High-speed planar thermometry and velocimetry using thermographic phosphor particles

Abstract

Simultaneous gas-phase temperature and velocity imaging using micrometer-size thermographic phosphor particles seeded into the flow is demonstrated at a 3 kHz repetition rate. The velocity field is measured using a standard particle image velocimetry approach, while the temperature is determined from the temperature sensitive phosphorescence emission of the particles following excitation at 355 nm. Since the particles are very small, they rapidly assume the temperature and velocity of the surrounding gas. A single shot temperature precision of better than 5 % was achieved at 500 K. Time-resolved measurements in the wake of a heated cylinder are presented, demonstrating the utility of these imaging diagnostics to observe transient, coupled heat and mass transfer phenomena.

Planar measurements of spray-induced wall cooling using phosphor thermometry

“…This is the reason why this approach was particularly suitable for fluid flow temperature field measurements allowing also the possibility of simultaneous velocity field measurements as demonstrated by Fond et al (2012) at 10 Hz and Abram et al (2013) at multi-kHz repetition rates. Its potential for precise surface thermometry has been reported by other researchers.…”

Characterisation of the luminescence properties of BAM:Eu2+ particles as a tracer for thermographic particle image velocimetry

“…The principle of this thermographic PIV technique has been demonstrated for time-averaged [2] and single-shot measurements [1,3,4] as well as at kHz rates for temporally resolved measurements [5]. A similar concept called thermographic laser Doppler velocimetry was also demonstrated for point-wise measurements with high spatial resolution using continuous wave lasers and photomultiplier tubes [6].…”

“…In recent years, there have been several studies using thermographic phosphors for gas thermometry [1][2][3][4][5][6][7][8][9][10][11][12][13], and different phosphors have been used. Some important luminescence properties of these phosphors are indicated in Table 1.…”

“…These factors suggest that BAM:Eu 2+ is a promising phosphor, and indeed it has been successfully used for precise temperature measurements. It was even employed for measurements at kHz rate, using a diode-pumped solidstate laser, despite the low pulse energy (~1 mJ) offered by these lasers [5].…”

Fiber optic distributed temperature sensor mapping of a jet-mixing flow field

“…For liquids, dissolved fluorescent dyes have been employed in temperature mapping of single phase liquids (Dahikar et al 2010) and the two-phase field of a solidification process (Shafii et al 2010). Simultaneous PIV and LIF can be accomplished with thermochromic liquid crystal tracers (Dabiri 2009) and luminescent particles for liquid flow (Someya et al 2009) and gas flow (Abram et al 2013). These are powerful measurement methods, but chemicals must be added to flows and calibration is more elaborate than for PIV.…”