Gas Turbine Simulations in the Computerized Educational Program CompEduHPT: Three Case Studies
Authors: Salomo´n Marianne , Fridh Jens , Kessar Alexandros , Fransson Torsten 
Published: February 2009

In this paper three different kinds of simulations present in the Computerized Educational Program (CompEduHPT) will be described and discussed. The main objective of these examples is to describe in detail some of the simulations and the educational aspects associated. The first example is the simulation of a Real Gas Turbine calculation procedure. CompEduHPT includes several simulations in the Heat and Power Cycles part and particularly on gas turbines. These simulations give the student an outlook of the different parameters that affect the performance based on the ideal and real approach of gas turbine’s calculation. Five simulations regarding real gas turbine calculations are included in CompEduHPT. These simulations have the purpose to show the students the different aspects, effects and results when a calculation is made considering a mixture of two ideal gases (pure air and combustion gas). At the same time they also show the improvements in the performance of the gas turbine depending on the different options available such as intercooling, reheating, regeneration and intercooling. The calculation of these cycles using an approximation to real conditions allows the students to compare with the ideal calculation process and also to compare between the different gas turbine cycles. Another example that will be explained in detail is related to turbine’s aerothermodynamic simulations. There are several simulations based on simple 2D velocity triangle theory, where not only velocities and flow angles across a turbine stage are included but also expansion, specific work, reaction, design parameters and losses. This provides the user with an easy-to-use powerful tool for understanding of the principal coupling between different parameters. By changing input values the user can visually and numerically see the effect of selected parameters. The inputs can be altered among a variety of parameters such as inlet velocity, blade speed, flow angles and turbine design parameters. The selected simulation on Aeroelasticity is one of the numerous simulations that can be found in CompEduHPT under this topic. It represents a simplified airplane wing (as flat plate), under vibration. The purpose of this simulation is to demonstrate the importance of the phase angle between the bending and the torsion branches of a coupled bending/torsion vibration. One of the main objectives of this simulation is for the students to be able to see that the value and the direction of the force for each moment are dependant on the phase lag between bending and torsion. The key issue for the students going through this simulation is to realize that if the force and the velocity have the same sign, the power is positive. On the contrary, it is negative if the signs of the force and the velocity are different. Finally, but not less important, is to observe what kind of an influence does the phase angle between bending and torsion have on the absorbed work: • If 0 &lt; phase angle &lt; 180 ⇒ Excitation; • If −180 &lt; phase angle &lt; 0 ⇒ Damping; • If phase angle = 0 or ± 180 ⇒ Neutral.