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Water Spray Interaction with Dense Gas Clouds

Submission by: Robert N. Meroney, PhD. Wind Engineering Software, and Civil and Environmental Engineering, Colorado State University, Fort Collins, CO., USA

Water spray curtains can provide an effective and rapid dilution mechanism for low-lying dense clouds. Frequently such clouds are released as a result of a chemical manufacturing, storage or gas transportation accident.

HSE 46 Schematic
HSE 46 Schematic

Extensive field and laboratory tests have been performed to determine how well water curtains can mitigate actual spill conditions. Numerical methods are often proposed to provide system design or timely response information, but most of these models reduce mathematical and computational complexity by integrating the equations of motion over volumes, sections or depths which provides computational speed but often sacrifices mixing detail and typically presume the use of empirical entrainment relationships.

Illustration of Simulated Phenomena
Illustration of Simulated Phenomena

In this study NIST FDS and Pyrosim have been used to reproduce the water-spray/cold carbon dioxide releases performed during a field experiment by the UK Health and Safety Executive (1981). Parallel wind tunnel experiments and box and slab models CFD models are also available. Thus, there is an opportunity to provide side-by-side comparisons of field, wind tunnel, box, slab and FDS CFD modeling methods.

A paper, "CFD modeling of water spray interaction with dense gas plumes" presented at the 13th International Conference of Wind Engineering, Amsterdam, July 2011 contains study details.

Without Spray Curtain

With Spray Curtain

Supplemental Images

20 Nozzles Total
20 Nozzles Total
Log Scatter Plot
Log Scatter Plot
Conical vs Radial Distance from Source
Concentration vs Radial Distance from Source
Conical vs Probe from A to O, Version 2
Conical vs Probe from A to O, Version 2
Percent Dilution
Percent Dilution
Forced Diffusion
Forced Diffusion
HSE 46, Cold CO2 No Spray C Contours at T=300s
HSE 46, Cold CO2 No Spray C Contours at T=300s
HSE 46, Cold CO2 No Spray C Contours at T=300s and Y=25m
HSE 46, Cold CO2 No Spray C Contours at T=300s and Y=25m
HSE 46, Cold CO2 Spray C Contours at T=300s
HSE 46, Cold CO2 Spray C Contours at T=300s