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- Abou Nada, Fahed
(författare)
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Phosphor Thermometry: Advances in Technique Development and Applications
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Understanding the mechanisms that govern the combustion processes is important for being able to further increase the efficiency ofcombustion devices. Temperature is considered to be one of the most important parameters controlling the progression and finalproducts of combustion. Regulating the temperature in combustion devices enables higher degrees of efficiency to be achieved. Theengine components in combustion devices are subjected to high levels of thermal load. These can strain many of the engine componentsand if it is unattended to can lead to catastrophic engine failure. Temperature information can help to assess the thermal load the engineis experiencing and as a result can increase the longevity of the engine while at the same time enabling higher levels of efficiency to beattained. In addition, the production of emission gases is closely correlated to the temperature present during the combustion of fuel.Comprehending the spatial and temporal distribution of temperature can aid in finding measures to reduce the levels of emissiongenerated by a combustion engine.Although several different temperature-probing techniques that can provide temperature information are available, the harsh andreactive nature of the experimental conditions present within combustion engines can severely limit the applicability of such techniques.Phosphor thermometry excels in delivering precise and accurate temperature information concerning harsh environments such as thosepresent in combustion engines. It is a remote technique that is minimally intrusive and is highly robust. Phosphor thermometry utilizesthe temperature-dependent characteristic emission of thermographic phosphors to retrieve temperature information concerning asurface or a fluid. The temperatures can be determined either on the basis of the temperature dependence of the decay time of thephosphorescence or on the basis of temperature-dependent changes in the spectral distribution of the phosphorescence.The thesis presents the efforts that were made to develop the phosphor thermometry technique further. It involves demonstrations ofuse of this technique in combustion engines of different types. The results of the thesis work are reported in two major parts. In thefirst part, developments that were made in regard to certain fundamentals of the technique so as to improve its accuracy and precisionare documented. This includes the development of an automatic calibration routine, a more precise characterization of the detectorresponse, and investigation of the effects of engine lubricant oil on the performance of several different thermographic phosphors. Thesecond part of the thesis reports on several applications of phosphor thermometry technique to remote probing of the temperature ofdifferent motor components, such as the piston, the cylinder wall, and the burner tip of the combustor. The overall aim of the workconducted was to improve the precision and the accuracy of decay time-based phosphor thermometry as well as to enhance itsapplicability under a wider range of experimental conditions than studied previously.
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| 2. |
- Binder, Christian, 1988-, et al.
(författare)
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Heat Loss Analysis of a Steel Piston and a YSZ Coated Piston in a Heavy-Duty Diesel Engine Using Phosphor Thermometry Measurements
- 2017
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Ingår i: SAE International Journal of Engines. - : SAE International. - 1946-3936 .- 1946-3944. ; 10:4, s. 1954-1968
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Tidskriftsartikel (refereegranskat)abstract
- Diesel engine manufacturers strive towards further efficiency improvements. Thus, reducing in-cylinder heat losses is becoming increasingly important. Understanding how location, thermal insulation, and engine operating conditions affect the heattransfer to the combustion chamber walls is fundamental for the future reduction of in-cylinder heat losses. This study investigates the effect of a 1mm-thick plasma-sprayed yttria-stabilized zirconia (YSZ) coating on a piston. Such a coated piston and a similar steel piston are compared to each other based on experimental data for the heat release, the heat transfer rate to the oil in the piston cooling gallery, the local instantaneous surface temperature, and the local instantaneous surface heat flux. The surface temperature was measured for different crank angle positions using phosphor thermometry. The fuel was chosen to be n-heptane to facilitate surface temperature measurements during non-skip-fire, thermally stabilized operating conditions. Assuming one-dimensional heat transfer inside each piston, the local instantaneous surface heat flux was calculated using the heat transfer rate to the oil in the piston cooling gallery and the surface temperature measurements. The results from this study show that the surface temperature variation is similar for both pistons. The instantaneous heat flux during combustion is however significantly greater for the steel piston than the coated piston. The heat release analysis also indicates that combustion is slower for the piston with the yttria-stabilized zirconia coating.
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| 3. |
- Pfaff, Sebastian, et al.
(författare)
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Temperature characterization of an operando flow reactor for heterogeneous catalysis
- 2019
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Ingår i: Journal of Physics D: Applied Physics. - : IOP Publishing. - 0022-3727 .- 1361-6463. ; 52:32
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we present several methods to determine the temperature of a catalyst sample, as well as the gas surrounding it, in a typical flow reactor used for operando research on heterogeneous catalysis. To determine the sample temperature, we present an approach using calibrated IR-camera imagery, as well as thermographic phosphors. For the gas temperature, we present methods to extract temperature information from Planar Laser Induced Fluorescence (PLIF) measurements, one of which can be used during operando studies with an active catalyst in place.
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