Inward flow turbine vs. Outward flow Reaction Turbine:

 

Inward Flow Reaction Turbine

Outward Flow Reaction turbine

01. Water flows the outer periphery of wheel towards the wheel centre and discharges at the inner periphery.

01. Water enters the wheel centre (inner periphery) and flows outward and discharges at the outer periphery.

02. The centrifugal head (U₂² - U₁²)/2 imparted to water as it flows through the turbine runner is negative, as U₂ is smaller than U₁

02. Water enters the runner with excess pressure and hence both pressure and velocity of water change as water passes through the runner.

03. Due to negative centrifugal head, relative velocity of water at the outlet is reduced.

03. Due to positive centrifugal head, relative velocity of water at the outlet is increases.

04. Discharge does not increase.

04. Discharge increases.

05. Less or no tendency of wheel to race if the turbine speed increases, as the turbine itself adjust the speed.

05. If the turbine speed increases, wheel tends to race as turbine by itself can not adjust the speed.

06. Effective and easy speed control is possible.

06. Speed control is difficult.

07. Used for large output and suitable for medium and high heads.

07. Used for low and medium heads.

08. Used often in power plants.

08. Obsolete.