Abstract
A numerical investigation of the spray-induced turbulence generated from industrial spray nozzles is carried out to better understand the roles of the nozzle spray on the fires or explosions in different accidental scenarios. Numerical simulations are first validated against experimental data in the single nozzle case using the monodisperse and polydisperse assumption for droplet diameters. The polydispersion of the nozzle spray is proven to be necessary to correctly predict the gas and droplet velocities. The turbulent kinetic energy has dominant values inside the spray cone, decreases rapidly with the vertical distance from the spray nozzle, and is strongly affected by the spray droplet diameter. On the contrary, the integral length scale is found to have high values outside the spray cone. Two interacting sprays injected from different nozzles are then investigated numerically using the validated polydisperse model. The water sprays generated from such industrial nozzles can generate turbulence of high intensity in the near-nozzle region, and this intensity decreases with the distance from the nozzles. A better understanding of the turbulence generated by the spray system can be beneficial for the evaluation of several important phenomena such as explosion enhancement. The guideline values obtained from this investigation of single and double nozzles can be useful for large-scale numerical simulations.
Highlights
Published: 20 February 2021Water spray systems are commonly used as emergency devices for fire mitigation purposes in gas processing plants [1], power plants, and offshore platforms [2]
The spray-induced turbulence generated from industrial nozzles is investigated numerically using an Reynolds-Averaged Navier–Stokes (RANS) turbulence model
In both the single- and two-nozzle cases, the spray-induced turbulence is noted to be more intense inside the spray cone
Summary
Water spray systems are commonly used as emergency devices for fire mitigation purposes in gas processing plants [1], power plants, and offshore platforms [2]. Many factors are involved in the physical modeling, such as the water flow rate, droplet size distribution, injection velocity, etc These factors are usually coupled and have different values depending on the nozzle types. The industrial fire mitigation water sprays have much larger geometries (O (1–10 m)) than the fuel sprays in combustion These two approaches can hardly be applied directly in engineering applications of large-scale geometries as a result. The smallest grid sizes for these problems can be around ∆x ≈ O (10 cm), and the direct application of these highly-resolved turbulence models, involving the action of spray and spray-flame interaction, can give erroneous results. We try to use the Reynolds-Averaged Navier–Stokes (RANS) models to evaluate the turbulence generated from one single and two interacting industrial spray nozzles in order to find guideline values for the turbulence intensity in large-scale simulations.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
