| Description |
Multi-point ground flares are frequently used in scenarios where flare gas flow rates can be high and pollution (noise, light, smoke) needs to be minimized. We have applied Arches, a large eddy simulation (LES) tool that we have developed for capturing the dynamics of flares (turbulent mixing, local combustion efficiency (CE), etc.) and the impact of those dynamics on the quantities of interest (overall CE, heat flux to the surroundings, etc.), to multi-point ground flares. We use a handoff strategy to resolve the flow field in the near-burner region, coarsen the solution at a handoff plane, and then introduce the handoff plane outputs as source terms at the location of the flare tips in a multi-point ground flare mesh. Using this methodology, we perform large eddy simulations of the John Zink steamassisted SKEC multi-point ground flare test series (SN1) described in Marathon Petroleum Company's Flare Consent Decree1. Our handoff approach incorporates one-way coupling only; there is no feedback from the flow field back to the source terms injected at the flare tip. It is a compromise solution that allows us to compute the far-field flow dynamics of flares located adjacent to each other while incorporating the flow field generated by the fine-scale resolution of the flare tip. We will show the impact of the degree of coarsening (fine scale to multi-point flare scale), the location of the handoff plane, the location of the flare tips relative to each other, and the wind speed/direction on the computed overall CE. With this tool, we will be able to investigate effects such as cross-lighting and other interactions amongst multiple flares. |
