Transient modelling and analysis of the OP16 gas turbine in GSP

Transient modelling and analysis of the OP16 gas turbine in GSP

Singh, V.

Axelsson, L. (mentor)
Visser, W.P.J. (mentor)

Aerospace Engineering

Flight performance and Propulsion

2015-12-17

With the current trend towards flexible engine operation with high efficiency and low emissions, dynamic modelling of gas turbines has become critical to ensure safe and acceptable engine performance. Dynamic models are essential for design and development of control systems and for analysis of transient manoeuvres that are impractical to test. This M.Sc. thesis project is carried out in collaboration with OPRA Turbines B.V. The aim of the project is to develop a dynamic model of the OP16 gas turbine. OP16 is a single-shaft all-radial industrial gas turbine rated at 1.9 MW, manufactured by OPRA Turbines. The resulting model can be used to simulate and analyse transient performance of the OP16 engine during manoeuvres of interest to OPRA Turbines. The model can also be used for designing initial fuel control strategies. The Dutch National Aerospace Laboratory’s Gas turbine Simulation Program (GSP) is used as the modelling platform. GSP is a 0-D, component based modelling environment that allows for steady-state and transient performance simulation of any gas turbine configuration. Since transient simulation in GSP is follows the quasi-steady-state approach, the steady-state model of OP16 is first developed. In order to evaluate the influence of steady-state heat loss on engine performance, thermal network modelling is also included. The steady-state model is verified against measured data across the entire operational envelope of OP16. The model is found to accurately simulate the steady-state performance of OP16 near the full load operating point. The steady-state model is extended to simulate transient performance of OP16 by implementing engine-specific details. The transient model is verified by comparing model simulations to the measured data for a load step near the full-load operating point. The transient effects including rotor inertia, heat soakage and volume dynamics are analysed to determine their influence and importance for the transient behavior. Rotor inertia is found to dominate the transient behaviour of OP16 while heat soakage effects and volume dynamics remain negligible in comparison. The transient model of OP16 is used to simulate engine behaviour when performing load sheds. The influence of fuel heating value, fuel valve closing time and combustor volume is analysed. One important aspect to guarantee safe operation is to be able to shut-off the fuel supply as soon as possible in case of an engine trip. From the simulations it is found that lower LHV fuels tend to result in higher rotor over-speeds in case of a load shed. For a LHV as low as 5.8 MJ/kg, the fuel valve closing time during a load shed should not exceed 0.7 seconds in order to maintain the rotor over-speed within acceptable limits, whereas for natural gas type of fuels the fuel valve closing can be up to 0.9 seconds.

gas turbine
transient performance analysis
GSP

http://resolver.tudelft.nl/uuid:e134587d-da8c-4f47-b4a6-bcec254a1ef5

2019-12-16

Student theses

master thesis

(c) 2015 Singh, V.