Simulation-based verification of evaporation efficiency for an air carrier discharge with purified tritium-containing wastewater using high pressure spray technology
Objective To confirm the transportation and evaporation efficiency of micro droplets sprayed by high-pressure nozzles from purified tritium-containing wastewater with carrier gas in the horizontal evaporation chamber.Methods A scale test bench with a single high-pressure nozzle had been built based on design conditions and similarity criteria to explore the designed evaporation characteristics of generated micro droplets in the horizontal evaporation chamber.At the same time,combined with experimental data,a suitable evaporation model was constructed using the Discrete Phase Model(DPM)in Ansys Fluent.On this basis,further simulation and analysis were conducted on the evaporation process and efficiency under the condition of multiple nozzles in the desighed horizontal evaporation chamber.Results For single nozzle tests,the particle size of micro droplets along the nozzle centerline was between 12-50 μm and the particle size distribution was similar to the Rosin-Rammler distribution.Besides,the relative light intensity decreased exponentially with distance,indicating that the particle size and concentration of micro droplets both decreased rapidly,which means the evaporation rate of micro droplets was rapid.For the simulation of multiple nozzles injection in the desighed horizontal evaporation chamber,even for the hardest design condition,the evaporation percentage reached up to 99％,and small amount of the escaping micro droplets continued to evaporate during the process of mixing with other process exhaust until complete evaporation in the vertical chimney section.Conclusions Under the conditions of desighed sprayed particle size distribution,typical operating conditions and the incoming flow similar to the supposed area,the complete evaporation of the micro droplets can be basically achieved in the horizontal evaporation chamber,so as to ensure the complete evaporation of purified tritium-containing wastewater from the outlet of the chimney.
Nuclear facilitiesTritiumDischarge based on spray carriersElevated dischargeAirborne effluent
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