COMPARATIVE MULTIPHASE FLOW ANALYSIS OF DRY AND WET MARINE EXHAUST SYSTEMS BASED ON THERMAL, PRESSURE AND TURBULENCE CHARACTERISTICS

Year 2025, Volume: 1 Issue: 1, 21 - 28, 09.09.2025

Yasin Furkan Görgülü , Selcuk Ekici , Tahir Hikmet Karakoç

Abstract

This study employs CFD to compare dry and wet marine exhaust systems under identical conditions: a 15 m/s exhaust velocity at 470 °C and a 125 mm pipe. The dry exhaust, discharging into air, forms a buoyant plume extending approximately five pipe diameters with temperatures exceeding 200 °C downstream. Jet velocity remains above 5 m/s at 4D, and turbulence kinetic energy decreases by ~30% over the same distance. In contrast, the wet exhaust submerged in seawater cools below 60 °C within 2D, and jet velocity drops under 2 m/s by 1.5D. A localized static pressure rise of +12 kPa at the outlet is observed, approximately 100 times greater than the <0.12 kPa disturbance in the dry case. Turbulence decays by ~80% within 2D downstream of the wet exit. Dry exhaust ensures efficient plume dispersion with minimal back-pressure but risks deck contamination, whereas wet exhaust provides thermal suppression and signature reduction at the expense of higher engine load. Future work should explore transient, three-dimensional simulations for improved design guidance.

Keywords

CFD , marine exhaust systems , multiphase flow , thermal dispersion , turbulence

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