Droplet-Laden Homogeneous Turbulent Flow Over Unheated and Heated Cylinders

Published

February 1, 2003

Author(s)

Cary Presser, G Papadopoulos, J F. Widmann

Abstract

The dispersal of high boiling point liquid fire suppression agents around solid obstacles is investigated to obtain a better understanding of the physical processes of droplet transport in cluttered spaces. To this end, the present experimental investigation examines the flow field dynamics of grid-generated homogeneous turbulent flow over obstacles, and spray transport in such flow fields. Transport of both water droplets and aerosol particles was characterized upstream and downstream of a cylinder using particle image velocimetry (PIV). Data were obtained for the cylinder at ambient temperature and after being heated to 423 K to estimate the effects of the hot cylinder surface on droplet transport.The results indicate that smaller droplets are entrained into the recirculation region behind the cylinder while the larger droplets impact the cylinder surface, accumulate and drip off, or disperse away from the surface. The flow over the heated cylinder indicates the formation of a vapor layer on the downstream side of the cylinder in the shear region between the recirculation zone and free stream. Thus, vaporization of smaller droplets near the heated cylinder surface suggests an increased probability of vapor, and reduced probability of droplet entrainment into cylinder wake region.

Citation

ASME/JSME Joint Fluids Engineering Conference

Pub Type

Journals

Keywords

computational fluid dynamics, droplet/particle transport, fire suppression, halon alternatives, homogeneous turbulent flow, model validation, particle image velocimetry

Citation

Presser, C. , Papadopoulos, G. and Widmann, J. (2003), Droplet-Laden Homogeneous Turbulent Flow Over Unheated and Heated Cylinders, ASME/JSME Joint Fluids Engineering Conference (Accessed April 24, 2024)