What are the differences between impulse and reaction turbines?
• The impulse turbine is characterized by the fact that it requires nozzles and that the pressure drop of steam takes place in the nozzles. • The reaction turbine, unlike the impulse turbines has no nozzles, as such. It consists of a row of blades mounted on a drum. The drum blades are separated by rows of fixed blades mounted in the turbine casing. These fixed blades serve as nozzles as well as the means of correcting the direction of steam onto the moving blades. • In the case of reaction turbines, the pressure drop of steam takes place over the blades. This pressure drop produces a reaction and hence cause the motion of the rotor. • What are the disadvantages of velocity compounding? Answers: • Steam velocity is too high and that is responsible for appreciable friction losses. • Blade efficiency decreases with the increase of the number of stages. • With the increase of the number of rows, the power developed in successive rows of blade decreases. For as much as, the same space and
