Bubble Separation Research Articles

The Self-Disproportionation of Enantiomers (SDE) of α-Pinene via Evaporation off Silica Gel and Foam Fractionation—Validation of the Plausibility of SDE via Gas Chromatography (GC) for α-Pinene

α-Pinene is an intriguing monoterpene as it has been reported to undergo the self-disproportionation of enantiomers (SDE) phenomenon via gas chromatography (GC), the only compound to decisively demonstrate this. Examples of the SDE involving the gaseous phase—sublimation aside—are extremely rare. Attempts to replicate the GC results were unsuccessful, though the authors argued convincingly for the difficulty of observing the phenomenon. However, we could effect for α-pinene SDE via evaporation off silica gel and by foam fractionation—albeit the SDE magnitude for both was only very slight—to confirm that α-pinene can undergo the SDE for processes involving a gaseous phase and thus validate the plausibility of the GC report. The indications are that the molecular associations responsible for the various SDE observations of α-pinene occur not in the gaseous phase or the bulk phase but rather in two-dimensional (2D) adsorbed monolayers and are not based on conventional functional group-based intermolecular interactions and instead are, most likely, as a result of homo- and heterochiral packing differences in the 2D monolayers—a well-known 2D chiral-based association packing effect. These are also the first reports of the occurrence of the SDE using an adsorptive bubble separation process (foam fractionation) and involving a gaseous phase other than sublimation, GC, and distillation.

Improvement of the bubble separation through eccentric planar cyclones: Experiments and CFD simulations

Planar cyclones have great advantages as electrolyzers, photocatalytic reactors, and gas–liquid separators. For planar cyclones, the separation efficiency of bubbles is a key parameter. The effect of eccentricity on bubble separation efficiency in planar cyclones was studied through a combination of experiments and simulations. When eccentricity dc = 0 mm, the separation efficiency of the bubbles decreased with an increase in the liquid injection velocity. This indicates that a greater centrifugal acceleration in planar cyclones does not contribute to bubble separation. Eccentricity dc = −5 mm resulted in a higher bubble separation efficiency. Each planar cyclone was divided into 12 sub-regions with equal areas. When eccentricity dc = −5 mm, subregions 11 and 12 exhibited larger bubble sizes, and a higher bubble separation efficiency was achieved. The area weighted average sauter mean diameter ds reached 0.47 mm and 0.475 mm and area weighted average gas volume fraction εs reached 2.75 % in subregion 11 when liquid Reynolds numberRel = 20075.4 and gas Reynolds number Reg = 23.8. The maximum separation efficiency can be increased from 43 % to 60 % when Rel = 20075.4 and Reg = 6.8 when the eccentricity varies from 0 to − 5 mm. Bubble size changes due to coalescence and breakup have an important influence on bubble separation. The trajectory of bubbles exhibits helix. The gradually decreasing curvature radius of the bubble trajectory dominates the bubble separation. Eccentric swirling field provides a sudden decrease in the swirl radius which promotes the reduction of the curvature radius of the bubble trajectory. This study provides an optimization method for the structural design of cyclones.

Coherent Structures and Pressure Fluctuations over an Airfoil Using Time-Resolved Measurements

This study focused on the unsteady behaviors of large-scale vortical structures and wall pressure fluctuations and their coupling mechanism on a low-Reynolds-number airfoil. Three incidence angles were chosen for comparison: , and (representing two flow regimes, namely, the separation bubble formation and separation without subsequent reattachment). Simultaneous measurements of velocity fields and wall-pressure fluctuations were performed using a high-resolution time-resolved particle image velocimetry operating at 2 kHz and an array of flush-mounted microphones sampled at 10 kHz. The results provided a detailed description of the shear layer transition and the coherent structures development on the airfoil. The roll-up process, pairing process, spatial-temporal growth of the vortical structure, and vortex break-up were clarified through a long-period analysis. Spectral analysis demonstrated that vortical structures at the fundamental frequency were spatially and temporally localized and that their subharmonics were significantly enhanced. Frequency–wavenumber spectra revealed that the energy was dominantly concentrated along the convective ridge. With increasing incidence angle, the energy level of the inclined ridge increased, with a lower extension in the frequency domain and a higher dispersion in the wavenumber domain. The conditional averaging and quadrant analysis results demonstrated that strong events in the near-wall region were dominated by the sweep motion and ejection motion, which enhanced the interaction between the inner and outer layers. This also indicated the existence of a strong relationship between the wall-pressure peaks and turbulence production mechanisms.

Sparging-based fission gas separation technology for molten salt reactor

Thorium molten salt reactor is one of the GEN-IV Molten Salt Reactors currently developed in China. The online removal of fission gases like Xenon and Krypton is a crucial technique to achieve high burnup of the liquid nuclear fuel. One of the promising candidates for practical application is the bubble sparging method, where tiny bubbles are first introduced into the liquid fuel, then the fission gases migrate to the carrier bubbles by interfacial mass transfer, and finally, a gas–liquid separator is used to remove the carrier bubbles along with the absorbed fission gases from the liquid. A thorough understanding of the mechanism and accurate modeling for the three sub-processes mentioned-above, namely bubble generation, mass transfer, and gas–liquid separation, are necessary for quantitative control of the fission gas removal performance.As for the bubble injection, the microbubble generating approach based on turbulent fragmentation mechanism is proposed, the predicting model of bubble diameter and the design criterion of bubble generator were established, constructing a generation and control technology of microbubbles for molten salt medium. For the mass transfer process, a novel numerical method simulating the interfacial migration of dissolved gases in bubbly flow is developed. Besides, a compact gas–liquid reactor with enhanced mass transfer efficiency applied to nuclear installations is proposed. In terms of the separation of bubbles, the separation length and stability of the swirling flow gas–liquid separator are investigated, and a solution of gas–liquid separation with ultra-high separation efficiency under extremely low gas fraction conditions is proposed. The feasibility and efficiency of the fission gas separation technology integrating all three procedures have been evaluated experimentally, providing a solid foundation for the future online post-processing of both off-gas and liquid fuel.

Effect and Mechanism of Cu Foams with Different Porosity on Kinetic Parameters of Ga Electrodeposition: Accompanied by Hydrogen Evolution Reaction

The process of Ga electrodeposition is usually accompanied by intense hydrogen evolution reaction, so the escape rate of hydrogen bubbles from the electrode surface has a great influence on Ga electrodeposition. In this paper, Cu foams with different porosity are applied to research the effect of escape rate of hydrogen bubbles on Ga electrodeposition. When Ga electrodeposition is controlled by mass transport process, Cu foams with high porosity exhibit a higher reaction rate of Ga electrodeposition because of its faster bubble escape rate. The larger pore channel diameter of Cu foam with low porosity reduces the escape rate of hydrogen bubbles and hinders the mass transfer process. The addition of surfactant accelerates the escape rate of bubbles from the electrode surface, thus promoting the mass transfer process and leading to the increase of the current efficiency of Ga electrodeposition. It is also found that the process of Ga electrodeposition is controlled by nucleation rate at the early stage. Due to the rapid separation of hydrogen bubbles, Cu foams with high porosity provide more effective sites per unit surface area. Therefore, Cu foams with high porosity have a higher nucleation rate and a lower induced time for Ga electrodeposition.

Single bubble probe atomic force microscope and impinging-jet technique unravel the interfacial interactions controlled by long chain fatty acid in anaerobic digestion

Anaerobic digestion of lipid-rich wastewater generally suffers from foaming induced by long chain fatty acid (LCFA). However, a systematic understanding of LCFA inhibition, especially the physical inhibition on interfacial interaction still remains unclear. Here, we combined bubble probe atomic force microscope and impinging-jet technique to unravel the interfacial interactions controlled by long chain fatty acids in anaerobic digestion. We showed that LCFA had a significant inhibition on methane production in anaerobic reactors for the inhibition of the conversion of VFAs to methane. By measuring the LCFA influence on methanogenic archaea Methanosarcina acetivorans C2A, the results demonstrated that methanogenesis was limited for substrates utilization but not metabolic pathways. The impinging-jet technique results indicated that LCFA enhanced bubble separation from anaerobic granules and reduced the bubble-bubble coalescence probability. In addition, the bubble probe atomic force microscope (AFM) revealed that LCFA enhanced the adhesion force between bubbles by enhancing electrical double layer (EDL) repulsion and decreasing hydrophobic interactions. Overall, these results complement framework of LCFA inhibition in anerobic digestion and provide a nanomechanical insight into the fundamental interfacial interactions related to bubbles in anaerobic reactors.

Design of a high-efficiency electrolytic energy conversion system based on equilibrium analysis of electric-field and flow-field through simulation and experiments

In the context of sudden changes in global energy supply patterns, promoting the diversification of energy supply is an important movement for the sustainable development of the economy. Nuclear energy as a green and clean energy source has undergone rapid development. About 60 wt% of the world's fluorine production is used to produce uranium, a fuel for nuclear power plants. However, fluorine as a necessary raw material facing the challenges of high energy consumption and short lifespan of the electrolysis system. To overcome these drawbacks, this study aims to develop a high-efficiency electrolytic energy conversion system. Therefore, to optimize the design of the electrolysis system, the relationships between the electric field, the flow field and the electrode/electrolyzer geometry are simulated. Then, the simulation results are verified and further corrected by corrosion experiments. Subsequently, the key factors affecting the performance of the electrolyzer are obtained from the bubble separation experiment and simulation. Finally, a high-efficient electrolysis system is established and successfully put into industrial operation. In conclusion, in the course of model calculations, the method of reducing energy consumption is put forward, and the energy consumption is reduced from 17,000 to 14,980 kWh/ton by actual production, and the service life of carbon anode is extended from 90 days to 243 days. The breakthrough in fluorine electrolysis provides practical guidance for improving the performance of the electrolysis process.

Comparisons of Structured Surface Floors for Pool Boiling Enhancement at Low Heat Fluxes: Hands-On Learning Setup for Heat Transfer Classroom

Various enhanced surfaces have been proposed over the years to improve boiling heat transfer. This paper introduces an experimental setup designed for boiling demonstration in the graduate-level Heat Transfer course. The pool boiling performance of water under atmospheric pressure of 1.025 bar is investigated by using several structured surfaces at heat fluxes of 28 and 35 kW/m2. Surfaces with holes, rectangular grooves, and mushroom fins are manufactured by an NC-controlled vertical milling machine. The heat flux versus excess temperature graph is plotted by using thermocouple measurements of water and base temperatures of the boiling vessel. The separation, rise, and growth of individual vapor bubbles from the surface during boiling were recorded with a digital camera. The results for the plain surface are compared to the Rohsenow correlation. The enhancement of heat transfer coefficient (h) ranged between 15% - 44.5% for all structured surfaces. The highest heat transfer coefficient enhancement is observed between 41% - 56.5% for holed surface-3 (405 holes) compared to the plain surface. The excess temperature dropped around 29% - 34% for holed surface-3 (405 holes) compared to the plain surface. The heat transfer coefficient increases as the spacing between channels or holes decreases. While the bubbles on holed and mushroomed surfaces were spherical, the bubbles on the flat and grooved surfaces were observed as formless. The suggested economical test design could be appropriate to keep students focused and participating in the classroom.

Advanced Treatment of Pharmaceutical Wastewater with Bubble Separation Coupled with Advanced Oxidation Process

Advanced Treatment of Pharmaceutical Wastewater with Bubble Separation Coupled with Advanced Oxidation Process

Effect of Leading-Edge Gap Size on Multiple-Element Wing NACA 43018

Generally, large airplanes are added with more than one high lift device to improve aerodynamic performance. Each configuration of the addition of high lift devices will result in different aerodynamic performances. The added high-lift devices include flaps, leading-edge slats, vortex generators, fences, and others. This study shows the aerodynamic performances of the NACA 43018 wing airfoil with the addition of leading-edge slats and plain flaps in cruise conditions with variations of leading-edge gap size. The angles of attack used include 0°, 2°, 4°, 6°, 8°, 10°, 12°, 15°, 16°, 17°, 19°, and 20°. Numerical simulations have been performed using Ansys Fluent 19.1 with a k-ε Realizable turbulent model. The aerodynamic performance of the configuration that uses the leading-edge slat shows a higher value than the rectangular wing even though the lift and drag coefficients produce lower values. The use of leading-edge slats produces fluctuations, which are indicated by different values of the pressure coefficient, that show the interaction of adding momentum from the main flow from the direction of the leading edge. The increase in the angle of attack causes bubble separation in the leading-edge gap size, which is like a pseudo-body transforming from convergent to smaller.

Adsorptive bubble separation method in the recovery of a biomolecule

AbstractThe present work aims to separate an amino acid (l‐phenylalanine) from a highly dilute aqueous solution by the ‘adsorptive bubble separation method’. Separation is based on the principle of adsorption at the interphase of the gas bubble and aqueous phase and subsequent amino acid extraction in the top layered nonaqueous phase. The operation was carried out in a long glass column with a comprehensive solvent chamber at the top. Design‐Expert software optimizes the process parameters, and the process involves three variables: gas (nitrogen) flow rate, extractant, and solvent quantity, which control responses, recovery percentage, and the ratio of enrichment. The design models are found to be significant. The maximum recovery of amino acid observed was 75.545% and the value of the enrichment ratio was 3.87. In addition, two models were generated by the software, which was statistically significant (P < 0.05). Therefore, this process is adopted as it is of straightforward construction, eco‐friendly, and less costly than other methods previously known to recover l‐phenylalanine from a dilute solution. © 2022 Society of Chemical Industry (SCI).

Kinetic model of PFAS removal by semi-batch foam fractionation and validation by experimental data for K-PFOS

Adsorptive bubble separation techniques such as foam fractionation have recently been applied for the extraction of per- and polyfluoroalkyl substances (PFAS) from waters at both laboratory and operational scales. However, few authors have developed mathematical models of their removal of PFAS. This study presents a theoretical framework for the kinetics of PFAS removal from fresh and monovalent saline waters by a semi-batch foam fractionation process, by the mechanisms of adsorption, entrainment and volatilization, as a function of pertinent parameters including PFAS air-water adsorption, bubble radius, electrolyte concentration and ionic strength, PFAS volatility, and flow and geometric parameters. The freshwater model is validated for the removal of potassium perfluorooctane sulfonate (K-PFOS) using published experimental data (Meng, P. et al., Chemosphere, 2018, 203, 263–270). The proposed models provide quantitative tools for process design and the optimization of individual PFAS removal by semi-batch adsorptive bubble separation techniques such as foam fractionation.

Experimental and numerical study on the length of LZVV in the bubble separator for molten salt reactor

The bubble separator using centrifugal technology is the key device to remove the fission gas from the molten salt in the molten salt reactor. The Locus of Zero Vertical Velocity (LZVV) is an important characteristic of swirling flow. In this paper, a new measuring method is introduced to obtain the length of the LZVV of the bubble separator by tracking the droplet trajectories and analyzing the particular droplets’ location at the single-phase condition. The effects of the flowrate, split ratio and the flowrate distribution of the two Light Phase Outlets (defined as LPO ratio) on the length of LZVV are studied. Moreover, numerical simulation at single-phase condition is carried out using the Reynolds stress model and it shows a good agreement with the experimental result. The experimental and numerical results show that the velocity distribution does not change with the flowrate and the larger split ratio leads to a longer length of LZVV and stronger swirl strength.

Experimental Study of Bubble Dispersion Characteristics in a Nonuniform Electric Field

The application of electric fields can intensify the dispersion characteristics of discrete phase in continuous phase. In charged liquid–gas dispersion systems, there are important processes, such as bubble formation, motion, and interaction, which are quite different from hydrodynamic processes without external fields. In the present study, the bubble dispersion characteristics were experimentally studied in ethanol under a direct current (DC) nonuniform electric field. By considering the voltage and flow rate, the dispersion pattern, trajectory, size distribution, velocity, and deformation of the bubbles were examined using high-speed photography. A considerable control over the bubble dispersion patterns, including isolated, chain, and diffusion patterns, can be achieved by careful consideration of the experimental parameters. The bubbles dispersion in liquid under the electric field can detach with a considerably smaller diameter than that without electric field. Both the increase in electrical Bond number (BoE) and gas Reynolds number (Reg) intensifies the interaction between bubbles. The BoE works to accelerate the separation of smaller bubbles, while the Reg works to reinforce the wake induction. In addition, the cross-sectional bubble size distributions, velocities, and bubble shapes corresponded to the bubble dispersion patterns.

Binder-free electrochemical deposition of 3-D superhydrophilic Cu-Fe-P nanostructure for improving urea oxidation and hydrogen evolution reaction

• Cu-Fe-P electrodes were fabricated at various applied current densities. • Electrodeposited electrodes showed favorable catalytic activity for HER and UOR. • Application of UOR instead of OER reduced the overpotential for hydrogen production. Electrochemical water splitting, which includes the hydrogen and oxygen evolution reactions at the cathode and anode surface is one of the eco-friendly and sustainable approaches for hydrogen production. However, due to the needing for high overpotentials in the oxygen evolution reaction (OER) process, electrochemical water splitting still is not economical process. Therefore, replacing the OER with the urea oxidation reaction (UOR) can provide more effective hydrogen production opportunities. Therefore, in this study, by using the electrodeposition process at high current densities and substantial evolution of hydrogen bubbles during the process, the three-dimensional and nanostructured Cu-Fe-P electrode was synthesized. Due to the high active surface area, electrolyte diffusion into all the pores, rapid separation of bubbles, and being binder-free, the deposited Cu-Fe-P electrode at an applied current density of 2 A.cm -2 has the best electrocatalytic performance. It was represented that the value of the needed overpotential for achieving the current density of 10 mA.cm -2 (η 10 ) for the hydrogen evolution reaction (HER) was only 56 mV, and the potential value for obtaining the same current density in the UOR was only 1.295 V (vs. RHE). Similarly, when this electrode was used as a bi-functional electrode in the water-urea electrolysis process, the value of cell voltage was 1.365 V. Also, the prepared catalyst indicated excellent electrocatalytic stability. This work suggests a simple and ultra-fast method for economic electrochemical hydrogen production.

Determining the influence of wastewater hydrodynamics in bioreactors on the process of mass transfer

The anaerobic method of treating wastewater from biotechnological and economic industries has great prospects for the development of a renewable energy source. Biogas released during the operation of the bioreactor can be used as an energy source for the generation of electricity and heat. This paper reports the design of an apparatus for wastewater treatment with microorganisms immobilized on inert carriers. The original substrate supplied to the bioreactor is heated by thermostating. The temperature of the original substrate is controlled using an electronic temperature meter. Temperature in the bioreactor is also controlled; maintaining the methane growth of microorganisms in the range of 35–37 °C is enabled by a temperature sensor. The gas that is released during the experiment is collected in a gas collector, where its volume is measured, owing to the torn cylinder connected to the gas collector. Additionally, a temperature sensor is installed in the gas collector to determine the mass of the biogas collected in the experiments. Owing to the high-speed camera connected to a computer, the process of formation and separation of gas bubbles from the biofilm is recorded, as well as the thickness of the biofilm on flat carriers. To determine the effect of hydrodynamics under a laminar mode of wastewater supply, in the bioreactor channels, a peristatic dosing pump is used in the experimental installation. In the experiments, the thickness of the biofilm changed in the range from 10-3 m to 4.8·10-3 m and, because of this, the width of the channel along which the substrate flow moved changed accordingly. Experimentally, it was established that the volume of biogas released increases with an increase in the rate of wastewater in the bioreactor channels. Based on the experimental results, a criterion equation was built using which can determine the coefficient of mass yield

New Nanofiber Composition for Multiscale Bubble Capture and Separation.

Bubble dynamics inside a liquid medium and its interactions with hydrophobic and hydrophilic surfaces are crucial for many industrial processes. Electrospinning of polymers has emerged as a promising fabrication technique capable of producing a wide variety of hydrophobic and hydrophilic polymer nanofibers and membranes at a low cost. Thus, knowledge about the bubble interactions on electrospun hydrophobic and hydrophilic nanofibers can be utilized for capturing; separating; and transporting macro-, micro-, and nanobubbles. In this study, poly(methyl methacrylate) (PMMA) and PMMA-poly(ethylene glycol) (PEG) electrospun nanofibers were fabricated to investigate gas bubble interactions with submerged nanofiber mats. To improve their durability, the nanofibers were reinforced with a plastic mesh. The ultimate tensile strengths of PMMA and PMMA-30%PEG nanofibers were measured as 0.35 and 0.30 MPa, respectively. With the use of reinforcement mesh, the mechanical properties of final membranes could be improved by a factor of 70. The gas permeability of the electrospun and reinforced nanofibers was also studied using the high-speed visualization technique and a homemade setup to investigate the effect of electrospun nanofibers on the bubble coalescence and size in addition to the frequency of released bubbles from the nanofiber mat. The diffusion rate of air bubbles in hydrophobic PMMA electrospun nanofibers was measured as 10 L/s for each square meter of the nanofiber. However, the PMMA-30%PEG mat was able to restrict the diffusion of gas bubbles through its pores owing to the van der Waals force between the water molecules and nanofiber surface as well as the high stability of the thin water layer. It has been shown that the hydrophobic electrospun nanofibers can capture and coalesce the rising gas bubbles and release them with predictable size and frequency. Consequently, the diameter of bubbles introduced to the hydrophobic PMMA membrane ranged between 2 and 25 mm, whereas the diameter of bubbles released from the hydrophobic electrospun nanofibers was measured as 8 ± 1 mm. The proposed mechanism and fabricated electrospun nanofibers can enhance the efficiency of various systems such as heat exchangers, liquid-gas separation filters, and direct air capture (DAC) systems.

The Investigation of the Bubble Behaviors on the Vertical Heat Exchange Tube

In the boiling process, the growth, separation, and movement of bubbles are expeditious. The visualization experiment of nucleate boiling was carried out with the help of high-speed photography. The evolution of the entire bubble life cycle is clearly observed at the nucleation site without interference from the leading and neighboring bubbles. Bubble behavior at the local heating surface has strong randomness due to the influence of the wall micro-structure, convection intensity, heating surface geometry configuration, heat flux density, and so on, but bubble behavior also has a certain regularity. In this paper, the behavior characteristics of bubbles were analyzed, with a particular focus on the evolution of bubbles. Under lower load (ΔTsat = 8~9 °C) in study conditions, nucleation sites have a long enough time interval. In addition, the bubble separation and rising velocity obviously increase due to the change of pool boiling flow characteristics in the restricted space. The setting of confined space increases the bubble escape velocity and the rising velocity, and decreases the diameter of bubbles escaping from the wall. The results will provide some help for the understanding of bubble behavior mechanisms and numerical research.

Study of micro-heater shape and wettability effects on inception of boiling phenomenon using a multiphase lattice Boltzmann method

In the present paper, the inception of boiling phenomenon and the resulting bubble dynamics are investigated using a multiphase lattice Boltzmann method (LBM). Two equations of state (EoS), namely the Peng-Robinson (P-R) and the Redlich-Kwong-Soave (R-K-S), are employed and their capability for the prediction of the bubble nucleation, growth, and departure is evaluated against the available data in the literature. The effect of the micro-heater surface wettability and shape, namely the grooved and cavity, are studied on the separation time and velocity of the detached bubble at different flow conditions. Based on the present results, the boiling phenomenon nucleates from sharp-angled edges of the groove and cavity that are the region with higher temperature gradients. For the hydrophilic heated surface, the growth of the bubble continues on the sharp edges with the minimum dry spot on the surface. However, the hydrophobic heated surface tends to attract the forming bubble in the inception process, so that the boiling bubble is flattened on the heated surface after formation and tends to stick to the micro-heater. It is found that the bubble separation time from the micro-heater surface is longer, and the departure velocity is lower for the hydrophobic heated surface in comparison with the hydrophilic wetting condition. Also, the present study shows that the bubble separation from the grooved micro-heater occurs faster and with a higher velocity in comparison with the cavity micro-heater at a certain contact angle that demonstrates the significant effect of the surface shape on the boiling phenomenon. Hence, the grooved micro-heater is incorporated with two triangular pillars. The results demonstrate that using pillars provides more time for the bubble to grow before departure from the surface due to the blockage of the liquid flow coming from the lateral sides to the bubble formation site.

Simulation of the Axial-Flow Centrifugal Bubble Separator for Liquid-Fueled Molten Salt Reactors Using Eulerian Two-Fluid Model

The axial-flow centrifugal bubble separator designed for the gaseous fission product removal system in liquid-fueled molten salt reactors is simulated using the Eulerian two-fluid model coupled with the Adaptive Multiple Size Group method to account for the significant coalescence and breakup in the bubble separator. The behavior of the gas core in the bubble separator is mimicked by the symmetric interfacial area concentration model. The separator efficiency, local velocity, and pressure profiles at various conditions are compared with experimental data. Good agreement is found between the experiment and the simulation for the separator efficiency. With the coalescence and breakup being accounted for, the effect of the inlet void fraction on the separator efficiency is correctly captured. For the local pressure and velocity profiles, the agreement is only quantitative due to the simplifications on the geometry and potential limitations of the current computational fluid dynamics models. As good agreement is found for the separator efficiency, the sensitivity study is performed for various operational and design parameters with further simplified two-dimensional axisymmetric simulation.