Flow characterization near the nozzle exit of the supersonic steam jet injecting into the stagnant water

الملخص EN

There has been a large amount of work being conducted on the thermo-dynamics of the direct contact condensation (DCC), however, not much attention was given to the phenomena particularly active near the steam’s nozzle exit.

a transparent rectangular upright duct of 4 ft high, was built with a supersonic nozzle positioned at the bottom of the channel to characterize flow behavior near the steam nozzle’s exit.

particle image velocimetry (PIV) was applied to draw information on the steam’s jet penetration into the water as well as the entrainment and mixing between the two phases under the steam’s inlet pressure ranging from 1.5 – 3.0 bars.

PIV normalized contour measurements depicted not appreciable changes in the radial velocity of the jet.

Whereas, in the core region of the jet, the change in the jet’s velocity was not much till Y/De ~ 4.3 and the vertical velocity of the jet decreased slowly till Y/De ~ 8.

the jet’s normalized upward velocity attained an optimized value between Y/De ~ 8 and Y/De ~ 9.8.

With varying pressures, 1.5 bars to 3.0 bars, the jet expanded radially in water.

It was also found in the near nozzle exit region, the shear layer’s thickness remained within 0.2 – 0.5 De over the 1.5 – 3.0 bars pressure.

probability density function (PDF) analysis of reynolds shear and normal stresses confirmed the existence of the velocity fluctuations across the shear layer, owing to the large eddies across the steam-water interface.