Experimental Investigation of Inner Nozzle Surface Modifications on the Flow Regimes in Steam/Water Flow

Abstract

Mixing of two phase flows can be enhanced by modifying the inner surface of gas/vapor injection chamber. In the present study, we perform experimental PIV investigation focusing the planar region across the supersonic steam jet injection into the water in a transparent rectangular duct 4 ft high. Axial pressure profile of the rectangular channel is obtained to highlight the impact of inner surface modifications of supersonic nozzle on the steam-water interfacial hydrodynamics for inlet pressure ranging between 1.5 and 3.0 bars. Results show elongation of the vortical structures with increase in pressure. The profile of the spatial scalar fluctuations intensity decreases with peaks at certain locations indicating formation of shocks within the steam jet in the upstream region. Turbulence induced mixing is observed as the interfacial structure breaks down causing local minima. However, due to the inner surface modifications the local minima shifted from the nozzle’s exit up to 1.7% lengthwise than the smooth inner surface. The intensity of high pressure locations are found to be vary between 4 and 5% along the flow channel. However, due to the inner surface modifications, the lengths of the high pressure crests reduced by 3.4–5.2%.