Gas-liquid multiphase computational fluid dynamics (CFD) of amine absorption column with structured-packing for CO2 capture
Abstract The gas−liquid multiphase Eulerian computational fluid dynamics (CFD) model was used to investigate hydrodynamics and CO2 removal efficiency of a pilot-scale amine absorber with structured-packing. The structured-packing was represented by a porous media zone having porous resistance, gas−liquid interfacial drag force, and liquid dispersion force. This study aimed to find a reasonable way to identify four modification factors of the Ergun coefficient that determine the hydrodynamic characteristics of structured-packing. The two modification factors (a and b) for porous resistance were mainly related to the liquid holdup (hL) with respect to the liquid load. The other two factors (c and d) for gas−liquid interfacial drag force depended on the specific wet pressure drop (ΔPwet/L) versus the gas load factor. The hL and ΔPwet/L increased in parallel with the increase of a and c, respectively, while the slopes of hL and ΔPwet/L increased with b and d, respectively.
On the effect of the Froude number on the interface area of gravity-driven liquid rivulets
Abstract The morphology of gravity-driven rivulets affects the mass transfer performance in gas separation processes, hence, the need for an improved knowledge on the hydrodynamics of this flow. It is well established that the interface area of the rivulets is determined by the balance between inertia and surface tension, i.e. the Weber number, which in light of the results presented here, are not the only parameters involved, but also the inclination of the plate has an effect on the balance of forces which determines the amount of gas–liquid interface area. The analysis of the interface area in rivulet flow demands, therefore, a more complete physical explanation for packing design purposes. In this work, we analyse the combined effect of both the inertia and the inclination of the plate in the interface area of liquid rivulets using CFD and the volume-of-fluid interface tracking method. As a result, we propose the use of the Froude number to provide a more complete physical explanation on the interface area formation of gravity-driven liquid rivulets.
Role of the coronoid process in varus osteoarticular stability of the elbow.
The role of the coronoid process in varus osteoarticular stability of the elbow was investigated in 10 cadaveric elbows. Testing was performed at multiple flexion angles after incremental removal of the coronoid. At each flexion angle, removal of more than 50% of the coronoid produced a statistically significant decrease in the load resisting varus displacement compared with all lesser resection levels (P < .003). There was a trend for decreasing load after removal of 50% of the coronoid. The mean decrease in load across all flexion angles was 10.1%, 50.4%, and 75.4% after removal of 50%, 75%, and 100% of the coronoid, respectively. Resistance to varus displacement tended to decrease more as a percent of control at lower flexion angles than at higher flexion angles after removal of more than 50% of the coronoid. The coronoid process was found to be a key varus stabilizer in the elbow and may contribute more to elbow stability in extension than in flexion.