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New criterion for characterization of thermal-saline jets discharged from thermal desalination plants

Azadi, A ; Sharif University of Technology | 2022

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  1. Type of Document: Article
  2. DOI: 10.1016/j.ijheatmasstransfer.2022.123142
  3. Publisher: Elsevier Ltd , 2022
  4. Abstract:
  5. More than 80% of desalination plants use the multi-stage flash (MSF) technology in the Persian Gulf and hence may have a severe irreversible impact on the marine environment. In the present study, geometrical, mixing, and turbulence characteristics of thermal-saline jets, similar to MSF effluents, are numerically investigated using the dynamic Smagorinsky sub-grid scale (SGS) model and UNESCO equation of state. For this purpose, two affecting dimensionless parameters are considered: (1) density ratio, which is thermal flux to salinity flux ratio, and (2) salinity Froude number. Examining the effects of density ratio reveals that the jet flow pattern only depends on the density ratio with a separating range of 1.2-1.3. In addition, increasing the density ratio increases the geometrical values of descending jets, reduces the geometrical values of ascending ones, and increases the descending jet's dilution before returning to the bed. Furthermore, geometrical values of descending jets show asymptotic behavior for density ratios less than 0.7. Eventually, turbulence characteristics of different jet flow patterns show that large turbulence structures are more explicit for the quasi-neutral scenario. The current results recommend that thermal desalination discharges similar to quasi-neutral jets with density ratios in a range of 1.2-1.3 achieve better mixing characteristics. © 2022
  6. Keywords:
  7. Environmental impacts ; LES ; Numerical modeling ; Turbulence characteristic ; Desalination ; Equations of state ; Geometry ; Mixing ; Turbulence ; Density ratio ; Inclined jet ; Jetflows ; Mixing characteristics ; Multi stage flash ; Thermal ; Thermal desalination plant ; Thermal-saline jet ; Turbulence characteristics ; Flow patterns
  8. Source: International Journal of Heat and Mass Transfer ; Volume 195 , 2022 ; 00179310 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0017931022006135