1. Design of Steam & Gas Turbines
P.M.V. Subbarao
Professor
Department of Mechanical Engineering
Indian Institute of Technology, Delhi
A Table of Geometrical Details…..

2. Multistage Impulse Turbine : GE Product

4. What If it is A Single Stage Impulse Turbine

10. 500 MW Steam Turbines in Indian Power Plants
m_hp
m_ip
m_lp
Mass Flow rate
(tons/hr)
1534
1380
1141 MS
CRH
HRH
Ex 5
Ex 4
Ex 3
Ex 2
Ex 1
Cond
P (MPa)
T (0C)
h (kJ/kg)
Mass flow rate (kg/s)
16.677
537
3396
4.454
344.8
3069
4.013
3530
766.67
1.922
430.4
3316
26.81
0.7456
300.6
3060
19.12((BFP)
22.09
0.267
194.8
2857
12.47
0.1361
135.8
2745
22.62
0.0278
67.37
2507
10.13
0.0092
44.15
2386

11. Plant Layout & Energy Balance Diagram

13. Approximate Rotor Inlet Conditions

14. General Rules for Steam Path Design
For HP Axial (flow) velocity at the inlet is 40 m/sec and at the outlet 65 m/sec. (> 5 Mpa)
 For IP axial velocity of steam at the inlet is 60 m/sec and at the outlet 80 m/sec (5 Mpa – 0.3 Mpa)
 For LP axial velocity of steam at the inlet is 75 m/sec and at the outlet of last front stage is 130 m/sec. (<0.3 Mpa)
Maximum mean blade speed used so far: 450 m/s
Generally acceptable range of inlet flow angle(a1) : 150 to 200

15. Inlet Velocity DiagramU
Vr1
Va1
Vr2
Va2 b1 a1 a2 b2

16. U
Vr1
Va1
Vr2
Va2 b1 a1 a2 b2

17. Steam turbine design

18. y F

19. With known value of U , change enthalpy is obtained .
For reaction turbine maximum efficiency occurs at loading factor
From change in enthalpy absolute velocity of steam can be obtained

21. Range of turbine Design Parameter
High Pressure Gas Turbine:
Maximum AN2 : 2.5×107 – 3.3 ×107 m2.rpm2.
Stage loading coefficient: 1.4 – 2.0
Stage Exit Mach Number: 0.4 – 0.5
Low Pressure Gas Turbine:
Inlet mass flow rate: 195 – 215 kg/m2.s
Hub/tip ratio:
Max. Stage loading (based on hub): 2.4
Exit Mach Number: 0.4 – 0.5

22. L/F=2
L/F=1
L/F=0.5
L/F=0
(b1+b2) b1

23. 90-a2
90-b1
F=0.5
90-a1

24. (b1+b2) b1