TG415 - Design and Major Repair of Steam Turbines

4.5 days - 2.9 Continuing Education Units Awarded

This course is designed for power generation engineers, operations superintendents and maintenance superintendents familiar with steam turbine components and the most basic steam turbine design theory.  The course is extremely helpful for those engineers who want to become familiar with turbine design and also desire to “take charge” of steam path upgrades, modifications and/or major maintenance and to learn those penetrating questions and evaluate the contractors answers, all based on “knowledge gained”.  The course is scheduled for 4.5 days of classroom work; each topic is covered in sufficient detail in class.  The attendee is also directed toward independent study using several textbooks, detailed course notes and a list of references included with the course.  Depending on the number of attendees, there may be some opportunity to discuss case studies with which the instructor has experience or problems attendees may have and which are of interest to all attendees.

Upon completion of this course the participant will be sufficiently familiar with the design of large utility steam turbines to participate in or lead major maintenance projects, steam path upgrades and/or modifications which commonly required as part of service life extension programs for fossil fired or nuclear power plants.  The participant will be better equipped to discuss design details with the original equipment manufacturer or the supplier of the steam path upgrade or modification.

INTENDED AUDIENCE
This course is designed for engineers who are new the power generation or those that are considering upgrades.

COURSE OUTLINE

1. STEAM POWER CYCLES
   1. The Carnot Cycle
   2. The Rankine Cycle
   3. The Steam Reheat Cycle
   4. Regenerative Feedwater Heating
   5. The Power Cycle - Mollier Diagram
   6. Cycle and Unit Efficiency
   7. Losses in the Steam Path
   8. Steam Path Deterioration
   9. Stage Velocity Ratio
   10. Turbine Steam Path Arrangements
   11. Valve Arrangements
       1. Partial Arc (Throttle Control)
       2. Full Arc (Nozzle Control)
   12. Initial Steam Conditions
   13. Reheat Section Steam Conditions
   14. Intermediate Pressure Section Steam Conditions
   15. Turbine Exhaust Pressure
   16. The Effects of Internal Moisture Separation
   17. The Removal of Feedwater Heaters from Service
   18. The Power Cycle Heat Balance
2. BLADE PROFILES
   1. The Blade Profile
   2. Blade Profile Pitching
   3. Vane Profile Design
   4. Determination of Profiles
      1. Impulse Profile of Constant Width Channel
      2. Impulse Profile with Converging Channel
      3. Aerodynamic Profile
   5. Blade Profile Variation with Vane Height
   6. Blades with Constant Profile
   7. Straight Generated Profiles
   8. Vortex or Twisted Profiles
   9. Passage Flow Capacity
   10. Radial Variation of Stage Parameters
3. STRESSES IN BLADE VANE
   1. Centrifugal Stress
   2. Modification of Simple Stress Diagram
      1. Root Blending Radius
      2. Lacing or Tie Wire
      3. Tip Thickening for Shroud Attachment
      4. Tip Thinning
      5. Leading Edge Erosion Shield
   3. Vane Bending Stresses
   4. Steam Bending Effects
   5. Centrifugal Bending Effects
   6. Blade Vibratory Stresses
   7. Blade Thermal Stresses
4. STEAM PATH ALIGNMENT
   1. Concepts Affecting Design Clearances
      1. Rotor Deflection
      2. Differential Expansion
      3. Radial Expansion of Steam Path Components
      4. Diaphragm Deflection at Pressure and Temperature
   2. Steam Path Area Relationships
   3. Steam Path Component Alignment
      1. Rotor Assembly and Requirements
      2. Diaphragm or Fixed Blade Row
   4. Circumferential Alignment Requirements
   5. Leakage Areas
   6. Steam Turbine Foundations
   7. Steam Turbine & Generator Line Out and Erection
      1. Lower Half Casing and Initial Bearing Adjustment
      2. Adjustment of Inner Casing
      3. Installation of the Diaphragms
      4. Tops on Alignment
      5. Installation of the Rotor in the Casing
      6. Measurement of Coupling Settings
   8. Alignment and Leveling Methods
      1. Center Line Wire Method
      2. Laser Method
5. BLADE ROOTS AND FASTENERS
   1. Functions of the Root
   2. Root Forms
      1. Axial Entry
      2. Radial Entry
      3. Tangential Entry
   3. Blade Root Platforms
   4. Blade Root Variation in Pitch
   5. Root Load Bearing Surface Curvature
   6. Tangential Entry Closing Blades
      1. The Closing Window
      2. Closure of the Window
   7. Pinning of Radial Entry Roots
      1. Blade Radial Positioning
      2. Tangential Placement
      3. Root Ligament Clearance
   8. Root Side Grips of Tangential Entry Blades
   9. Unequal Load Sharing within Blade Roots
      1. Radial Entry Type
      2. Axial Entry Type
      3. Tangential Entry Type
   10. Incorrect Radial Alignment of Rotor Blades
   11. Factors Influencing Blade Pitch Errors
   12. Blade Root Operational Problems
       1. Fatigue Failure in the Root
       2. Root Side Grips
       3. Root Fillet Radii
       4. Corrodents in the Root
       5. Tangential Entry Closing Blade Root Growth
   13. Blade Root Steeples
       1. Remedial Action
6. BLADE ROOT STRESSES
   1. Radial Entry (Pinned Root Form)
   2. Tangential Entry Form
   3. Axial Entry Form
   4. Closing Blades and Windows
   5. Considerations of the Blade Root Transfer Surface
7. COVER BANDS (SHROUDING) AND TIE-WIRES
   1. Functions of the Cover Band and Tie Wires
   2. Types of Tie and Lacing Wires
      1. Wire Cross Sections
      2. Continuous Wires
      3. Wire Ends
      4. Integral Wire
      5. Staggered Wire
   3. Types of Cover Bands/Shrouding
      1. No seal
      2. Axial seal
      3. Radial seal
      4. Axial seal and Radial platform
      5. Radial seal platform
      6. Special design bands
   4. Tenons and their Attachment by Riveting
      1. Types of Tenons
      2. Tenon and Hole Requirements
      3. The Rivet
   5. Shaping of Shroud Band Ends
   6. Cover Band Manufacture
   7. Riveting
8. TURBINE ROTORS
   1. Rotor Construction
      1. Monoblock/Integral
      2. Built up
      3. Welded
   2. Function of the Rotor
   3. Rotor Heat Treatment
   4. Inspection of Rotor Bores
   5. Inspection of the Forging
   6. Critical Speed
   7. Vibration of Turbine Rotors
   8. Rotor Thermal Stabiltiy
   9. Rotor Stresses
   10. Rotor Temperature Control
   11. Turbine Rotor Discs
       1. Functions of the Disc
       2. Types of Discs
       3. Assembly of Discs on Shaft
       4. Disc Removal
       5. Disc Stresses
       6. Keyways and Securing
       7. Overspeed Testing
9. TURBINE FIXED BLADES AND DIAPHRAGMS
   1. Function of Fixed Blades and Diaphragms
   2. Diaphragm Construction and Manufacture
   3. Built up Fixed Blade Rows
   4. Diaphragm Stresses and Material Evaluation
10. BLADE VIBRATION
    1. Prediction of Blade Frequencies
    2. Sources of Vibration Stimulus
    3. General Equation for Blade Frequencies
    4. Torsional Vibration
    5. Correction Factors for Natural Frequency
    6. The Campbell Diagram
    7. Nozzle Impulse Effects
       1. Partial Admission
       2. Steam Force Diagram
       3. Nozzle Passing Effect
    8. Blade Off-Frequency Operation
11. STEAM TURBINE CASINGS
    1. Pressure Staging and Multiple Shells/Cylinders
    2. Functions of the Cylinders/Shells
    3. Thermal Gradient and Shell Design
    4. Estimating Low Cycle Fatigue Life
    5. Shell Manufacture
    6. Shell Casting Defects
    7. Steam Inlet Connection Points of the Casings
    8. Steam Nozzle Boxes
12. MATERIALS for STEAM PATH and other TURBINE COMPONENTS
    1. Alloying Elements
    2. Mechanical Properties of Turbine Materials
       1. Tensile Strength
       2. Yield Strength
       3. Ductility
       4. Hardness
       5. Impact Strength
       6. FATT
       7. Modulus of Elasticity
       8. Modulus of Rigidity
       9. Fatigue Strength
       10. Creep Rupture
       11. Poisson's Ratio
       12. Resistance to Corrosion
       13. Coefficient of Thermal Expansion
       14. Diffusivity
       15. Thermal Conductivity
    3. Rotor Forging Material
    4. Turbine Disc or Wheel Material
    5. Blading Materials
       1. Precipitation Hardening Steel for Blades (17-4PH)
       2. Titanium Alloy for Blades
    6. High Pressure and Temperature Casings