Loading...
Please wait, while we are loading the content...
Similar Documents
Characterization of fluorescent polystyrene microspheres for advanced flow diagnostics
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Danley, Jason E. Tiemsin, Pacita Koh, Brian Byun, Guibo Danehy, Paul M. Lowe, K. Todd Maisto, Pietro M. F. Wohl, Christopher J. Vercamp, Max Simpson, Roger |
| Copyright Year | 2013 |
| Description | Fluorescent dye-doped polystyrene latex microspheres (PSLs) are being developed for velocimetry and scalar measurements in variable property flows. Two organic dyes, Rhodamine B (RhB) and dichlorofluorescence (DCF), are examined to assess laser-induced fluorescence (LIF) properties for flow imaging applications and single-shot temperature measurements. A major interest in the current research is the application of safe dyes, thus DCF is of particular interest, while RhB is used as a benchmark. Success is demonstrated for single-point laser Doppler velocimetry (LDV) and also imaging fluorescence, excited via a continuous wave 2 W laser beam, for exposures down to 10 ms. In contrast, when exciting with a pulsed Nd:YAG laser at 200 mJ/pulse, no fluorescence was detected, even when integrating tens of pulses. We show that this is due to saturation of the LIF signal at relatively low excitation intensities, 4-5 orders of magnitude lower than the pulsed laser intensity. A two-band LIF technique is applied in a heated jet, indicating that the technique effectively removes interfering inputs such as particle diameter variation. Temperature measurement uncertainties are estimated based upon the variance measured for the two-band LIF intensity ratio and the achievable dye temperature sensitivity, indicating that particles developed to date may provide about +/-12.5 C precision, while future improvements in dye temperature sensitivity and signal quality may enable single-shot temperature measurements with sub-degree precision. |
| File Size | 1249758 |
| Page Count | 15 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20140000482 |
| Archival Resource Key | ark:/13960/t0bw2gd56 |
| Language | English |
| Publisher Date | 2013-06-24 |
| Access Restriction | Open |
| Subject Keyword | Temperature Measurement Rhodamine Dyes Laser Doppler Velocimeters Temperature Effects Laser Induced Fluorescence Imaging Techniques Flow Visualization Scalars Velocity Measurement Continuous Wave Lasers Microparticles Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
