Integral models for bubble, droplet, and multiphase plume dynamics in stratification and crossflow

Abstract

We present the development and validation of a numerical modeling suite for bubble and droplet dynamics of multiphase plumes in the environment. This modeling suite includes real-fluid equations of state, Lagrangian particle tracking, and two different integral plume models: an Eulerian model for a double-plume integral model in quiescent stratification and a Lagrangian integral model for multiphase plumes in stratified crossflows. Here, we report a particle tracking algorithm for dispersed-phase particles within the Lagrangian integral plume model and a comprehensive validation of the Lagrangian plume model for single-and multiphase buoyant jets. The model utilizes literature values for all entrainment and spreading coefficients and has one remaining calibration parameter j, which reduces the buoyant force of dispersed phase particles as they approach the edge of a Lagrangian plume element, eventually separating from the plume as it bends over in a crossflow. We report the calibrated form j ¼ ½ðb À rÞ=b 4 , where b is the plume halfwidth, and r is the distance of a particle from the plume centerline. We apply the validated modeling suite to simulate two test cases of a subsea oil well blowout in a stratificationdominated crossflow. These tests confirm that errors from overlapping plume elements in the Lagrangian integral model during intrusion formation for a weak crossflow are negligible for predicting intrusion depth and the fate of oil droplets in the plume. The Lagrangian integral model has the added advantages of being able to account for entrainment from an arbitrary crossflow, predict the intrusion of small gas bubbles and oil droplets when appropriate, and track the pathways of individual bubbles and droplets after they separate from the main plume or intrusion layer.

Major CO2 blowouts from offshore wells are strongly attenuated in water deeper than 50 m

“…TAMOC is a multipurpose modeling suite for multiphase offshore oil and gas spill simulations, natural gas underwater releases, and single‐phase plumes. TAMOC includes capabilities to model major blowouts or ruptures and the transition to a buoyant bubble or droplet plume as entrainment and ebullition occur . For our purposes of modeling a CO 2 well blowout, we make use of TAMOC's built‐in equation of state model and the default TAMOC database including CO 2 chemical properties that extends TAMOC's applicability to CO 2 blowouts .…”

“…Integral approaches are simple, robust, and computationally efficient and have been used for decades in both single and multiphase contexts . TAMOC has been extensively tested and validated on both laboratory and field measurements of various kinds of fluid and gas releases . Inputs to TAMOC include the CO 2 leakage rate; the diameter of the orifice out of which the CO 2 is leaking; the water depth, temperature, and salinity of the seawater at the leak point; the temperature and salinity profiles in the water column; and the background large‐scale cross current in the water column.…”

“…[25][26][27][28][29][30] The tools developed for simulating high-flow-rate natural gas and oil releases are generally applicable to CO 2 releases provided an option exists to use an equation of state for CO 2 as an alternative to natural gas and oil. One such model with this capability is the Texas A&M oil spill (outfall) calculator (TAMOC), [31][32][33][34] which we use in this study.…”

“…TAMOC includes capabilities to model major blowouts or ruptures and the transition to a buoyant bubble or droplet plume as entrainment and ebullition occur. 31,34 For our purposes of modeling a CO 2 well blowout, we make use of TAMOC's built-in equation of state model 32 and the default TAMOC database including CO 2 chemical properties that extends TAMOC's applicability to CO 2 blowouts. 43 We further chose to use the bent-plume model (BPM) that handles the case of a buoyant CO 2 plume moving in ambient seawater with a nominal overall cross current.…”

Numerical Modeling of the Interactions of Oil, Marine Snow, and Riverine Sediments in the Ocean

“…For the five stations, the MacDonald et al () estimated surfacing oil fluxes vary between about 6 and 14 g week −1 m −2 . Predictions from deepwater oil and gas blowout plume models (Dissanayake et al, ; Johansen, ; Spaulding et al, ; Yapa & Li, ) can be used to calculate the oil in the water column, in intrusions, and on the surface. Spaulding et al () estimated that total insoluble hydrocarbon into the deep plume was 1.09 × 10 6 ± 1.422 × 10 5 during the DWH spill and Gros et al () estimates that about 73% petroleum mass remained in the water without dissolving in the days after the fallen riser was removed from the wellhead.…”