Thermoacoustic instabilities in gas turbines
Lead Research Organisation:
University of Cambridge
Department Name: Engineering
Abstract
Gas turbines are the principal devices used for aerospace propulsion and power generation. Due to the fact that they involve hydrocarbon combustion, it is very important to ensure that their design is optimised in terms of stability, efficiency and emissions in order to meet the environmental targets set by the UK government for the next 30 years and reduce the production and operating costs. This project is aiming at investigating thermoacoustic instabilities, specifically azimuthal instabilities which appear in very late stages of a new engine development programme. So, changing engine design will prove to be very expensive. The OEMs are looking for ways to predict the occurrence of these instabilities so that it can be avoided at design stage itself, if possible. This project aims to provide such a capability and it is linked to the combustion, fluid dynamics, chemical reaction dynamics, energy efficiency and fossil fuel power generations EPSRC research areas.
There are two modes of instabilities observed in the gas turbines with annular burners. The first one is the longitudinal instability observed in the axial direction of the turbine. This is an area where extensive research has been done and a wide range of literature is available. The second one is the tangential thermoacoustic instability, which is the main focus area of this project. It is not well understood and by focusing the combustion research on this area the design of the gas turbine combustors could be significantly improved.
The current solution to that problem in both the aerospace and power generation industries is the use of sophisticated control systems which regulate the fuel flow independently on every burner compensating for the pressure surges. These kinds of remedies are very expensive in terms of time and money resources and therefore, a turbine design minimising the severity of that phenomenon in a physical way will be greatly beneficial to the industry.
This project is purely computational and split in two parts. The first one is to process the results generated from a previous project in the university. This involves post processing, interpretation and identification of the causes of the phenomenon. A range of computational tools is expected to be used, including 1D system level simulations software to study the wave characteristics of the pressure surges in the annular combustion chambers. Once a good understanding of the phenomenon is developed, the next task would be to run Large-Eddy Simulations (LES) which will be focused on areas deemed relevant and investigate how the pressure surges in the combustion chamber can be minimised to avoid the instabilities.
There are two modes of instabilities observed in the gas turbines with annular burners. The first one is the longitudinal instability observed in the axial direction of the turbine. This is an area where extensive research has been done and a wide range of literature is available. The second one is the tangential thermoacoustic instability, which is the main focus area of this project. It is not well understood and by focusing the combustion research on this area the design of the gas turbine combustors could be significantly improved.
The current solution to that problem in both the aerospace and power generation industries is the use of sophisticated control systems which regulate the fuel flow independently on every burner compensating for the pressure surges. These kinds of remedies are very expensive in terms of time and money resources and therefore, a turbine design minimising the severity of that phenomenon in a physical way will be greatly beneficial to the industry.
This project is purely computational and split in two parts. The first one is to process the results generated from a previous project in the university. This involves post processing, interpretation and identification of the causes of the phenomenon. A range of computational tools is expected to be used, including 1D system level simulations software to study the wave characteristics of the pressure surges in the annular combustion chambers. Once a good understanding of the phenomenon is developed, the next task would be to run Large-Eddy Simulations (LES) which will be focused on areas deemed relevant and investigate how the pressure surges in the combustion chamber can be minimised to avoid the instabilities.
Organisations
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/R513180/1 | 01/10/2018 | 30/09/2023 | |||
| 2275528 | Studentship | EP/R513180/1 | 01/10/2019 | 30/09/2022 | Dimitrios Kallifronas |
| Description | This work is focused on the thermoacoustic behaviour of lean premixed swirling flame. To understand the physical processes present in such reacting flows, one must have a fundamental understanding of the relevant fluid dynamics and mechanisms. For this part of the work a series of computer simulations have been run to understand the effect of swirl and heat release on the flow structure. The knowledge developed from this stream of work, which lead into a publication, was used as a foundation to perform further simulations to understand the effect of swirl on flame response to acoustic perturbations. This work is currently ongoing. |
| Exploitation Route | Lean swirling flames are highly applicable in aviation and industrial gas turbine industry. Understanding the thermoacoustic behaviour of swirling flames can help manufacturers predict combustion instabilities which can cause structural damage to gas turbines. Over the last decade, there has been a growing scientific interest in the thermoacoustics of swirling flames and there are still physics to be explored. Therefore, there is a lot of potential to take this work forward in the academia as well. |
| Sectors | Aerospace, Defence and Marine,Energy,Transport |