The degree of reaction is given by:

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SJVN ET Mechanical 2019 Official Paper

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\(\frac{\text{Actual enthalpy change in rotor}}{\text{Actual enthalpy change in stator}}\)
\(\frac{\text{Actual enthalpy change in rotor}}{\text{Actual enthalpy change in stage}}\)
\(\frac{\text{Actual enthalpy change in stage}}{\text{Actual enthalpy change in rotor}}\)
\(\frac{\text{Actual enthalpy change in stator}}{\text{Actual enthalpy change in rotor}}\)

Answer 1

Explanation:

The Degree of Reaction

The degree of reaction is a critical parameter in the analysis of turbines and compressors. It quantifies the distribution of energy conversion between the rotor and the stator within a stage of a turbo-machine. Specifically, it is defined as the ratio of the enthalpy drop in the rotor to the total enthalpy drop in the stage (which includes both the rotor and the stator).

Mathematical Expression: The degree of reaction (R) is mathematically given as:

R = (Actual enthalpy change in rotor) / (Actual enthalpy change in stage)

Where:

Actual enthalpy change in rotor: Represents the energy transformation occurring in the rotating blades of the turbine or compressor.
Actual enthalpy change in stage: Represents the total energy transformation in the entire stage, which includes contributions from both the rotor and the stator.

The degree of reaction also provides insights into the distribution of pressure and velocity changes within a stage. For instance:

If R = 0, the entire enthalpy change occurs in the stator.
If R = 1, the entire enthalpy change occurs in the rotor.
If R = 0.5, the enthalpy change is equally distributed between the rotor and the stator (commonly referred to as a 50% reaction stage).