| 1. |
- Aldén, Marcus, et al.
(författare)
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Laser-induced phosphorescence spectroscopy: development and application of thermographic phosphors (TP) for thermometry in combustion environments
- 2014
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Ingår i: Laser Spectroscopy for Sensing Fundamentals, Techniques and Applications. - : Elsevier. - 2050-1501. - 9780857092731 - 9780857098733 ; , s. 258-291
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Bokkapitel (refereegranskat)abstract
- In this chapter a temperature probing technique based on the spectroscopy of inorganic luminescent materials is described and exemplified in experiments related to combustion. The basic features of thermographic phosphors which enable remote temperature diagnostics to be performed with a high degree of sensitivity and accuracy, are outlined. This technique is superior to those based on thermocouples and pyrometry, particularly in the vicinity of flames and when the measured surface is subjected to random movements. Many thermographic phosphors have the property of being insensitive to variations in pressure up to 1 GPa. This property extends the use and development of thermographic thermometry to such domains as internal combustion engines and gas turbines, for which examples are also provided.
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| 2. |
- Aldén, Marcus, et al.
(författare)
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Thermographic phosphors for thermometry: A survey of combustion applications
- 2011
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Ingår i: Progress in Energy and Combustion Science. - : Elsevier BV. - 0360-1285. ; 37:4, s. 422-461
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Forskningsöversikt (refereegranskat)abstract
- Temperature is a fundamental thermodynamic parameter used to describe physical, chemical and biological processes. In combustion as in many other applications, knowledge about temperature plays a substantial role in helping to maintain an efficient and clean environment Being able to measure temperature accurately in combustion and in fire-related applications is important for giving a better understanding of heat transfer phenomena and improving existing models. In the present review paper a method based on the spectroscopy of inorganic luminescent materials is described and exemplified in experiments related to combustion. The method involves the use of thermographic phosphors which enable remote temperature diagnostics to be performed with a high degree of sensitivity and accuracy. The technique is superior to those based on thermocouples and pyrometry, particularly in the vicinity of flames and when the measured surface is subjected to random movements. Several phosphor materials suitable for temperature probing are described. The application of thermographic phosphors to temperature measurements in one-point and in two-dimensions in flame spread scenarios, and in pyrolysis experiments involving different construction materials and polymers are described. Many thermographic phosphors have the property of being insensitive to variations in pressure up to 1 GPa. This property extends the use and development of thermographic thermometry to other domains, such as internal combustion engines. The temperature has been measured in a point and in two-dimensions inside the combustion chamber. The complex procedures required to implement the use of thermocouples on moving objects inside an engine make thermocouples an expensive choice. It also limits the possibilities of altering the measurement locations and thereby also complicating the investigation of different engine geometries and components. Thermographic phosphors have also been employed in gas turbine applications. Temperature probing in the afterburner of a full-size aircraft engine is described with the aim to study the effects of various engine loads on the wall temperature. Furthermore, the application of thermographic phosphors to study the temperature of droplets in relation to sprays is described. In spray dynamics, temperature is a crucial parameter for gaining an understanding of atomisation, evaporation and heat convection from the surrounding gases. Finally the application of thermographic phosphors for gas temperature measurement by seeding the particles into a gas flow is described together with the challenges associated with seeding the particles for in-situ flame measurements. (C) 2010 Published by Elsevier Ltd.
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| 3. |
- Hildingsson, Leif, et al.
(författare)
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Simultaneous Formaldehyde and Fuel-Tracer LIF Imaging in a High-Speed Diesel Engine With Optically Accessible Realistic Combustion Chamber
- 2005
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Ingår i: SAE Technical Paper Series. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191.
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Konferensbidrag (refereegranskat)abstract
- Simultaneous laser-induced fluorescence (LIF) imaging of formaldehyde and a fuel-tracer have been performed in a high-speed diesel engine. N-heptane and isooctane were used as fuel and toluene was used as a tracer. This arrangement made it possible to make simultaneous measurements of toluene by exciting at 266 nm and detecting at 270-320 nm while exciting formaldehyde at 355 nm and detecting at 400-500 nm.The aim of this study is to investigate how traditional fuel tracer and natural-occurring formaldehyde formed in the cool chemistry are transported in the piston bowl. A range of ignition delays were created by running the engine with different amounts of EGR. During this sweep the area where the low-temperature reactions take place were studied.The measurements were performed in a 0.5-l, single-cylinder optical engine running under conditions simulating a cruise-point, i.e., about 2.2 bar imep. The ignition delay was elongated compared to the normal mapping and the engine-out emissions of soot and NOx were ultra-low.It was found that the spatial location of LTR's does not shift significantly for different EGR levels. The formaldehyde signal overlaps the fuel signal in most cases before the onset of the main heat release.
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| 4. |
- Omrane, Alaa, et al.
(författare)
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2D-temperature imaging of single droplets and sprays using thermographic phosphors
- 2004
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Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171 .- 1432-0649. ; 79:4, s. 431-434
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Tidskriftsartikel (refereegranskat)abstract
- A novel 2D-technique for temperature visualization of single droplets and sprays is presented. Laser induced emission from thermographic phosphor seeded to the investigated liquid was detected by a fast framing camera. The subsequent phosphorescence images measured by seven consecutively gated CCD detectors allowed pixel-to-pixel lifetime evaluation of the phosphorescence emission. The temperature at each pixel position was evaluated using a calibration procedure of temperature against lifetime. These measurements were applied first to a free falling water based droplet, then to a suspended droplet in an ultrasonic levitator. Finally, the technique was applied to spray.
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| 5. |
- Remie, Martin, et al.
(författare)
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Extended heat-transfer relation for an impinging laminar flame jet to a flat plate
- 2008
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Ingår i: International Journal of Heat and Mass Transfer. - : Elsevier BV. - 0017-9310. ; 51:7-8, s. 1854-1865
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Tidskriftsartikel (refereegranskat)abstract
- Many industrial applications use flame impingement to obtain high heat-transfer rates. An analytical expression for the convective part of the heat transfer of a flame jet to a plate is derived. Therefore, the flame jet is approximated by a hot inert jet. In contradiction with existing convective heat-transfer relations, our analytical solution is applicable not only for large distances between the jet and the plate, but also for close spacings. Multiplying the convective heat transfer by a factor which takes chemical recombination in the cold boundary layer into account, results in an expression for the heat flux from a flame jet to the hot spot of a heated plate. Numerical and experimental validation show good agreement.
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| 6. |
- Remie, Martin, et al.
(författare)
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Heat-transfer distribution for an impinging laminar flame jet to a flat plate
- 2008
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Ingår i: International Journal of Heat and Mass Transfer. - : Elsevier BV. - 0017-9310. ; 51:11-12, s. 3144-3152
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Tidskriftsartikel (refereegranskat)abstract
- Impinging flame jets are widely used in applications where high heat-transfer rates are needed, for instance in the glass industry. During the heating process of glass products, internal thermal stresses develop in the material due to temperature gradients. In order to avoid excessive thermal gradients as well as overheating of the hot spots, it is important to know and control the temperature distribution inside a heated glass product. Therefore, it is advantageous to know the relation describing the convective heat–flux distribution at the heated side of a glass product. In a previous work, we presented a heat–flux relation applicable for the hot spot of the target [M.J. Remie, G. Sa¨rner, M.F.G. Cremers, A. Omrane, K.R.A.M. Schreel, M. Alde´n, L.P.H. de Goey, Extended heat-transfer relation for an impinging laminar flame jet to a flat plate, Int. J. Heat Mass Transfer, in press]. In this paper, we present an extension of this relation, which is applicable for larger radial distances from the hot spot.
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| 7. |
- Seyfried, Hans, et al.
(författare)
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Optical diagnostics for characterization of a full-size fighter-jet afterburner
- 2005
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Ingår i: Proceedings of the ASME Turbo Expo 2005. - 9780791846995 ; 1, s. 813-819
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Konferensbidrag (refereegranskat)abstract
- In the present work the feasibility of using various optical/laser based techniques for characterization of the afterburner of a full-size aircraft engine have been investigated. The tests have been performed on-site at Volvo Aero Corporation and were mainly directed towards surface thermometry using thermographic phosphors and fuel visualization. All applications were studied for different engine running conditions, including various use of the afterburner (A/B). Laser-Induced Fluorescence (LIF) was employed for fuel visualization to investigate to what extent unburned fuel exits the afterburner. Laser-Induced Phosphorescence (LIP) from thermographic phosphors was used to measure two-dimensional surface temperatures on the outlet nozzle of the afterburner. In addition, the spectral characteristics of the burning jet stream were investigated. Copyright
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| 8. |
- Särner, Gustaf, et al.
(författare)
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Cycle Resolved Wall Temperature Measurements Using Laser-Induced Phosphorescence in an HCCI Engine
- 2005
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Ingår i: SAE technical paper series.
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Tidskriftsartikel (refereegranskat)abstract
- Cycle-resolved wall temperature measurements have been performed in a one-cylinder, port-injected optical Scania D12 truck engine run in HCCI mode. Point measurements at various locations were made using Laser-Induced Phosphorescence (LIP). Single point measurements with thermographic phosphors utilize the temperature dependency of the phosphorescence decay time. The phosphorescence peak at 538 nm from the thermographic phosphor La2O2S:Eu was used to determine temperature. A frequency tripled 10 Hz pulsed Nd:YAG laser delivering ultraviolet (UV) radiation at 355 nm was used for excitation of the phosphor. Detection in the spectral region 535 - 545 nm was performed every cycle with a photo multiplier tube connected to a 3 GHz oscilloscope. Measurements were made at four points on the cylinder head surface and two points on the outlet and inlet valves respectively. For each location measurements were made at different loads and at different crank angle degrees (CAD). The aim of the presented work was to study the feasibility of using LIP for single-shot, cycle-resolved wall temperature measurements.
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| 9. |
- Särner, Gustaf, et al.
(författare)
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Investigations of blue emitting phosphors for thermometry
- 2008
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Ingår i: Measurement Science & Technology. - : IOP Publishing. - 0957-0233 .- 1361-6501. ; 19:12
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Tidskriftsartikel (refereegranskat)abstract
- Blue emitting phosphors are investigated and reported for possible use in thermometry. Currently reported thermographic phosphors in general have the drawback of long emission lifetimes obstructing the possibility to time gate for background discrimination. An additional problem is that many thermographic phosphors have emission in the red spectral region, making them vulnerable for black body radiation at high temperatures. This work reports the temperature sensitivity for nine phosphors considered suitable for accurate temperature measurements in harsh conditions both in single points and in two dimensions (2D).
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| 10. |
- Särner, Gustaf
(författare)
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Laser-Induced Emission Techniques for Concentration and Temperature Probing in Combustion
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The work in this thesis is aimed at the development of temperature and gas concentration measurement techniques in laser diagnostics for use in combustion research. The techniques are developed as tools for the combustion community to meet future demands on combustion efficiency and legislation of exhaust gases. Thermometry based on the use of laser-induced phosphorescence has been further developed and performed inside internal combustion engines, in a gas turbine afterburner, in burning liquids, and in research on oxy-fuel flame heat transfer. In work carried out within the EU 6:th framework program, an attempt was made to find new suitable thermographic phosphors for high temperature two-dimensional measurements in gas turbines. The gas turbine industry has a strong interest in better methods of thermometry at high temperatures for optimizing performance of combustion and engine parts. Measurements on spinning objects require the use of fast phosphors, previously unavailable for high-temperature two-dimensional measurements. A variety of inorganic phosphor materials, not previously used in thermometry, were investigated, some of them being very promising for thermographic use. Laser-induced oxygen sensing using a commercial pressure sensitive paint has been applied in low-temperature combustion. The material has been calibrated to oxygen and temperature. The work show on the potential of using oxygen quenched materials in combustion research even though it involves organic sensing materials. Laser-Induced Fluorescence was employed for visualization of formaldehyde both in Homogeneous Charge Compression Ignition, HCCI, and in Diesel combustion engines. Formaldehyde formed in HCCI combustion during low temperature reactions was shown to be able to function as fuel marker. This was demonstrated in simultaneous visualization of the traditional fuel tracer toluene and formaldehyde during operation of an HCCI engine. The use of formaldehyde as a fuel marker was also demonstrated in Diesel combustion, which is characterized by a lack of low temperature reactions and where the location of intermediate species is not obvious. Fuel visualization was also employed for the visualization of jet fuel in a jet stream of a fighter-jet gas turbine. Un-burnt fuel was found to exist in the exhaust for some engine conditions.
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