In a single stage Parson’s reaction turbine, the mean blade velocity is observed to be 60 m/s and the nozzle angle to be 20°. Determine the the entrance angle of moving blade if the absolute velocity of the steam leaving the nozzle is 120 m/s.

Correct Answer: 38°
Cbl = 60 m/s, α = 20°, C1 = 120 m/s Steps of ConstructioSelect a suitable scale and draw a line LM to represent Cbl (=60 m/s). At point M, at an angle of 20° (α), cut a length MS to represent the velocity C1 (=120 m/s). Join LS. Produce L to meet the perpendicular drawn from S at P. Thus inlet triangle is completed. By measurement: θ = 38°.