we have already found in this example problem.
T1 represents the temperature of the fluid before the rotor and T1.5 is the temperature of the fluid after the rotor. Since the inlet velocity and temperature are both given, T1 can be found. T1.5 is not as easy to calculate as it depends on the work of the compressor which must be found first.
Here, m is equal to the mass flow rate, T is equal to the torque of the shaft for the compressor, and omega is the rotational speed of the rotor blades. Power is equal to the rotational speed * torque of the shaft.
The work done by the compressor must now be found as it is the power divided by the mass flow rate of the fluid.
Now that the work of the compressor is known, the temperature of the fluid after the rotor can be calculated. Then, finally, the average stage pressure ratio can be found.
CONGRATULATIONS!!! You have just designed a compressor.