:surprisedDegree of reaction is the ratio of static enthalpy drop across the turbine nozzle to the drop across the turbine. That being said, a hydraulic turbine is a reaction turbine with no nozzle drop so its degree of reaction would be 0. A gas turbine engine will vary depending on the drops. A degree of reaction of 50% means there is an equal drop across the nozzle as the turbine. Usually losses increase greatly after a R=1, so in that aspect a R<1 is more optimal. However, that is simply looking at the R value and no other design criteria.
That was just an analogy. Head is also a form of energy.I honestly can't comment on your use of head in stead of enthalpy for the DoR calculation.
This gives DoR of an impulse turbine as 1. All the enthalpy drop is in the nozzle.Degree of reaction is the ratio of static enthalpy drop across the turbine nozzle to the drop across the turbine
the ratio of enthalpy drop in rotor blades to the enthalpy drop in one stage(rotor + stator)
Going by your definition, it is apparent(assuming turbine means rotor). But that definition also give DoR of an impulse turbine as 1.As a note, you are not limited to a DoR between 0 and 1. It is simply a ratio so to get one larger than one, you simply need the stage's higher percentage of the enthalpy drop to happen across the rotor.
http://www.tfd.chalmers.se/~ulfh/gas_turb_h/crsohbilder/crs5aen/sld021.htm [Broken]Degree of reaction is the ratio of static enthalpy drop across the turbine rotor to the drop across the turbine stage.