Hydrodynamics of the steam-water two-phase flows behind a pair of bluff cylinderical bodies inside and around the wake region

Abstract

A significant number of natural and industrial phenomena exist, where steam-water, two-phase flows face resistance due to the cylindrical shaped bodies. It is useful to explore such flows for their direct relevance to the steam driven industrial processes having Direct Contact Condensation (DCC) as the core phenomena for heat, mass, and momentum transfer. An experimental setup has been fabricated to study the influence of twin, different sized cylinders with a gap between them on the formation of wake region as the steam-water flow past the cylinders. Hot and cold wire sensors were used to measure the fluctuations in the velocity and temperature respectively of the flow within the wake and the region surrounding wake. The diameter of the smaller cylinder was fixed as 0.5 cm and the dimensions of the larger cylinder was varied from 1, 1.5 and 2.0 cm. Values for the fluctuating velocity were measure for all the cases and based on these measurements, the turbulent normal stresses and Reynolds shear stresses were determined. The asymmetry of the wake region increases by raising the gap between the two cylinders as the wake region aligned to the smaller cylinder has been deflected larger than the wake aligned to the larger cylinder. The wake asymmetry signified the possible effect of buoyancy on the thermal and momentum diffusivities, which was emphasized here through the measured values of turbulent normal and Reynolds stresses.