**Courses offered by Laboratory of Thermal Turbomachines**

**Thermal Turbomachines****Design of Thermal Turbomachines****Experimental Fluid Mechanics****Gas and Steam Turbine Operation****Principles of Jet Propulsion****Aircraft Engine Operation****Viscous Flows in Turbomachines****Optimization Methods in Aerodynamics****Gas Turbine Diagnostics****Numerical Analysis**

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Introduction to the morphology, operation and aerothermal analysis of thermal turbomachines. Types of thermal turbomachines, compressor, turbine, steam-turbine. Fundamental governing equations. One-dimensional flow in thermal turbomachines. Flow analysis in two-dimensional cascades. One-dimensional flow analysis in axial and radial compressors. One-dimensional flow analysis inaxial and radial turbines. Single-and multi-stage turbomachines. Turbine and compressor similarity. Basic mechanical features. Experiment in the Lab: Experimental determination of a compressor characteristic curve. Project on turbomachinery computations.

Lab: C 5%of the Final Grade Project/s: C 5% of the Final Grade

Teachers: K. Giannakoglou, Ch. Romesis (SLTS*)

**Design of Thermal Turbomachines**

Basic principles of compressor and turbine design. Selection of rotational speed and annulus dimensions. Determination of number of stages. Flow angle calculation across blade height (quasi-three-dimensional flow). Radial equilibrium equation. Comparison of different radial distributions of peripheral velocity. Investigation of compressibility effects. Blade profile selection using cascade experimental data. Blade design. Calculation of efficiency using empirical loss equations and experimental data. Calculation of performance maps. Laboratory exercise: measuring the flow field inside an axial compressor stage. Computational project: design of an axial compressor or turbine.

Lab: C 10% of the Final Grade Project/s: O 30%of the Final Grade

Teachers: K. Mathioudakis, N. Aretakis, Ch. Romesis (SLTS*)

Basic characteristics of measuring instruments. Measurement errors. Signal digitization. Fourier analysis. Operation principles of various measuring techniques like Hot wire anemometry, Laser Doppler anemometry, Particle Image Velocimetry, Pitot and Pitot Static tubes, tubes of many holes, flow rate meters, viscometers, ultra sound, shear stress measurement, pressure measurement, flow visualization. In the context of this course, 6 exercises are carried out, applying some of the above techniques.

Project/s:C 25%of the Final Grade

Teachers: D. Mathioulakis, D. Bouris, N. Aretakis, Ch. Manopoulos (SLTS*)

**Gas and Steam Turbine Operation [C]**

Gas Turbines: Types and layout of gas turbines. Cycle analysis, performance parameters. Features of compressors and turbines. Blade cooling. Combustion, combustion chambers, fuels. Operation under varying loads, control methods. Performance simulation. Gasturbine set up, subsystems.

Steam turbine: Steam cycles and steam turbine. Stage analysis, types, operation. Performance parameters, losses, efficiency. Operation under varying loads, control. Performance simulation. Wet steam turbine features.

Principles of maintenance, condition monitoring and fault diagnosis of gas and steam turbines. Performance diagnostics. Aerothermodynamic diagnostics and vibration diagnostics.

Teachers: K. Mathioudakis, N. Aretakis, Ch. Romesis (SLTS*)

**Principles of Jet Propulsion [C]**

Thrust generation, equations for thrust calculation, factors influencing thrust. Comparative presentation of different jet-engine layouts. Description of the main parts of a jet engine. Cycle analysis and performance calculations. Parametric design studies. Inlets analysis, design principles, subsonic, supersonic. Exhaust nozzles, operational principles, convergent, convergent divergent. Mixers. Layout and operational principles of compressors, burners and turbines. Blade cooling. Component matching for equilibrium operation. Cycle analysis and performance calculations for different operating conditions, reduced performance parameters. On-aircraft engine operation for different flight conditions.

Project/s: C 20%of the Final Grade

Teachers: K. Mathioudakis, N. Aretakis, Ch. Romesis (SLTS*)

Operation analysis of turbo combustion engines and calculation methods of the operation performance. Computational models of aircraft engines, modeling of engine components, determination of engine characteristics and methods for developing computer modelsof the operation of aircraft engines.Principles of operation and types of auxiliary systems for aircraft engines. Engine use in relation to a specific aircraft, according to its mission analysis. Environmental impact of engines by emissions of gas pollutants as well as noise emissions. Engine certification.

Project/s: C 10%of the Final Grade

Teachers: N. Aretakis, K. Mathioudakis, Ch. Romesis (SLTS*)

**Viscous Flows in Turbomachines**

Boundary layer and viscous flow theory. Incompressible and compressible viscous layers in compressor and turbine bladings. Differential and integral methods for viscous flow modeling in turbomachines. Viscous-inviscid interaction methods in turbomachinery. Turbulence and transition modeling in turbomachines. Secondary flows and relevant computational methods. Tip clearance flows in turbomachines and their modeling. Advanced case studies.

Teacher:K.C. Giannakoglou

**Optimization Methods in Aerodynamics**

Inverse design and optimization problems in aerodynamics. Objectives in design problems. Shape optimization problems with inviscid and viscous flow considerations. Numerical optimization: mathematical background, optimization without or with constraints, single-and multi-variate optimization, single-and multi-objective optimization, iterative optimization methods (sequel to methods known from the Numerical Analysis course), existence and uniqueness of the optimal solution, advantages and limits of numerical optimization methods. Automatic differentiations, direct differentiation, the complex variablemethod, the continuous and discrete adjointmethod. Applications. Stochastic optimization methods based on evolutionary algorithms and artificial intelligence. Advantages and disadvantages. Applications.

Project/s: O 50%of the Final Grade

Teacher: K. Giannakoglou

The need and importance for gas turbine engine condition monitoring. Relation to on-condition maintenance. Measured quantities and methods, data collection for monitoring. Systems and methods for condition assessment and fault diagnosis. Gas path analysis: direct methods, estimation methods, linear, non-linear. Trending. Use of fast response measurements (sound, vibration). Elements of life assessment methods. Data evaluation, artificial intelligence methods. Jet engine testing, testing procedure, parameter corrections. The use of computers for monitoring methods support.

Lab: C 10%of the Final Grade

Teachers: N. Aretakis, K. Mathioudakis, Ch. Romesis (SLTS*)

Systems of linear equations: Direct (Gauss elimination, factorization) and iterative (Jacobi, Gauss-Seidel, SOR) solution methods. Eigen problems and the power method. Interpolation and polynomial regression: Taylor, Lagrange, Newton and Hermite polynomials. Spline interpolation. Nonlinear equations: bisection, regula-falsi, fixed-point iterative methods, Newton-Raphson, the secant and Schroder methods. The Newton’s method for systems of nonlinear equations. Numerical differentiation and integration. Approximation of derivatives. Simple rules for numerical integration. Gaussian quadrature. Integration of improper integrals. Differential equations. The Initial-value problem, Numerical errors. One-step methods (Taylor, Runge-Kutta). Multistep methods (Adams, prediction-correction). Regression theory. Least-squares regression (polynomial, exponential). Least-squares with orthogonal polynomials. Boundary-value problems. Partial derivatives approximation. The linear shooting method. Finite difference methods.

Project/s & Subjects: O 30%of the Final Grade

Teachers: Κ. Giannakoglou, S. Voutsinas