# Temperature field measurements in liquids using ZnO thermographic phosphor tracer particles

Temperature field measurements in liquids using ZnO thermographic phosphor tracer particles Temperature field measurements in liquids are demonstrated using zinc oxide (ZnO) thermographic phosphor particles. The particles are added to the liquid as a tracer. Following laser excitation, the temperature-dependent luminescence emission of the particles is imaged and the temperature is determined using a two-colour intensity ratio method. The particle size requirements for accurate temperature tracing in turbulent flows are calculated using a numerical heat transfer model. Particle–water mixtures were prepared using ultrasonic dispersion and characterised using scanning electron microscope imaging and laser diffraction particle-sizing, indicating that the particle size is 1–2  $$\upmu$$ μ m. The particle luminescence properties were characterised using spectroscopic and particle luminescence imaging techniques. Using 355 nm laser excitation, the luminescence signal is the same in water and in air. However, 266 nm excitation is used to avoid spectral overlap between Raman scattering from water and the detected ZnO luminescence emission. It is shown that 266 nm excitation can be used for temperature measurements in water using mass loads as low as 1–5 mg L $$^{-1}$$ - 1 , corresponding to measured particle number densities 0.5–2.5  $$\times \,10^{12}$$ × 10 12 particles  $$\hbox {m}^{-3}$$ m - 3 . In this range, the measured intensity ratio is independent of the mass load. The dependence of the intensity ratio on the laser fluence is less pronounced using excitation at 266 nm compared to 355 nm. A single-shot, single-pixel temperature precision of ±2–3  $$^{\circ }\hbox {C}\,(1\sigma )$$ ∘ C ( 1 σ ) can be achieved over a temperature range spanning $$50\,^{\circ }\hbox {C}$$ 50 ∘ C . The technique was applied to a convection experiment to measure the temperature fields in a buoyant thermal plume, demonstrating the suitability of these imaging diagnostics for the investigation of thermal convection and heat transfer. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Experiments in Fluids Springer Journals

# Temperature field measurements in liquids using ZnO thermographic phosphor tracer particles

, Volume 57 (7) – Jun 22, 2016
14 pages

/lp/springer_journal/temperature-field-measurements-in-liquids-using-zno-thermographic-BJyx17aMSo
Publisher
Springer Berlin Heidelberg
Subject
Engineering; Engineering Fluid Dynamics; Fluid- and Aerodynamics; Engineering Thermodynamics, Heat and Mass Transfer
ISSN
0723-4864
eISSN
1432-1114
D.O.I.
10.1007/s00348-016-2200-2
Publisher site
See Article on Publisher Site

## You’re reading a free preview. Subscribe to read the entire article.

### DeepDyve is your personal research library

It’s your single place to instantly
that matters to you.

over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $49/month ### Explore the DeepDyve Library ### Unlimited reading Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere. ### Stay up to date Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates. ### Organize your research It’s easy to organize your research with our built-in tools. ### Your journals are on DeepDyve Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more. All the latest content is available, no embargo periods. ### Monthly Plan • Read unlimited articles • Personalized recommendations • No expiration • Print 20 pages per month • 20% off on PDF purchases • Organize your research • Get updates on your journals and topic searches$49/month

14-day Free Trial

Best Deal — 39% off

### Annual Plan

• All the features of the Professional Plan, but for 39% off!
• Billed annually
• No expiration
• For the normal price of 10 articles elsewhere, you get one full year of unlimited access to articles.

$588$360/year

billed annually

14-day Free Trial