MME508

Unit Description and General Aims

Gas Turbines are vital pieces of equipment in many industries. Engineers must have knowledge of them; either superficially, or in depth, depending on the engineer’s area of responsibility. The former will be for basic operation and minor maintenance, the latter for installation and heavy maintenance of the units.
In this topic the first aspect addressed is as to where, or if, gas turbines are needed in preference to other prime movers. This depends on the processes being supported, location, expected reliability level, financial considerations and environmental effects. Students will be given templates to help them make calculations leading to correct decisions.
This unit will cover the operation and maintenance of gas turbines. Components covered will include gas compressor types (centrifugal, axial and mixed flow), combustor designs, turbines and exhaust systems. The selection of materials for improved power, efficiency and engine life will be covered. Aero-thermal operations will be studied. The student will also learn about heat recovery systems, COGEN and Combined Cycle. As well as the many systems that makes up any gas turbine installation. Gas turbine operation will be covered, with maintenance, inspection and repair practices, especially where in-house actions can bring about significant savings vis-a-vis contracting these activities to OEMs.

Learning Outcomes

On successful completion of this Unit, students are expected to be able to:

1. Judge the economics, and other factors, for installing gas turbines in preference to other prime movers.
   • Bloom’s Level 5
2. Determine in detail the construction of a gas turbine engine, its major components and their aero-thermal interactions.
   • Bloom’s Level 5
3. Critique all gas turbine operating phases and be able to discover where both minor- and major maintenance is necessary.
   • Bloom’s Level 5
4. Synthesise existing -and recommend - new applications for gas turbines. To be able to evaluate, from given data, efficiencies and economic feasibilities of Combined Cycle as well as COGEN facilities.
   • Bloom’s Level 6
5. Make judgements based on information to optimise both gas turbine operation and maintenance practices; and reflect on the veracity of information and the commercial and regulatory implications on their use for power generation and other applications such as COGEN.
   • Bloom’s Level 5
6. Construct a rudimentary gas turbine using one of several available design packages, this will enhance understanding of the Brayton Cycle and practical limitations on achieving the ideal cycle.
   • Bloom’s Level 6

Student assessment

Prescribed and Recommended readings

Required Textbook (One Required reading, which covers at least 60% of weekly topics)

• M.P. Boyce, Gas Turbine Engineering Handbook, 4th edition, Gulf Publications, Houston,2012

Reference Materials

Other texts, peer-reviewed journals and websites (Others may be advised during lectures).

• Gas Turbines: Fundamentals, Maintenance, Inspection and Troubleshooting, 7th revision, IDC Perth Australia publication
• C. Soares, Gas Turbines, A Handbook, 2nd edition, Butterworth-Heinemann, Burlington MA, 2015
• The Jet Engine, Rolls-Royce plc, 6th edition, Derby England, 2005
• T. Giampaolo, Gas Turbines Principles and Practice, 6th edition, Fairmont Press, Lilburn GA, 2012 (Available from Kindle)
• Rolf Kehlhofer, Combined-cycle gas and steam turbine power, Fairmont Press, Lilburn GA, 1991
• GSP 11 Gas Turbine Simulation Program, File version 11.4.0.0 (Shareware), National Aerospace Laboratory of the Netherlands, Amsterdam

Unit Content

One topic is delivered per contact week, with the exception of part-time 24-week units, where one topic is delivered every two weeks.

Topic 1

Introduction to Gas Turbines – Part 1

A brief history of gas turbine development; including gas turbine types, their construction and operation

• Gas turbine evolution, History
• Technical improvements
• Economic Comparison of Various Generation Technologies
• Categories of Gas Turbines - Types
  • Frame Type Heavy-Duty Gas Turbines.
  • Aircraft-Derivative Gas Turbines
  • Industrial Type-Gas Turbines
  • Small Gas Turbines.
  • Micro-Turbines.
• Simple cycle gas turbine
• Regenerative gas turbine
• Gas Turbine Performance
• Major Gas Turbine Components

Physics as applicable to gas turbines

• Basics of:
  • Fluid flow theory
  • Velocity vectors
  • Reynolds number
  • Bernoulli’s theorem

Required knowledge of thermodynamics and aerodynamics

• Fundamentals:
  • Enthalpy, Entropy, Work done calculations
  • T-S and H-S diagrams, Efficiency etc.
• Theoretical and Actual Cycle Analysis
• Reversible cycles with ideal gases
• The Brayton Cycle
  • Constant pressure or Brayton cycle layout
  • Basic work and efficiency calculation
• Ideal inter-cooled and reheat cycles
• Blade profile nomenclature
• Elementary Airfoil Theory
• Laminar-Flow Airfoils

Topic 2

Introduction to Gas Turbines – Part 2

Various gas turbine cycle layouts

• Actual gas turbine cycles
• The Brayton-Rankine Cycle
• The Regenerative Cycle
• The Intercooled Simple Cycle
• The Reheat Cycle
• The Intercooled - Regenerative Reheat Cycle
• The Steam Injection Cycle
• The Evaporative Regenerative Cycle
• Combined Cycle Plants
• Comparison of power output and efficiency of the above cycles.

Introduction to utilisation economics

• Fuel economics
• Plant Power Optimization
• On-line Optimization Process
• Life Cycle Costs

Detailed description of all gas turbine engine configurations, major components and selection of materials

• Compressors
  • Centrifugal Compressors
  • Axial-Flow Compressors
• Turbines
  • Radial-Inflow Turbines
  • Axial-Flow Turbines
• Combustors
• Gas Turbine Materials
• General metallurgical behaviour in gas turbines
• Coatings
• COGEN and Combined Cycle plants
• COGEN** – Co-generation
• Combined cycle plants

Topic 3

Engine systems, the environment – Part 1

Cooling systems, bleeds

• Inlet Cooling
• Evaporative Cooling of the Turbine
• Absorption Cooling Systems
• Turbine Blade Cooling Design
• General metallurgical behaviour in gas turbines

Bearings, Bearing Design Principles

• Tilting-Pad Journal Bearings 
• Bearing Materials
• Bearing and Shaft Instabilities 
• Thrust Bearings, Factors Affecting Thrust-Bearing Design
• Thrust-Bearing Power Loss

Seals, Noncontracting Seals, Mechanical (Face) Seals

• Mechanical Seal Selection and Application, Seal Systems
• Associated Oil System. Dry Gas Seals.

Topic 4

Engine systems, the environment – Part 2

The lubrication system

• Basic Oil System
• Lubricant Selection
• Oil Sampling and Testing. Oil Contamination.
• Filter Selection. Cleaning and Flushing.
• Coupling Lubrication.
• Lubrication Management Program

Fuel systems, liquid and gas, fuel properties, treatment and storage on site

• Fuel Specifications.
• Fuel Properties.
• Fuel Treatment.
• Heavy Fuels.

Topic 5

Engine systems, the environment – Part 3

Auxiliary systems: starting, ignition, instrumentation, fire protection, air filtration, misting

• Starting system
• Control Systems. Condition Monitoring Systems. Monitoring Software
• Implementation of a Condition Monitoring System

Inlet Air Filters, Inlet Air Cooling

• Water injection for power and air pollution control,
• Sound suppression methods.
• Environmental standards

Topic 6

Gas turbine operation, inspection, maintenance, repair and troubleshooting – Part 1

Engine operating requirements

• Lubrication, operation and maintenance of lubrication system
• Balancing, Orbital Balancing, Modal Balancing, Multiplane Balancing
• Couplings and Alignment, Gear Couplings, Metal Diaphragm Couplings
• Shaft Alignment, The Shaft Alignment Procedure

Operating safety considerations

• Acoustics and Noise Control,
• Noise criterion, Noise control methods
• Other safety precautions

Compressor characteristics of surge and stall. Compressor maps

• Compressor Stall, Rotating Stall, Individual Blade Stall, Stall Flutter,
• Stall Analysis of an Axial-Flow Compressor
• Fuel Control Units to maintain normal operation

Engine starting, running, short and long term shut-down procedures

• Start-up Sequence
• Starting preparations
• Shutdown method
• Generator protection

Topic 7

Gas turbine operation, inspection, maintenance, repair and troubleshooting – Part 2

Abnormal operation and its correction. Troubleshooting

• Diagnostic system-Spectrum Analysis-Vibration Measurement
• Detectable Problems:
  • Gas Path Analysis
  • Turbine Blade Distress
  • Compressor Fouling
  • Combustor Distress & Plugged Fuel Nozzles
  • Foreign/Domestic Object Damage
  • Worn Air/Oil Seals
  • Fuel Control Problems
• Condition Monitoring Systems, Monitoring Software
• Requirements for an Effective Diagnostic System
• Implementation of a Condition Monitoring System
• Campbell diagram

Operation when connected to an electrical grid, droop

• Grid frequency, control systems, Droop curves

Maintenance concepts, on- as well as off-load inspection methods

• Philosophy of Maintenance. Training of Personnel. Tools and Shop Equipment.
• Turbo-machinery Cleaning. Hot-Section Maintenance. Compressor Maintenance.
• Bearing Maintenance. Coupling Maintenance. Rejuvenation of Used Turbine Blades.
• Repair and Rehabilitation of Turbomachinery Foundations.
• Large Machinery Start-up Procedure
• Light and heavy maintenance planning, hot end inspections
• Following OEM requirements for inspection and repair, facilities and tooling

Topic 8 

Measuring engine performance, troubleshooting performance losses 

• Primary Measurements in GT (Pressure, Temperature, Flow)
• GT Testing
• Performance Curves / Maker’s Data
• What are Performance Curves
• How to read Performance Curves
• Performance and Data Correction
• Correction Curves
• Performance Equations
• Sample Calculations

Topic 9

Design a rudimentary gas turbine using a shareware software package

• Software for Gas turbine design
• GasTurb
• Smooth C and Smooth T
• Map Collection
• GasTurb DLL
• GasTurb Details
• GasTurb Names
• GasTurb 13
• How to Calculate a Single Cycle
• Case Study

Topics 10 and 11

Further study and research on industrial gas turbines

• This report is far-reaching in its scope and will enable the student to show a good understanding of his/her knowledge of this topic. It will also give the student, to his/her credit, the ability to cover/emphasise aspects of gas turbines that may not have been fully dealt with in the above content.
• Use the gas turbine design developed and simulate steady state and transient conditions. Generate operating report.
• The student will also be asked to critically discuss selected aspects of current research and development underway.
• 5 or 6 latest academic publications from international journals can be provided to the students. Students may be asked to analyse any one of these papers and provide a report based on a predefined framework (Framework will be provided).

Topic 12

Project and/or Unit Review

In the final week students will have an opportunity to review the contents covered so far. Opportunity will be provided for a review of student work and to clarify any outstanding issues.  Instructors/facilitators may choose to cover a specialized topic if applicable to that cohort.

• Review/Refresher slides containing an overview of whatever is covered in the course. May add pop quizzes to refresh memory.
• Analysis of different types of gas turbines being used in various industries with an elaboration on the reasons for their selection.

Engineers Australia

The Australian Engineering Stage 1 Competency Standards for the Professional Engineer, approved as of 2013. This table is referenced in the mapping of graduate attributes to learning outcomes and via the learning outcomes to student assessment.

 Software/Hardware Used

Software

• Software: GasTurb

• Version: N/A

• Instructions:  N/A

• Additional resources or files: N/A

Hardware

• N/A

Unit Changes Based on Student Feedback