A NEW APPROACH TO INCREASING THE PERFORMANCE OF INITIAL DILUTION IN THERMAL WASTEWATER OUTFALLS: NOZZLE DOWNWARD INCLINATION METHOD

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Özdoğan Cumalı B., Çobanoğlu Kayıkçı C. B., Nemlioğlu S.

5TH INTERNATIONAL CONGRESS ON LIFE, SOCIAL, AND HEALTH SCIENCES IN A CHANGING WORLD, İstanbul, Türkiye, 26 - 27 Mart 2022, ss.209-214, (Tam Metin Bildiri)

  • Yayın Türü: Bildiri / Tam Metin Bildiri
  • Basıldığı Şehir: İstanbul
  • Basıldığı Ülke: Türkiye
  • Sayfa Sayıları: ss.209-214
  • İstanbul Üniversitesi-Cerrahpaşa Adresli: Evet

Özet

The cooling water of many thermal power plants located on the coast is provided by open-cycle sea water systems. Cooling waters discharged to the sea as heated from these systems may cause thermal pollution. Cooling waters discharged into the waterbody by power plants may cause the temperature of the receiving water body to increase and disrupt the ecological balance. Thermal wastewater outfalls with single-port or multi-port having diffusers can be widely used to reduce the level of thermal pollution to an acceptable level by forming jets from submerged discharge ports and dilution with rapid mixing. It is possible to increase the initial dilution capacity of thermal wastewater outfalls under suitable conditions. In this study, it was investigated to increase the initial dilution of a thermal wastewater sea outfall with a single horizontal circular nozzle to the stagnant and unstratified receiving water, at the impact point on the seawater surface, by the discharge nozzle downward inclination method. The dilutions of positively buoyant jets were calculated with the UM3 (Updated Merge) model of the Visual Plumes-VP program developed by the US Environmental Protection Agency (USEPA). Within the scope of the study, the initial temperature difference is +10°C, the receiving waterbody density is 1025 kg/m3, and the densimetric Froude number is 20 in VP-UM3. The diameter of nozzle is 0.3m and the discharge depths are 10m, 20m, 30m, 40m and 50m. For each condition, the impact point dilution values ​​for the horizontal state of the nozzle (0°) were determined separately, then the downward inclination angle was applied in the range of 1° to 35° and the dilution changes at the impact points were calculated. In the investigated discharge depth range (10m-50m), an average of 2% impact point dilution increase rate was achieved at an average 14° downward inclination angle. It has been found that the maximum dilution increase rate is approximately 4% and can be achieved at a 17° downward inclination angle for a discharge depth of 10m.