Volumetric velocimetry for micron-scale seeding tracers in large volumes

Abstract

This paper presents the volumetric velocity measurement method of small seeding tracer with diameter $5\,\mathrm{\mu m}\sim 100\,\mathrm{\mu m}$ for volume $\geq 500\,\mathrm{cm}^3$. The size of seeding tracer is between helium-filled soap bobbles (HFSB) and di-ethyl-hexyl-sebacic acid ester(DEHS) droplets. The targeted measurement volume dimension equal to the volume of HFSB seeding, which will give a higher resolution of turbulence study. The relations between particle size, imaging and light intensity are formulated. The estimation of the imaging result are computed for the setup design. Finally, the methodology is demonstrated for turbulence velocity measurements in the jet flow, in which the velocities of averaged diameter $15 \,\mathrm{\mu m}$ air filled soap bubbles are measured in the volume of $\geq 2000\,\mathrm{cm}^3$ and $\geq 9000\,\mathrm{cm}^3$. This paper presents the volumetric velocity measurement method of small seeding tracer with diameter $5\,\mathrm{\mu m}\sim 100\,\mathrm{\mu m}$ for volume $\geq 500\,\mathrm{cm}^3$. The size of seeding tracer is between helium-filled soap bobbles (HFSB) and di-ethyl-hexyl-sebacic acid ester(DEHS) droplets. The targeted measurement volume dimension equal to the volume of HFSB seeding, which will give a higher resolution of turbulence study. The relations between particle size, imaging and light intensity are formulated. The estimation of the imaging result are computed for the setup design. Finally, the methodology is demonstrated for turbulence velocity measurements in the jet flow, in which the velocities of averaged diameter $15 \,\mathrm{\mu m}$ air filled soap bubbles are measured in the volume of $\geq 2000\,\mathrm{cm}^3$ and $\geq 9000\,\mathrm{cm}^3$.