If \(\Delta h_m\) and \(\Delta h_f\) are the enthalpy drops in moving and fixed blades respectively, then the degree of reaction is defined as

Explanation:

• Axial flow compressors usually consist of a series of stages
• Each stage comprises of a row of rotor blades followed by a row of stator blades
• The working fluid is initially accelerated by the rotor blades and then decelerated in the stator passages
• In the stator, the kinetic energy transferred in the rotor is converted to static pressure
• This process is repeated in several stages to yield the necessary overall pressure ratio
• Degree of reaction provides a measure of the extent to which the rotor contributes to the overall pressure rise in the stage
• For all types of axial flow compressors, the degree of reaction is usually 0.5.

\({R_x} = \frac{{{\rm{Static\;enthalpy\;rise\;in\;the\;rotor}}}}{{{\rm{Stagnation\;enthalpy\;rise\;in\;the\;stage}}}}=\frac{\Delta h_m}{\Delta h_m+\Delta h_f}\)