Gas Flow Research Articles

Smelting Reduction of HIsarna Slag with Methane

To study the smelting reduction behavior of methane in the HIsarna process, the isothermal reduction experiments of HIsarna slag with 6 wt% of FeO were conducted at the temperatures of 1450, 1475, and 1550 °C, using 5 vol% CH4‐Ar. The effect of the gas injection flow rate on the overall reduction rate was investigated in the range of 0.5–1.5 L min−1. The results confirm that the decomposed carbon black acts as the dominant reductant in the reduction process compared to hydrogen. Increased gas flow rate increases the reaction rate, while temperature shows no significant effect. The reduction process could be described by the JMAEK model: by fixing the gas flow rate at 1.0 L min−1 with different temperatures, the exponent n value is around 1.5, indicating FeO mass transfer is the limiting step since there are sufficient carbon blacks as nucleation sites. The reduction process follows the first‐order model controlled by the reactant concentration with the gas flow rate being at 0.5 L min−1 and in the second reaction stage of the gas flow rate at 1.5 L min−1. The determined activation energy for the methane reduction is 59.8 kJ mol−1.

Off-design analysis of the inverted Brayton cycle engine

Purpose The purpose of this study is to perform an off-design analysis of the inverted Brayton cycle engine. Design/methodology/approach The off-design analysis equations of the inverted Brayton cycle engine were first derived in this study and the control parameters of the inverted Brayton cycle engine were first determined and investigated. Findings It is observed that by controlling the total temperature decrease in cooling section, it is possible to adapt the engine for low specific fuel consumption working conditions or high thrust working conditions. Specific fuel consumption is reduced by 27.1 % by stopping cooling in the cooling section and thrust is increased by 27.6 % by working with full load of the cooling section (500 K temperature decrease in cooling section). It is observed that thrust depending on the flight Mach number increases with an increase in flight Mach number and reaches a peak value at 5.21 flight Mach number and reduces by 80.8 % at 6 flight Mach number relative to the peak value. The specific fuel consumption increases rapidly as the Mach number increases, and the specific fuel consumption is 49.0 g/[kN.s] at Mach 1, reaches 70.4 g/[kN.s] at Mach 5 and increases to 412 g/[kN.s] at Mach 6. The specific fuel consumption increases from 68.1 to 73.0 g/(kN.s) and the thrust decreases from 16.5 to 13.3 kN as the total preburner exit temperature increases from 1,500 to 2,000 K. Specific fuel consumption decreases from 83.1 to 64.8 g/(kN.s) and thrust increases from 4.60 to 11.08 kN depending on afterburner exit total temperature increase from 1,800 to 2,500 K. Research limitations/implications The cooling section reduces total temperature of the gas flow to lower values to increase the compressor total pressure ratio. The compressor increases the total pressure of the gas flow to the optimum total pressure ratios to increase the nozzle exit Mach number and gain more thrust. The afterburner increases the total temperature of the gas flow to increase the sound speed in the nozzle exit to increase thrust. The nozzle expands the gas flow to reduce the static pressure of the gas flow to near the optimum value, atmosphere pressure, to increase thrust and reduce specific fuel consumption. Practical implications Hypersonic and supersonic air vehicles can use the current engine model for the its own propulsion systems. Social implications After first heavier than air flight, aero engines was designed for only used for aero vehicle. Internal combustion engines were used for propelled propeller aircraft at the first term of aircraft. However, propeller-propelled aircrafts are not sufficient to increase aircraft velocity to supersonic Mach numbers due to the shock losses of propeller, so the supersonic era was only introduced by revolution in propulsion systems with new concept. A jet engine was developed to be candidate for supersonic flight. Originality/value Off-design analysis equations of an inverted Brayton cycle engine were first derived in this study. Furthermore, the control parameters of the inverted Brayton cycle engine were first determined and investigated in this paper.

Experimental Investigation of Film Thickness in Wastewater Airlift Pumps by an Image Processing Method

The airlift pump is a key part of wastewater treatment and is employed as an innovative and feasible collection tool. However, as one of the key factors in the lifting capability of airlift pumps, film thickness in the gas–liquid two-phase flow operating in pumps is still an unknown topic because it is difficult to measure. This paper proposes a visualization method for measuring film thickness and investigates the film thickness when operating under gas flow with a high rate in airlift pumps using experiments. Firstly, a simulation experiment platform was built, and the images of the film structure were acquired by a high-speed camera. Then, image-processing technology and an image distortion correction were proposed to extract the gas–liquid interface for studying the thickness of the film. The experimental results demonstrated that a large film thickness ranging from 0.15 D to 0.24 D was found in airlift pumps and that its film thickness kept a constant value, even under a high gas superficial velocity, maintaining a large output liquid flow from airlift pumps. As wastewater was carried by wastewater treatment, a larger film thickness of the annular film will benefit the high lifting rate of wastewater. The works in this paper offer valuable insights for the higher performance of working airlift pumps and wastewater treatment efficiency.

Impact of H-Related Chemical Bonds on Physical Properties of SiNx:H Films Deposited via Plasma-Enhanced Chemical Vapor Deposition

SiNx:H film deposition via plasma-enhanced chemical vapor deposition has been widely used in semiconductor devices. However, the relationship between the chemical bonds and the physical and chemical properties has rarely been studied for films deposited using tools in terms of the actual volume production. In this study, we investigated the effects of the deposition conditions on the H-related chemical bonding, physical and chemical properties, yield, and quality of SiNx:H films used as passivation layers at the 28 nm technology node. The radiofrequency (RF) power, electrode plate spacing, temperature, chamber pressure, and SiH4:NH3 gas flow ratio were selected as the deposition parameters. The results show a clear relationship between the H-related chemical bonds and the examined film properties. The difference in the refractive index (RI) and breakdown field (EB) of the SiNx:H films is mainly attributed to the change in the Si–H:N–H ratio. As the Si–H:N–H ratio increased, the RI and EB showed linear growth and exponential downward trends, respectively. In addition, compared with the Si–H:N–H ratio, the total Si–H and N–H contents had a greater impact on the wet etching rates of the SiNx:H films, but the stress was not entirely dependent on the total Si–H and N–H contents. Notably, excessive electrode plate spacing can lead to a significant undesired increase in the non-uniformity and surface roughness of SiNx:H films. This study provides industry-level processing guidance for the development of advanced silicon nitride film deposition technology.

Investigation of current density and temperature distribution characteristics under transient conditions based on a 108 cm2 segmented proton exchange membrane fuel cell

Visualizing the electrochemical and temperature distribution characteristics inside proton exchange membrane fuel cell (PEMFC) should greatly contribute to the product development and performance optimization. In the study, a customized 27-segment 108 cm2 fuel cell was fabricated based on the printed circuit board methodology to achieve the local current density and local voltage measurement. In addition, 27 thermocouples were embedded in the segmented cathode graphite gas flow plate for local temperature measurement. Detailed information of fuel cell core components, multi-channel data acquisition system, external temperature control system, and uncertainty analysis was presented. According to the test results of 4000 s current rising conditions and 2400 s current decreasing conditions, the measurement deviation of total current between data acquisition system and TOYO test station is 2.4%–3.2%. Meanwhile, the deviation of output voltage ranges from 0.1% to 2.6%. To quantify the degree of distribution non-uniformity, the range and standard deviation of local parameter values as well as contour map are demonstrated. The non-uniformity of local current density and local temperature becomes more significant under higher operating current conditions. Furthermore, the degree of parameter non-uniformity is more noticeable under current rising conditions compared with current decreasing conditions. The transient increase of operating current leads to the sudden overshoot phenomena of local current range, and the change of local current density among all segments is instantaneously finished. However, the range of current demonstrates relatively smooth transition trends when reactant flow rate rises. Higher temperature area appears in the middle of membrane electrode assembly, especially in the position with higher local current density. The parameter distribution and transition characteristics could provide helpful guidance for fuel cell optimization and diagnosis.

Design and characterization of a nano‐pulsed atmospheric pressure plasma jet for biomedical applications

AbstractPlasma jets, crucial atmospheric pressure sources in biomedical applications, generate reactive species in liquids, with electrical fields playing a significant role, as variations in pulse rise times and durations in dielectric barrier discharges yield diverse effects. This study presents a novel nanosecond pulse plasma jet. Here, investigations with phosphate‐buffered saline and Ringer's saline elucidate critical parameters influencing species generation, such as treatment time and gas flow rate. Results showed increasing concentrations of H2O2 and NO2− over time, with NO2− degrading faster in Ringer's saline due to acidification. The nanosecond pulse jet exhibits superior energy efficiency than conventional jets, laying the groundwork for optimizing species generation and studying electrical field effects in future biological works.

Hydrogen reduction studies of low-grade multimetallic magnetite ore pellets

The hydrogen reducibility of pellets made from a low-grade multimetallic magnetite ore (Fe content ∼ 45 %) was investigated in the present study. Pellets were reduced in a horizontal tube furnace at temperatures ranging from 973 K to 1173 K for 1 to 60 min. Pure Hydrogen (H2) gas (99.9 %) at three flow rates of 0.25 L/min, 0.5 L/min, and 1 L/min were blown during the reduction process. A maximum reduction degree of 94.07 %, metallization ratio of 0.925, and H2 gas utilization of 9.01 % were obtained at a temperature and a reduction time of 1173 K and 60 min, respectively. In order to optimize the hydrogen utilization, a reduction temperature of 1173 K, a reduction time of 45 min, and a gas flow rate of 0.25 L/min were selected, resulting in a reduction degree and metallization ratio of 90 % and 0.89, respectively. The cold crushing strength (CCS) of the reduced pellets initially decreased and then increased slightly, exhibiting behavior similar to high-grade ores. Imputities like SiO2, Al2O3, and MgO, present in the low grade ores are found to control the porosity of the pellets, directly affecting the CCS and reducibility of the pellets.

A device for dynamic testing of the refractory ceramic resistance to biomass ash

The corrosive effects of biomass ash on refractory materials in combustion chambers pose challenges. Development of new castable refractory materials which are more resistant to corrosion requires tests that accurately reflect the conditions occurring in real devices. This article describes the Computational Fluid Dynamics (CFD) design and construction of a device for evaluating the corrosion of refractory materials in dynamic regime. The device allows to simulate combustion chamber conditions accurately, to regulate an injection of corrosive medium on the tested material surface under the specified conditions (temperature, time, and flow). In the present investigation the conventional refractory material was exposed to attack of biomass ash at the temperature of 1300 °C for 3 h to test the functionality of the device. A burner with technology oxygen–enriched combustion was used to heat the device. The corrosion tests were conducted in accordance with the standard P CEN/TS 15,418 and the standard STN EN ISO 21404. The operational state required for corrosion tests at 1300 °C was achieved within 1.12 h. The extent of refractory material degradation in the dynamic corrosion regime was evaluated using electron microscopy-energy dispersive spectroscopy (EM-EDS) and compared with the results of a static crucible test (3 h at 1300 °C). The dynamic test provided sufficient information on the interactions of corrosion medium with the refractories. Its main advantages are the maintenance of non-equilibrium conditions by controlled deposition of the corrosion medium in quantity from 1 to −100 g/h, fast heating rate to operating temperature (20 °C/min), and the possibility of conditions variability during tests (temperature, ox-red. atmosphere, fuel gas flow etc.).

Assessing Coriolis meter performance in multicomponent carbon dioxide-rich mixtures

Accurate flow measurement plays a pivotal role in monitoring CO2 flows across the CCS value chain. This not only bolsters the overall business model of the CCS industry, but also ensures adherence to environmental legislations and regulatory requirements. Unlike other industrial process fluids, such as water, oil & natural gas, it is unclear whether current commercially available metering technologies can meet the requisite accuracy levels, specifically the ±2.5 % recommended within the EU/UK European Trading Scheme for CO2 mass transfer. Accordingly, the aim of this work was to gain a comprehensive understanding of CO2 flow measurement within the context of CCS transport conditions. Firstly, GERG-2008 equation of state was implemented on REFPROP v10 to predict the optimal transport conditions for CO2-rich mixtures and to understand the influence of non-condensable gas impurities in CCS flow operations. Then, a dedicated laboratory-scale gravimetric flow facility was designed and used to evaluate the performance of a Coriolis flow meter under gas, liquid, and supercritical flow conditions. The results indicate that the impurities have a relatively minor impact on the measurement performance of the meter, with maximum mean absolute measurement errors of 0.25 %, 0.12 %, and 0.28 % observed in gas, liquid, and supercritical CO2 flow conditions, respectively. The findings support the use of Coriolis metering technology as a reliable option for CCS metering, underscoring its suitability for accurate measurements in single-phase CO2 transport applications.

Justification of the Locations of Differential Pressure Sensors for Coarse and Fine Filter Elements Installed one Inside the Other in a Single Gas Filter Housing

Statement of the problem. The relevant task of ensuring the uninterrupted operation of modern gas pressure reduction systems is to develop and comprehensively substantiate the possibility of using two-stage filters for natural gas purification in gas reduction points and theoretically substantiate the method for calculating the pressure drop in cylindrical filter elements (CFE). Results. It is proved that when gas flows in the upper cross section of the filter, the pressure drop will be less than in lower cross sections, including the pressure drop in the lowest cross section. This leads to a larger amount of leaking gas, to a larger mass of impurities settling in the lower part of the filter elements of cylindrical coarse and fine cleaning and to a greater degree of their clogging. Therefore, it is recommended to place gas pressure sensors in the lower part of the internal volume of the coarse and fine-cleaned CFE, so that the flow direction of the coarse and finely purified gas washing the sensors at the location of the hole for measuring statistical pressure is tangential to the side surface of the sensor tube. Then the flow direction of the roughly and finely purified gas entering the holes of the sensors is carried out at an angle of 90° and the pressure gauges measure the static pressure. Conclusions. The locations of pressure drop sensors on coarse and fine filter elements installed one inside the other in a single gas filter housing are substantiated. The proposed arrangement of differential pressure sensors will significantly increase the possibility of receiving an earlier signal about the degree of clogging of the gas filter at the control room, as well as have a significant amount of time for timely removal of blockages formed in the coarse cleaning CFE and replacement of fine cleaning CFE.

Development of a direct PMMA-PCB bonding method for low cost and rapid prototyping of microfluidic-based gas analysers.

Rapid prototyping of microfluidic devices requires low cost materials and simple fabrication methods. PMMA and PCB have been used separately for the fabrication of microfluidic devices in a wide range of applications. Although the combined use of PMMA and PCB can have considerable merits, few works have been reported on the direct bonding of these materials. In this work we have investigated the fabrication of microfluidic devices using PMMA and PCB for the analysis of gaseous samples. In order to yield a reliable direct bonding method, four parameters including temperature, pressure, solvent and patterned interface material were experimentally investigated. Results of testing various prototypes showed that a patterned interface of concentric rectangular copper rings exposed to solvent at room temperature and under moderate pressure provided better adhesion strength, sealing and durability. After successful development of the PMMA-PCB direct bonding process, sample prototypes were designed and fabricated to practically assess the combined advantages of two materials. Presented concepts include implementation of heater on a PCB, array of gas sensors coupled with microchannels, serpentine microchannel and fast evaporation of liquid sample using an SMD resistor. It has been shown that advantages of utilizing PMMA such as fabricating the channel easily and with low cost, can be combined with benefits of a PCB including simple sensor installation and the use of copper tracks and electronic components for gas flow modulation. Moreover, it is possible to implement channel, circuit and other electronic components such as microprocessors on a single device.

Distributionally robust risk-resistant synergistic restoration strategy for integrated electricity and gas system with high-fidelity gas dynamic modeling

A synergistic restoration strategy offers a promising solution for expediting restoration of integrated electricity and gas system (IEGS) following blackouts, particularly under the increasing energy interdependence between these two subsystems. However, achieving synergistic restoration is challenging in 1) distinct operational characteristics between electric and gas flow rates, leading to difficulties in accurately modeling the restoration processes with significantly varying system states; 2) potential risks posed by uncertainties, such as fluctuating renewable energy and random contingencies, undermining the effectiveness of restoration strategy. To address these challenges, this paper proposes a novel distributionally robust risk-resistant synergistic restoration strategy for IEGS. Firstly, to accurately capture the dynamics of slow gas flow relative to instantaneous power flow, we propose a high-fidelity linear dynamic gas flow model with multiparametric disaggregation technique, demonstrating satisfactory accuracy in restoration scenarios. Then, the risks by uncertainties of renewable energy and contingencies are handled within distributionally robust framework. Moreover, the IEGS restoration problem is reformulated as a two-stage robust optimization problem by convex conservative approximation and strong duality theory, which is solved by a nested column-and-constraint generation algorithm. Finally, simulation results validate the effectiveness of the proposed restoration strategy, showing the improved restoration efficiency, security, and risk-resistant performance.

Artificial Intelligence Predictions of Biomass Power of an Installed Waste Water Treatment Plant

In the current study, the power generations obtained from gas turbines of an installed waste water treatment plant were predicted, utilizing artificial intelligence method consisting of artificial neural network (ANN). In this regards, a cumulative of 445 data, found in the power generation data cluster and found in the physical and chemical data clusters has been used in the predictions based on the artificial intelligence association method. Each instant data of these total 445 data corresponds to daily average power generation (P) obtained from gas turbines of the facility and corresponds to physical and chemical parameters including the temperature (T), degree of acidity (pH), conductivity (σ), as well as the daily total volumetric flow of the waste gas to be burned at the gas generator (Q). Accordingly, the best prediction obtained by ANN approach was concluded to generate the statistical accuracy results corresponding to 6.1279% mean absolute percentage error (MAPE), 2.1540 MWh/day root mean square error (RMSE), and 0.9730 correlation coefficient (R) for power generation parameter.

Visualization experiment on the ignition performance and flame-spreading in different charging structures

In order to investigate the influence of different charging structures on the ignition performance and its influence on the particle movement before and after the film rupture of the chamber, a visualization experiment platform of the chamber was designed and built, and the stage tests of the ignition of the full particle charging, partial particle charging, mixed before and after the rod-particle charging and the full rod charging were carried out. The experiment shows that the free space will cause the flame propagation speed to increase significantly, from 77 m/s in the charge area to 575 m/s, and there will be pressure fluctuations in several areas of the chamber. The ignition performance of the rod is obviously better than that of the granular, and the pressure fluctuation in the chamber is smaller, the peak ignition gas pressure in the rod charge structure is only 50 % of that in the granular charge structure (1.6 MPa:3.2 MPa), and the maximum pressure difference is only 20 % of that in the granular propellant structure (0.5 MPa:2.5 MPa). The rod-particle mixed charge bed has good ignition consistency in the rod charge area, and when it reaches the granular charge area, the flame will be significantly hindered. The rod basically stays still during the ignition process in the chamber, while the granular will move with the gas flow when there is free space, and after the film is broken, the particle movement is faster than that before the film is broken.

Discharge and mass transfer characteristics of atmospheric pressure gas-solid two-phase gliding arc

Abstract In this work, a gas-solid two-phase gliding arc discharge (GS-GAD) reactor was built. Gliding arc was formed in the gap between the blade electrodes, and solid powder was deposited on the sieve plate positioned beneath the blade electrodes. A range of experimental parameters, including the inter-electrode spacing, gas flow rate, applied voltage, and the type of the powder, were systematically varied to elucidate the influence of solid powder matter on the dynamics of gliding arc discharge (GAD). The discharge images were captured by ICCD and digital camera to investigate the mass transfer characteristics of GS-GAD, and the electrical parameters, such as the effective values of voltage, current, and discharge power were record to reveal the discharge characteristics of GS-GAD. The results demonstrate that powder undergoes spontaneous movement towards the upper region of the gliding arc due to the influence of electric field force. Increasing the discharge voltage, decreasing relative dielectric constant of the powder and reducing the electrode-to-sieve-plate distance all contribute to a greater involvement of powder in the GAD process, subsequently resulting in an enhanced powder concentration within the GAD region. Additionally, powder located beneath the gliding arc experiences downward resistance caused by the opposing gas flow and arc. Excessive gas flow rate notably hampers the powder concentration within the discharge region, and the velocity of powder motion in the upper part of the GAD region is reduced. Under the condition of electrode-to-sieve-plate distance of 30 mm, gas flow rate of 1.5 L/min, and peak-to-peak voltage of 31 kV, the best combination of arc gliding and powder spark discharge phenomena can be achieved with the addition of Al2O3 powder.

Improving computational efficiency in DSMC simulations of vacuum gas dynamics with a fixed number of particles per cell

The present study addresses the challenge of enhancing computational efficiency without compromising accuracy in numerical simulations of vacuum gas dynamics using the direct simulation Monte Carlo (DSMC) method. A technique termed ‘fixed particle per cell (FPPC)’ was employed, which enforces a fixed number of simulator particles across all computational cells. The proposed technique eliminates the need for real-time adjustment of particle weights during simulation, reducing calculation time. Using the SPARTA solver, simulations of rarefied gas flow in a micromixer and rarefied supersonic airflow around a cylinder were conducted to validate the proposed technique. Results demonstrate that applying the FPPC technique effectively reduces computational costs while yielding results comparable to conventional DSMC implementations. Additionally, the application of local grid refinement coupled with the FPPC technique was investigated. The results show that integrating local grid refinement with the FPPC technique enables accurate prediction of flow behaviour in regions with significant gradients. These findings highlight the efficacy of the proposed technique in improving the accuracy and efficiency of numerical simulations of complex vacuum gas dynamics at a reduced computational cost.

Spectroscopic analysis of iron plasma produced by influence of argon gas flow rate on plasma parameter

Spectroscopic analysis of iron plasma produced by influence of argon gas flow rate on plasma parameter

Evaluation of Effective Interfacial Area in a Rotating Packed Bed Equipped with Dual Gas Inlets

This study investigates the effective interfacial area in a novel rotating packed bed (RPB) equipped with dual gas inlets instead of the conventional single-gas-inlet RPB. The aim is to enhance the mass transfer efficiency of gas-liquid contacting processes in RPBs by increasing the number of gas inlets to improve the spread of gas supply into the packing. The RPB is a promising gas-liquid contactor configuration known for its intensified mass transfer characteristics. However, the impact of additional gas inlets on the effective interfacial area of the packing remains unexplored. An experimental method assessed the interfacial area under varying operational conditions which include a liquid flow rate of 0.30-0.60 m3/h, a gas flow rate of 100-300 Nm3/h, and a rotation speed of 600-1000 rpm. At operating conditions covering the maximum rotation speed of 1400 rpm, gas flow and liquid flow rates of 300 Nm3/h and 0.60 m3/h respectively, the results showed that on average, 55 to 97% of the 2400m2/m3 specific packing area can be effectively utilized for gas-liquid mass transfer during separation operations using the RPB. Compared to results reported for single-gas-inlet RPBs using similar packings, the RPB with double gas inlet proved to provide higher utilization of the packing. By simply doubling the number of gas inlets, the findings provide valuable insights into optimizing RPB designs and operations which could enhance mass transfer efficiency for various chemical and environmental applications.

Self-Organizing Sub-μm Surface Structures Stimulated by Microplasma Generated Reactive Species and Short-Pulsed Laser Irradiation.

Catalysts are critical components for chemical reactions in industrial applications. They are able to optimize selectivity, efficiency, and reaction rates, thus enabling more environmentally friendly processes. This work presents a novel approach to catalyst functionalization for the CO2 reduction reaction by combining the reactive species of an atmospheric pressure plasma jet with the electric fields and energy input of a laser. This leads to both a nanoscale structuring as well as a controllable chemical composition of the surface, which are important parameters for optimizing catalyst performance. The treatment is conducted on thin copper layers deposited by high power pulsed magnetron sputtering on silicon wafers. Because atomic oxygen plays a key role in oxidizing copper, two photon absorption fluorescence is used to investigate the atomic oxygen density in the interaction zone of the COST plasma jet and a copper surface. The used atmospheric pressure plasma jet provides an atomic oxygen density at the surface in a distance of 8 mm to the jet nozzle of approximately or a flux of . Pulsed laser-induced dewetting is used to form nanoparticles from the deposited copper layer to enhance catalytic performance. Varying the layer thickness allows control of the size of the particles. A gas flow directed on the sample during the combined treatment disturbs the particle formation. This can be prevented by increasing the laser energy to compensate for the cooling effect of the gas flow. Investigating the surface using X-ray photoemission spectroscopy reveals that the untreated copper layer surface consists mostly of metallic copper and Cu(I) oxide. Irradiating the sample only with the laser did not change the composition. The combination of plasma and laser treatment is able to produce Cu(II) species such as CuO, whose concentration increases with treatment time. The presented process allows the tuning of the ratio of C2O/CuO, which is an interesting parameter for further studies on copper catalyst performance.

Mass transfer of gas–liquid two‐phase flow in asymmetric parallel microchannels with liquid feed splitting

AbstractDue to size limitations, the gas–liquid absorption capacity of a single microchannel is limited, making it difficult to achieve large‐scale CO2 capture. Therefore, the parallel microchannels combining the advantages of high efficiency and large throughput stand out. However, when the operating condition is high gas–liquid flow rate ratio, the liquid phase between bubbles almost disappears after multiple distributions, which affects the amount of gas–liquid absorption. In this study, the numbering‐up of the asymmetric parallel microchannels in the gas–liquid absorption process was investigated by splitting the liquid feed stream in two. The flow patterns under different operating conditions were obtained. The flow and distribution of gas–liquid two‐phase flow were investigated, and the reason of the distribution deterioration caused by appearance of long slug bubbles was explained by the pressure drop distribution. The total liquid mass transfer coefficient and bubble residence time were derived and obtained, and the mass transfer was further discussed.