Gas-phase thermometry in a high-pressure cell using BaMgAl 10 O 17 :Eu as a thermographic phosphor
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Gas-phase thermometry in a high-pressure cell using BaMgAl10O17:Eu as a thermographic phosphor J. P. J. van Lipzig • M. Yu • N. J. Dam C. C. M. Luijten • L. P. H. de Goey
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Received: 12 July 2012 / Accepted: 30 January 2013 / Published online: 17 April 2013 Springer-Verlag Berlin Heidelberg 2013
Abstract We demonstrate the feasibility of laser-induced phosphorescence thermography for gas-phase temperature field measurement in a high-pressure cell. BaMgAl10O17:Eu (BAM) was used as a thermographic phosphor; it shows a blue-shifted laser-induced emission spectrum with increasing temperature. Local temperature was determined from the intensity ratio of two disjunctive emission bands. A new seeding device was developed to suspend the solid thermographic phosphor particles in a gas environment. The particle suspension time was modeled and validated by experiments. The influence of multiple scattering and other aspects of quantitative measurement were examined. The technique is currently capable of measuring up to 650 K, limited by signal intensity. The 2D temperature distributions were measured with a precision better than 60 K at 650 K. Multiple scattering limits the spatial resolution to only about 10 mm along the line of sight.
1 Introduction Ongoing development of advanced optical diagnostics to measure temperature distributions non-intrusively is of great importance to advanced combustion engine research. For example, the temperature distribution of the gas mixture prior to fuel injection is an important parameter in understanding the role of temperature stratification during
J. P. J. van Lipzig M. Yu (&) N. J. Dam C. C. M. Luijten L. P. H. de Goey Section of Combustion Technology, Department of Mechanical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands e-mail: [email protected]
premixed charge compression ignition (PCCI) combustion. In PCCI [1, 2], a positive time delay exists between end of injection and start of combustion, which results in lower emissions due to better mixing of fuel and air. In our group, an optically accessible constant-volume highpressure cell (HPC) [3] is used to investigate fuel sprays under engine-like conditions, including those representative for PCCI. The mass-averaged temperature of the gas inside the HPC can be computed accurately from the measured pressure using the ideal gas law, however, determining local temperatures non-intrusively is more of a challenge. Laser-induced phosphorescence (LIP) is a promising technique to determine the 2D temperature fields in the gas phase. The method is based on electronically exciting a thermographic phosphor (TP) with laser radiation. During the relaxation, the TP emits radiation with a spectrum that changes with temperature (see Fig. 1) [4]. From the intensity ratio of two disjunct emission bands the temperature can be determined using a separately determined ratio–temperature calibration. The spectral bands used in our experiments are indicated by grey shading in Fig. 1. By using appropr
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