Analysis and Design of a Steam Ejector Structure
By adjusting structures of the nozzle and mixing-chamber , effects of the structure on the steam ejector performance were analyzed. An improved CFD program which was proved suitable for simulating flow profile in a steam ejector formerly was used here. The results of this study would be useful for designing a steam ejector with high performance when working condition was given.
Analysis of ejector performance using dimensionless parameters
From the ample computational results,the relationships among maximum entrainment ratio,expansion ratio and critical compression ratio were concluded.A power correlation between expansion ratio and Mach number at the nozzle outlet was found.Using two dimensionless parameters,namely expansion ratio and critical compression ratio to replace actual motive fluid pressure — suction pressure and critical discharging pressure to analyze the effect of the operation parameters on the ejector performance,can make the results more universal and useful in ejector designing and ejector efficiency.
Ozonation of polycyclic aromatic hydrocarbons in oil/water-emulsions: mass transfer and reaction kinetics.
The ozonation of highly condensed polycyclic aromatic hydrocarbons (PAH) was studied in oil/water-emulsions, which are comparable to poorly water-soluble PAH in industrial wastewaters and at contaminated sites. As there was a lack of knowledge about the ozonation in oil/water-emulsions, first the ozone mass transfer was studied and optimized from the gas to the water phase and from the water to the oil phase. The ratio of mass transfer and oxidation reaction was determined by the Hatta-number and revealed a slow, quasi homogeneous reaction of ozone with PAH inside the oil droplets. Because the ozone gas concentration had no influence under the optimized conditions, the selective PAH-ozonation could be described microkinetically by a direct ozone reaction of pseudo-first order regarding PAH-concentrations. The determined PAH mean reaction rate constants of 1.02 min(-1) in oil/water-emulsions are in the upper range as found for PAH dissolved in water. These results give a new insight into the ozonation in the three-phase systems and into the treatment of highly condensed, hardly biodegradable PAH.