Thermophoretic Effects on Seeding Particles in LDV Measurements of Flames

Abstract

The motion of LDV seeding particles under the influence of viscous and thermophoretic forces in the rapidly-accelerating, high-temperature-gradient flame environment was studied via the counterflow premixed twin-flame configuration. Results demonstrate that thermophoretic force can induce significant lag between the fluid and.particle velocities in the active preheat zone of a flame, and suggest that caution should be exercised when interpreting LDV data obtained in this region. A thermophoretic velocity correction to the LDV-determined velocity, with known experimental or computational temperature profile, is proposed. Additional considerations of LDV diagnostics and its determination of laminar flame speed are also presented. © 1994, Taylor & Francis Group, LLC. All rights reserved.