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.
Computational Fluid Dynamics Simulation of Structured Packing
An electronic representation of Sulzer’s Mellapak N250Y structured packing was generated by subjecting a physical packing element to CT scan. The resulting file was imported into a three-dimensional imaging program and then copied, translated, and rotated to create a stack of three packing elements. This stack was then inserted into an open-ended cylindrical surface to approximate a packed column. The resulting three-dimensional image file was imported into the Star-CCM+ CFD software and meshed using the Surface Remesher and Polygonal Volume Meshing routines to create a high-quality volume mesh. The mesh was then utilized to produce a series of CFD simulations. Flow rates were chosen so that the velocities studied would match those commonly employed in the vapor phase of industrial distillation columns. The pressure drop across the packing was monitored during iterative computations, and its rate of change was used to judge convergence. The simulation predictions were shown to be in good agreement with ex...
A comparative performance assessment of a hydrodynamic journal bearing lubricated with oil and magnetorheological fluid
Abstract This work presents the investigation results of a journal bearing lubricated with magnetorheological fluid that is activated by a local constant magnetic field to vary both the local flow resistance and pressure. The bearing performance is assessed via Finite Element Modelling (FEM) and results are corroborated by experiments. The FEM model uses the Bingham model to describe the fluid film. A dedicated test rig is used to assess the hydrodynamic behavior of the bearing with magnetorheological fluid, and the results are compared with the same geometrical bearing lubricated with oil. Thicker fluid films at low speeds, beneficial pressure distribution, and higher friction losses under all operating conditions are observed in the bearing with magnetorheological fluid compared to the oil lubrication.