Temperature measurement techniques for gas and liquid flows using thermographic phosphor tracer particles

Christopher Abram

(Marie Curie Fellow, Princeton University)

 

时间：2017年9月27日（周三）下午2:30

地点：中国科学院力学研究所1号楼312会议室

Abstract

The development of advanced optical techniques for measuring fluid temperatures remains a key priority. This is especially true for flows involving heat transfer and/or chemical reactions, which are intrinsic to areas including energy production, the process industries, transportation, heating/cooling systems and in naturally-occurring thermal convection. Since these flows are most often turbulent, kHz sampling rates, fine spatial resolution and especially simultaneous velocity measurements are also necessary.

This talk is about fluid thermometry techniques that are based on thermographic phosphors, which are materials that possess temperature-dependent luminescence properties. Phosphor particles are seeded into the fluid flow of interest. Following laser excitation, the luminescence of the particles is detected, and the temperature measurement is derived using either the spectral intensity ratio or the lifetime. The same particles can also be used for velocity measurements using well-established particle-based approaches, such as Laser Doppler velocimetry (LDV) or particle image velocimetry (PIV), thereby producing instantaneously correlated vector-scalar data necessary to characterise turbulent flows. The various realisations of this basic concept are currently capable of point and two-dimensional temperature measurements over a broad temperature range, with a high level of precision and spatial/temporal resolution.

The talk will include (1) a brief outline of gas/liquid thermometry techniques; (2) a short description of thermographic phosphors and principles of the thermometry method; (3) a summary of our work on the characterisation of phosphor particles; (4) examples of recent developments toward improved precision and temporal/spatial resolution; (5) some current applications of the technique at kHz repetition rates in collaboration with other research groups, including gas turbine film cooling and expansion cooling; (6) perspectives on future advancements of these optical diagnostics.

Biography

Dr. Chris Abram is currently a Marie Curie Fellow at the Princeton University, USA. He obtained his MEng from University of Bristol, UK specialized in free convection in particle laden fluids. He obtained his Ph.D. degree from Imperial College London, UK on fluid thermometry using thermographic phosphor particles and commercialized his work in collaboration with LaVision. He conducted his postdoc research in Lehrstuhl für Technische Thermodynamik, Institut für Strömungstechnik und Thermodynamik, Otto-von-Guericke-Universität Magdeburg, Germany. His research interest is temperature measurement techniques for gas and liquid flows. Recently he is working on nanoparticle combustion synthesis methods.