1. More Discussions on Irreversible Flow Thorough Multi- stage Turbines P M V Subbarao Professor Mechanical Engineering Department Continuous Opportunities to recover losses……

2. Irreversible steam path in Multi Stage turbine 3 4s 4 II s 4 III s 4Is4Is 4Ia4Ia 4 II a 4 III a 4Vs4Vs 4 IV s 4 IV a 4Va4Va 4 VI s 4 VI a T s

3. Global Effects in a Multi Stage Impulse Turbine Global available enthalpy for Power: 3 4s 4 II s 4 III s 4Is4Is 4Vs4Vs 4 IV s 4Ia4Ia 4 II a 4 III a 4 IV a 4Va4Va 4 VI s 4 VI a Internally available enthalpy for Power: Total actual stage work output per unit mass: 4 II ss 4 III ss 4 IV ss 4 V ss

4. Define Stage Efficiency:

5. Global internal efficiency of turbine: Global Efficiency of A Multistage Turbine

6. Behavior of Superheated Steam h, kj/kg s, kJ/kgK

7. Improving Bountifulness of Steam  h, kj/kg s, kJ/kgK

8. Well Behavior of Superheated Steam T

9. Internal Reheating due to Irreversibilities 3 4s 4 II s 4 III s 4Is4Is 4Ia4Ia 4 II a 4 III a 4Vs4Vs 4 IV s 4 IV a 4Va4Va 4 VI s 4 VI a T s

10. q i is always positive. Therefore, Multistage turbines will increase the possibility of recovering lost availability! The larger the number of stages, the greater is the heat recovery. The difference is called heat recovery factor, a. General value of  is 0.04 to 0.06. The Reheat Effect without burning fuel

11. Losses Responsible for Blade Local Polytropic Efficiency Also known as Group I losses. Guide profile loss. Runner profile loss. Guide secondary loss. Runner secondary loss. Guide annulus loss Runner annulus loss

12. Spatial Variation of Group – 1 Losses Profile loss is essentially variable and calculable along the blade height. Secondary loss can be evaluated separately for root and tip conditions. Annulus losses occur between blades but these losses are essentially one-dimensional and should not be applied as a variable along the blade height.

13. Profile & Local Mach Number The flow velocity is different on different positions on the wing. Let the Mach number of the flow over our wing at a given point x be M x. The corresponding pressure coefficient can then be found using