Impulse Turbine | Reaction turbine |
01. Energy available at the inlet is in the form of kinetic energy | 01. Energy available at the inlet is in the form of kinetic and pressure energy |
02. Pressure acting buckets is constant and atmospheric throughout the action of water on the runner till it is discharged to the tail race. | 02. Water enters the runner with excess pressure and hence both pressure and velocity of water change as water passes through the runner. |
03. Water does not fill the vanes and casings and air has free access to the buckets. | 03. Water fills completely the vanes and buckets throughout the turbine operation. |
04. Casing is used only to protect water from splashing and to guide water to the tail. | 04. Casing is essential to send the unit from atmospheric condition as the turbine inlet pressure is much higher than the outlet pressure. |
05. Turbine unit is installed above the tail race level. | 05. Turbine unit is completely submerged in water bellow the tail race level. |
06. Flow regulation does not result in possible loss. | 06. Flow regulation results in possible loss. |
07. As water passes over the guide vanes, its relative velocity reduces slightly or remains the same. | 07. As water glides over the vanes, its relative velocity increases due to continuous drop in pressure during flow through the blade passages. |