Tracer-free, non-intrusive, time- and space-resolved temperature and scalar measurements
Lead Research Organisation:
CARDIFF UNIVERSITY
Department Name: Sch of Engineering
Abstract
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Organisations
Publications
Weller L
(2024)
Spatial Temperature and Water Molar Concentration Measurements Using Thermal and Electrostrictive Laser-Induced Grating Spectroscopy During Operation of a Swirl Burner at Pressure
in Journal of Engineering for Gas Turbines and Power
| Description | See parent grant held at Cambridge/Hochgreb (EP/T030801/1) for detail ........ The growth in air transport, and the need for base and balance thermal power in an electricity-powered future centres creates a pressing need for low emission, high efficiency gas turbines, particularly regarding NO, CO and soot. The key variables determining the production of these pollutants in the product gases are the local instantaneous product gas temperature and the local fuel fraction. The large fluctuations in gas temperature, and the exponential dependence of pollutant production on temperature means that predictions of NO, CO and soot in combustion are not possible without suitable accurate statistics of instantaneous local temperature measurements. Yet there are very few such measurements in practical devices to validate models. Local instantaneous temperature measurements in high pressure radiant devices require optical techniques which are rather complex for industrial laboratories. This proposal aims to extend a much simpler technique for the purpose to allow tracer free local measurements of temperature, pressure and water vapour. Laser-induced grating spectroscopy (LIGS) has been shown to work even in highly radiant, soot-prone environments, and may also enable local measurements of additional target scalars (water vapour, pressure) using the easily accessible Nd:YAG laser wavelength of 1064 nm. The technique uses both the electrostrictive mode and weak absorption spectral lines in this wavelength range to enable measurements of both temperature and relative water concentrations in realistic devices. The signal to noise of the technique improves with pressure, a significant advantage for realistic devices, especially in environments such as gas turbines, which are prone to large amounts of radiant luminosity. The project will extend the current capabilities of the technique from point measurements to spatially resolved line measurements. Finally, it will extend the pump laser wavelength into near infrared, which will unlock the ability of the technique to use strong absorption lines for a range of widely available species (water, carbon dioxide and hydrocarbons), using industrial lasers at high repetition rates. The final outcome of the project will be the development of an instrument and method for non-intrusive temperature and species measurements in high temperature, high pressure practical reacting flows, requiring only a fraction of the cost of previous techniques of comparable precision. Demonstration measurements will be produced in a high pressure, high temperature, realistic industrial facility. Data produced during these measurements will also allow researchers and developers to review and validate robust reacting flow models for industry and open up the possibilities for optimisation of clean energy conversion devices. The plan for technology transfer is ensured by partnering with a company (Dantec) that has already packaged and commercialised similar instruments. An extension of the validation measurements to other industrial facilities at Rolls-Royce is planned once the instrument development and demonstration has been successfully concluded. Finally, the project will also offer opportunities to PhD students associated with the Energy CDT at Cardiff. |
| Exploitation Route | See parent grant held at Cambridge/Hochgreb (EP/T030801/1) for detail ........ 1/ Experimental database: the experimental data and the associated geometric and flow details for the measurements are being packaged for archival storage for use by CFD modellers interested in reproducing the results, along with other results obtained in different campaigns at Cardiff. 2/ Commercialisation: The plan is to attract a potential commercial partner (originally Dantec) to package the instrument as a turnkey platform for temperature measurements in high temperature high pressure environments. |
| Sectors | Aerospace Defence and Marine Energy |
| Description | See parent grant held at Cambridge/Hochgreb (EP/T030801/1) for detail ........ The measurement campaigns have now demonstrated the capability of the PILOT unit developed at Imperial/Oxford by Prof. B. Williams. Industrial users (Rolls-Royce) have now initiated contacts for use of the unit at the National Combustion Facilities at Loughborough. |
| First Year Of Impact | 2023 |
| Sector | Aerospace, Defence and Marine,Energy |
| Impact Types | Economic |
| Title | 2-axis traverse for improved optical diagnostics in reacting flow |
| Description | Addition of 2-axis traverse and staging to High Pressure Optical Combustion (HPOC) experimental rig at GTRC to allow for improved optical diagnostics setup, including line of sight methods such as that used in the LIGS technique. This proved essential in allowing for the movement of the LIGS measurement volume within the reacting flow, demonstrated in the accepted ASME paper "Spatial Temperature and Water Molar Concentration Measurements Using Thermal and Electrostrictive Ligs During Operation of a Swirl Burner at Pressure". |
| Type Of Material | Improvements to research infrastructure |
| Year Produced | 2023 |
| Provided To Others? | Yes |
| Impact | Accurate spatial measurements in high-pressure/temperature environments utilising optical diagnostic techniques (such as LIGS - the focus of this EPSRC award) |
| Title | Hi-Speed-Particle Imaging Velocimetry in GT combustors |
| Description | Commissioning of the high-speed PIV system on the HPOC experimental rig. For the LIGS project the high-speed diagnostic suite was used for the first time, obtaining flow field measurements within a representative gas turbine combustor for both isothermal and reacting flows. |
| Type Of Material | Improvements to research infrastructure |
| Year Produced | 2023 |
| Provided To Others? | No |
| Impact | Impacts to come - CFD validations, etc.. |
| Title | Optical Modular Combustor |
| Description | A new Optical Modular Combustor has been commissioned which allows for the testing and refinement of a broad range of combustion strategies for current and future alternative fuels. This new combustor integrates into the High Pressure Combustion Rig at the GTRC facility, and provides improved optical access for advanced diagnostic techniques. The modular nature allows the combustor to operate under Dry Low Emission or staged (such as Rich-Quench-Lean) configurations, at elevated temperature and pressure conditions. In addition to the development of the new combustor, a traversable optical platform has been added, which allows for 2D spatially resolved data to be obtained when using optical techniques such as that developed during the LIGS project. |
| Type Of Material | Improvements to research infrastructure |
| Year Produced | 2023 |
| Provided To Others? | Yes |
| Impact | The addition to the GTRC facility provides an additional test option for the study of combustion strategies for current and future alternative fuels. It has already been utilised on other UKRI projects such as IDRIC. |
| Description | Press release from Cardiff GTRC on preliminary LIGS experiments at the high pressure combustion facility |
| Form Of Engagement Activity | Engagement focused website, blog or social media channel |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | Laser Induced Grating Spectroscopy (LIGS) measurements taken at the @GTRC (includes video) https://www.linkedin.com/feed/update/ugcPost:69079 87131495788546 @GTRC hosted researchers @lweller2016 and @Priyav Shah from @Cambridge University and @Oxford University as part of an @EPSRC project "Tracer-free, non-intrusive, time- and space-resolved temperature and scalar measurements", Principal Investigator @Simone Hochgreb The need for low emission combustion technology requires an understanding of the local gas temperature. In-flame, non-intrusive temperature measurement in pressurised highly radiant flames typically requires complex optical techniques. LIGS is a non-linear laser optical diagnostic technique which can be used to measure the temperature, pressure or species concentration at a point. The technique uses a pulsed laser to create a laser-induced grating, and a continuous wave laser to measure the transient properties of the grating. LIGS is a robust option for challenging 'dirty' environments, excels at elevated pressures and is computationally inexpensive compared to similar diagnostics. (https://link.springer.com/article/10.1007/s00340- 003-1282-8) This test campaign showed that a LIGS signal could be measured in a 75kWth methane flame at 4bar. Future test campaigns aim to extend this to higher pressures and powers, and provide valuable experimental data to validate combustion models. #Netzero #Hydrogen #Industrial Decarbonisation #Emissions #Gas Turbines #Instrumentation |
| Year(s) Of Engagement Activity | 2022 |
| URL | https://www.linkedin.com/posts/cardiff-university-gas-turbine-research-centre_netzero-netzero2050-hy... |