Unit Pressure Drop Research Articles

Multiple-factor analysis of dehumidification performance and flow resistance for the cross-flow membrane module based on orthogonal test

In this study, the multiple-factor analysis of dehumidification performance and flow resistance for the cross-flow membrane module was carried out based on the orthogonal test. Three operating and four structural parameters were selected as the independent variables for two test indicators, i.e., dehumidification rate (γ) and dehumidification account of per unit pressure drop (Δφ/Δp). The influence of seven factors on the test indicators was ranked by the single factor analysis of range. The results indicated that the inlet velocity of humid air, u in, has the most important influence on γ and Δφ/Δp. Among the structural parameters of membrane module, the fiber length has the greatest impact on γ while that is the ratio of fiber pitch to fiber outer radius for Δφ/Δp. The empirical correlations of γ and Δφ/Δp were obtained by the regression analysis of simulated data, which help to predict the dehumidification performance and flow resistance of membrane systems from known structural parameters and operating conditions. According to plus or minus of the fitted exponents, the influences of seven factors on the two indexes are different. The better dehumidification performance and less flow resistance can be achieved by appropriately increasing w in and l of the membrane module. This study is of guiding significance in the structure optimization of membrane modules.

Numerical Investigation on the Heat Transfer Characteristics of Liquid Lithium Metal in a Bent Tube and Its Structure Optimization

Abstract Liquid lithium is expected to be the promising coolant for the next generation of space nuclear reactor power sources, and pipe structures have critical impacts on the flow and heat transfer characteristics, whereas related studies are still incomplete. In this work, a steady-state non-isothermal heat transfer model with modified turbulent Prandtl number is developed for the turbulent flow of liquid lithium in elbows with different bends. The results demonstrate that liquid lithium has best performance in a 90 deg bend in the Pe range of 320–955, which has the highest heat transfer performance per unit pressure drop and exhibits the lowest entropy generation. Due to the difference in flow velocity between the inner and outer sides of the pipe, a high-temperature region exists in the inner-wall area from the pipe bend and migrates from the wall side to the center area in the exit area. When decreasing the flow velocity and increasing the wall heat flow density, a more significant increase in the percentage of the high-temperature region is demonstrated on the inner wall side of the pipe in the exit area of the bend. Under a given total length of L, the inlet length H with the H/L ratio of 0.025 has the minimum entropy generation within the unit pressure drop, and is the best U-tube structure. This work provides comprehensive investigations on flow and heat transfer characteristics of liquid lithium in bends and U-tubes and inspires practical applications.

Numerical simulation research on two-phase flow boiling heat transfer in helically coiled tube

In this paper, the partial geometric models of helically coiled tube type heat exchanger with different tube diameters (d = 12, 19, 25 mm), tube pitches (P = 50, 100, 150 mm) and helical radius (R = 100, 150, 200 mm), were established. Numerical simulation and performance comparison were carried out using water and water vapor as the working fluid. The gas–liquid phase distribution in the helically coiled tube, the gas volume fraction at different cross-sections, and the changes of heat transfer coefficient and pressure drop along the length of the helically coiled tube were analyzed. The results showed that the gas phase was concentrated in the inner side (near the side of the central axis) and the upper side of the helically coiled tube under boiling condition, and the liquid phase was concentrated in the bottom of the helically coiled tube and is stratified with the gas phase. As the helical radius and tube diameters increased, the heat transfer coefficient and unit pressure drop decreased gradually. Based on the simulated data, the boiling heat transfer correlation was fitted by the method of multiple nonlinear regression, and the mean absolute error was 4.5% compared with the modified Chen's correlation. Therefore, the numerical results were correct and trustable.

Global sensitivity analysis and optimization for coal–water slurry preheaters based on metamodel of optimal prognosis

Enhancing energy efficiency by coal–water slurry preheaters in the gasification process, the geometry of ladder-type fold helical baffles and shell–inlet velocity have an important effect on thermo-hydraulic performance of preheaters. A variance-based global sensitivity analysis procedure was built by metamodel of prognosis, and optimization results were compared between genetic algorithm and particle swarm optimization. The simulation results illustrate that heat transfer coefficient per unit pressure drop (K/ΔP) increases when folding angle and folding ratio increase, and K/ΔP decreases with increasing relative height and shell–inlet velocity. As for K/ΔP, the coefficient of prognosis of full model is 99.03%, and total effects of shell–inlet velocity, folding angle, folding ratio and relative height is 70.34%, 25.01%, 8.74%, and 7.87%, respectively. Based on reduced spaces with most influential parameters, optimization cases show genetic algorithm is more efficient and provides better results, folding angle, folding ratio, relative height and shell–inlet velocity are 50°, 0.6, 0.5 and 1.4 m s–1 when maximizing K/ΔP. The research results provide theoretical guidance for selection, design and optimization of coal–water slurry preheaters.

Heat transfer and flow characteristics of straight-type PCHEs with rectangular channels of different widths

Printed circuit heat exchanger (PCHE) is considered to be the most promising heat exchangers in the supercritical CO2 Brayton cycle. The heat transfer and flow characteristics in straight-type PCHEs with rectangular channels of different widths were numerically investigated in this paper. With the increase of rectangular channel width, the average heat transfer coefficients in the cold side decrease first and then increase, while the average heat transfer coefficients in the hot side always increase. The increase of rectangular channel width can effectively increase the heat transfer rate per unit volume and reduce the pressure drop at the same mass flux. However, the changes of heat transfer rate per unit volume and pressure drop tend to be gentle with the width increase. Furthermore, the overall performance evaluation of PCHEs with rectangular channels of different widths was performed. The overall performance evaluations of rectangular channels in the hot side of PCHEs are enhanced compared with the semicircular channel, and the enhancement becomes more and more significant with the increase of mass flux. While the overall performance evaluations of the rectangular channels in the cold side are not as good as that of the semicircular channel. The channel width should be appropriately increased in the hot channel design of straight-type PCHEs to reduce flow resistance and improve overall performance evaluation. The sharp corners of the PCHE channel cross-sections should be eliminated to reduce the heat transfer deterioration zone.

Flow characteristics of pneumatic conveying of stiff shotcrete based on CFD-DEM method

To reveal the flow characteristics of materials in the pneumatic transportation of stiff shotcrete, based on the CFD-DEM coupling simulation method, the numerical simulation of gas-solid flow of stiff shotcrete materials in the pipeline transportation process was carried out. The discrete element simulation parameters of stiff shotcrete are obtained by parameter calibration. In addition, the accuracy of the simulation results is proved by field experiments. The results show that the pressure drop area in the acceleration section is 2 m before the initial stage of pneumatic conveying. With the increase of gas velocity and feed rate, the unit pressure drop increases, and the most worn area position at the elbow is always about 30°. The linear relationship between unit pressure drop and gas-solid ratio is obtained. This paper can provide reference and optimization for the research of long-distance pneumatic conveying system of stiff shotcrete materials.

Optimization design of helical micro fin tubes based on exergy destruction minimization principle

• Increased heat exchange area and the secondary flow are the primary sources of heat transfer enhancement. • The local exergy destruction rates are related to the equivalent heat transfer coefficient and the unit pressure drop. • Optimal design tends to have a larger number of starts and a lower micro fin height. • The exergy destruction minimization principle is proved to be still applicable in the case of the periodic model and fully developed turbulence. The helical micro fin tubes (HFT) are commonly used in various double pipe heat exchangers because of the excellent processing and anti-fouling performance. It is of great significance to further improve the overall efficiency of the HFT so as to diminish energy consumption. In this work, the heat transfer and flow characteristics of the HFT are studied by numerical simulation. The results show that the heat transfer enhancement factors of the HFT are the secondary flow generated near the wall and the increase of the heat exchange area. In addition, the effects of the geometrical parameters on thermal–hydraulic performance are studied at Re = 36,636. It is found that the micro fin height ( e ), the helical angle ( φ ), and the number of starts ( Ns ) have a significant impact on the overall performance, and there is a strong mutual coupling between them. According to the parametric analysis, the HFT with a low micro fin height and a large number of starts is considered to be a better geometrical type. Finally, in order to select (or design) the HFT quickly under the specific working conditions, based on the exergy destruction minimization principle, the geometrical parameters are optimized by using the artificial neural network and genetic algorithm. An optimal solution ( e = 0.23 mm, φ = 36.1°, and Ns = 66) is selected from the Pareto front by the TOPSIS method. The results indicate that the optimal solution has a sensible balance between the exergy destruction caused by heat transfer and fluid flow. Besides, it has a better thermal–hydraulic performance as well ( PEC = 1.73). This work fills the gap of heat transfer and the geometrical optimization study of HFT based on the second law of thermodynamics and provides strong evidence that the exergy destruction minimization principle is still applicable in the case of the periodic model and fully developed turbulence. We hope that it will be contributed to the structural design of the HFT.

Numerical study on flow, heat transfer and mixing of highly viscous non-newtonian fluid in Sulzer mixer reactor

Computational fluid dynamics (CFD) was applied to investigate the laminar hydrodynamics, heat transfer and mixing of highly viscous non-Newtonian fluid in Sulzer mixer reactor (SMR). The CFD model was validated with the heat transfer and tracer trajectory experiment. Herschel-Bulkley model was adopted to describe the complicated rheological properties of pseudoplastic and Bingham-pseudoplastic fluids. The increase of rheological parameters, i.e. the yield stress, the consistency index and the power-law index, will lead to higher viscosity and more power consumption in shell side. The yield stress and the power-law index were found to have significant effect on the shear distribution, residence time distribution characteristics and mixing efficiency, while the consistency index has little influence. The heat transfer performance and mixing efficiency can be improved by increasing the inlet velocity, and the heat transfer performance is not sensitive to the rheological parameters at low inlet velocities. The advantages of SMR in dealing with highly viscous non-Newtonian fluid were studied by comparing to the straight tube heat exchanger (STHE). The fluid elongation and effective radial mixing in SMR greatly improve the heat transfer performance and mixing efficiency. The Nusselt number per unit pressure drop of SMR is about 1.1–1.8 times as those of STHE, indicating SMR has better comprehensive performance.

Design and Analysis of Various Baffle System in Shell Tube Heat Exchanger

Heat exchangers are systems of thermal engineering in which its applications are occurred in different industries. Heat exchangers are the basic or heart of once organized plant since it transfers energy to the processing plant Shell and tube heat exchanger is the most common type heat exchanger widely use in refinery and other chemical process, because it suits high pressure application. The process in solving simulation consists of modeling and meshing the basic geometry of shell and tube heat exchanger using CFD package ANSYS 18.0. The objective of the project is design of shell and tube heat exchanger with various baffle structure and study the flow and temperature field inside the shell using ANSYS software tools. The heat exchanger with single, double, and with 10 and 20 degree inclined baffle will be defined. In simulation will show how the pressure varies in shell due to different double baffle angle and flow rate. The flow pattern in the shell side of the heat exchanger with angled baffles was forced to which results in a significant increase in heat transfer coefficient per unit pressure drop in the heat exchanger.

An Investigation of baffle angles on Shell and Tube heat exchanger

The turn of events and execution enhancement of shell and tube heat exchanger is an issue of incredible test and part of arising early innovation. The exhibition enhancement would serve an extraordinary commitment to assuage the swelled working expenses just as energy emergency. This paper grandstands every one of the experimental outcomes got from the constant framework investigation in different working conditions. Further it addresses examination for a few shell-and-tube heat exchangers with segmental confounds with various point parametric variety. The framework distinguishing proof has been done utilizing CFD investigation. The consolidated outcomes as for same shell-side stream rate show that, the heat move co-proficient of the heat exchanger with astounds is higher than that of the heat exchanger without perplexes, while the shell-side pressing factor drop of the previous is even a lot of lower than that of the last mentioned. Further upgrade methods ought to be consolidated to improve shell-side heat move dependent on a similar stream rate. The near investigation of heat move coefficient per unit pressure drop shows that the Segmental Baffle Heat exchanger have critical execution advantage over Segmental Baffle Heat exchanger for similar mathematical arrangements.

Reserve Estimation from Early Time Production Data in Geopressured Gas Reservoir: Gas Production of Cumulative Unit Pressure Drop Method

There is high uncertainty in reserve estimation during the early development of deep ultrahigh pressure gas reservoirs, largely because it remains challenging in accurately determining the formation compressibility. To overcome this, starting from the definition of compressibility, a novel gas production of cumulative unit pressure drop analysis method was established, of which the effectiveness was proven by applications in calculating the reserves of three gas reservoirs. It has been found that, in the limiting case, i.e., when the formation pressure dropped to the normal atmospheric pressure, the dimensionless gas production of the cumulative unit pressure drop was the reciprocal of the initial formation pressure. Besides, the relationship curve of the dimensionless gas production of the cumulative unit pressure drop and pressure drop was a straight line in the medium term, extending the straight line and intersecting the vertical line passing through the original formation pressure point, and the reserves can be determined according to the intersection point and the initial formation pressure. However, due to the influence of natural gas properties, the value needs further correction, and the correction coefficient depends on the pseudocritical temperature of natural gas. Specifically, when the pseudocritical temperature is given, the correction coefficient would be close to the minimum value of the natural gas deviation factor. When the pseudocritical temperature is more than 1.9 and less than 3.0, the minimum deviation factor would be between 0.90 and 1.0, and the higher the pseudocritical temperature, the closer the ratio is to 1.0.

Effect of ambient pressure on gas adsorption characteristics of residual coal in abandoned underground coal mines

To study the influence of ambient pressure on gas adsorption of residual coal and provide a basis for establishing a reasonable calculation model of gas resource adsorbed in residual coal in abandoned underground coal mines, the residual coal was divided into loose-type residual coal and column-type residual coal after an analysis on the ambient gas pressure variation process. Then the gas adsorption experiments were conducted under adsorption equilibrium pressure range of 0.5–2.5 MPa using a self-made experimental device. The results show that (1) In the range of 0.5–2.5 MPa, the amount of methane adsorption in the loose-type residual coal under the intense replenishment condition can be 19.5% less than that under the gradual replenishment condition. (2) With a continuous decrease in ambient pressure, the methane adsorption amount in the column-type coal is reduced. The adsorption capacity at a unit pressure drop gradually increases from a minimum of 0.24 mL▪g-1 × 0.1 MPa−1 to a maximum of 2.375 mL▪g-1× 0.1 MPa−1. The initial adsorption equilibrium pressure shows little effect on the methane adsorption in column-type residual coal. (3) The bigger difference of the methane adsorption amount, with a maximum of 2.347 mL▪g-1, between the loose-type residual coal and column-type residual coal under the intense replenishment condition can be observed in the pressure range of 0.8–1.2 MPa. Therefore, the coal type should be considered to establish a gas storage model of residual coal in abandoned coal mines.

Evaluation of pipeline networks to predict an increase in crude oil flow rate

The purpose of this paper is to investigate the role of pipeline arrangement in the oil industry, especially for crude oil transportation. The need often arises for increasing the flow rate per unit pressure drop in pipelines. The usual and most economical solution to the problem is to place one or more lines parallel to the original, either partially or throughout the entire length. This paper evaluates this subject by considering the economic aspects. In this work, a single pipeline with length, L = 20000 m and inside diameter D1 = 0.5 m was considered, and three types of pipeline networks include parallel, series, and looped were compared with the single pipe. According to the results, the parallel network has the best performance in comparison with the other pipeline networks, but it needs high costs. The results showed that for the series pipeline, in constant diameter ratio (D2/D1), flow capacity increased by increasing fraction of length (L2/L). For the parallel pipeline, gain coefficient (G=QtQsingle ) increased exponentially with the diameter ratio. This study also showed that in a constant diameter ratio (D2/D1), by increasing L1/L, the gain coefficient increased in the looped pipeline. The results presented in this paper can allow researchers and engineers to evaluate and predict the oil flow rate in network pipelines.

Change laws of water invasion performance in fractured–porous water-bearing gas reservoirs and key parameter calculation methods

In order to develop fractured–porous water-bearing gas reservoirs efficiently, it is necessary to understand the change laws of water invasion performance. Based on the π theorem, this paper adopted the dimensionless parameter that can reflect the change characteristics of water invasion performance to design the physical simulation experimental scheme of water invasion performance. The full-diameter cores taken from the reservoir of one certain fractured–porous water-bearing gas reservoir in the central Sichuan Basin were selected to carry out physical simulation experiment of water invasion performance. Then, by virtue of numerical inversion, the experimental results were converted into evaluation parameters of water invasion performance in water-bearing gas reservoirs. Afterwards, the change laws of water invasion performance in fractured–porous water bearing gas reservoirs were investigated, and the method for calculating key water invasion performance evaluation parameters and water volume was established. Finally, water invasion performance analysis and aquifer size evaluation were conducted with the Xu 2 Member gas reservoir, Upper Triassic in the Zhongba gas field of the Sichuan Basin as an example. And the following research results are obtained. First, in fractured–porous gas reservoirs with edge and bottom water, water invasion and gas production occur simultaneously. Before water production, there is a linear relationship between bottom hole pressure and reserve degree of reserve recovery. After water production, water invasion speeds up and the water–gas ratio (WGR) rises rapidly and finally approaches to a stable WGR of higher level. Second, the bottom hole pressure drop rate before water production and the stable WGR are mainly affected by the water volume, and the degree of reserve recovery per unit pressure drop and the stable WGR can be used to evaluate the water volume. Third, a method for mutual interpretation and evaluation of the aquifer size and the reserve degree of reserve recovery per unit pressure drop before water production and the stable WGR of fractured–porous gas reservoirs with edge and bottom water is established. In conclusion, the water invasion performance curve of the gas reservoir agrees with the core simulation experimental results. Based on the known water volume of a gas reservoir, the stable reserve degree of reserve recovery per unit pressure drop before water production and the stable WGR can be predicted; and on the basis of the stable WGR, the water volume of a gas reservoir can be predicted. The prediction results are in line with the production performance, providing a theoretical support for water invasion performance prediction and overall water control of fractured–porous water-bearing gas reservoirs.

Natural convection solar air heater: Bell-mouth integrated converging channel for high flow applications

The bulk movement of fluid in natural convection solar air heater (SAH) is generated due to density variation and hence suffers from lower mass flow rates. Mounting additional surfaces/fins in SAH duct enhances the thermal characteristics, however, it comes at the cost of hydraulic performance. This limits the device usage in buildings and other high flow rate applications. In the present study, two new designs of SAH were numerically analyzed are: (a) taper flow passage for better thermal performance; (b) tapered designs incorporated with bell-mouth inlet opening for improved hydraulic performance. Parametric design analysis was conducted for large range of taper ratio and bell-mouth ratio. The results show that the tapered design is about 70% thermally more effective and about 6% higher Nusselt number per unit pressure drop than conventional SAH. A significant enhancement in hydraulic performance of more than 300% was observed when bell-shaped inlet design was integrated with the tapered designs. An independent correlation for Nusselt number variation has been developed as a function of Rayleigh number and tapper ratio. Predictions from the developed correlation is in excellent following with the numerical data.

Connotations of scientific development of giant gas fields in China

A giant gas field refers to a gas field with proved geological reserves of natural gas more than 30 billion cubic meters, peak annual output of natural gas more than 1 billion cubic meters, and a certain plateau period. It is an important foundation for the rapid growth of China's natural gas reserves and production and its long-term stable development in the future. And it is also the key to ensure the security of gas supply. By systematically analyzing the development practice of more than 260 gas fields at home and abroad and dissecting and simulating typical gas fields, this paper comprehensively studied the connotation, core technology and whole life cycle index system on the scientific development of giant gas fields. It is indicated that the scientific development connotation of giant gas fields consists of the following parts. First, the natural gas development concept with “water identification, control and treatment” as the technical system is put forward. That is to carry out “water-control development” in conventional gas fields and hydraulic fracturing development in unconventional gas fields. A reasonable gas production rate should be set according to the types and characteristics of gas reservoirs. Second, economic and social benefits of gas field development should be evaluated comprehensively to ensure its long-term stable production. Third, the suitable production stabilization mode shall be adopted according to the production characteristics of gas wells and the development characteristics of reservoirs. Fourth, the recoverable reserves of a gas field, the development laws of formation water and artificial water flooding, the ultimate recovery technological countermeasures of the gas field, the cost-effective stable period of the gas field should be determined based on the fine description of conventional and unconventional gas reservoirs in different stages, the development characteristics of gas reservoirs and the monitoring results of production performance. The core technologies in the scientific development of giant gas fields include large-scale optimization technology, scientific well arrangement technology, balanced production technology and deep potential tapping technology. Based on this, several parameters are selected comprehensively as the key indexes for the scientific development of giant gas fields, such as production rate, pressure drop, degree of reserves recovery and output per unit pressure drop, and the whole life cycle index systems for four types of gas reservoirs are established, i.e., high-pressure gas reservoirs, low-permeability and tight gas reservoirs, fractured–porous reservoirs, and shale gas reservoirs. In conclusion, the research results enrich and improve the theories of natural gas development geology and are conducive to guiding the scientific development of different-type giant gas fields, thus further promoting the rapid development of natural gas industry in China.

Investigation of the thermal-hydraulic characteristics in the shell side of heat exchanger with quatrefoil perforated plate

Quatrefoil perforated plate (QPP) is a kind of whole circular support plate for the shell side of shell-and-tube heat exchanger (STHX), and the design and optimization of heat exchanger with this support structure are the key technologies to study and improve the performance of heat exchanger. The influences of the hole height and plate spacing of the QPP on the thermal-hydraulic performance of the heat exchanger were studied mainly by using computational fluid dynamics (CFD) method. And the reliability and accuracy of the numerical results were verified by compared with experimental results. With Reynolds number varying from 5000 to 20,000, the results show that the heat transfer coefficient and pressure drop in the shell side of the heat exchanger both increase with the decrease of the hole height and the plate spacing of the QPP, but the shell side heat transfer coefficient per unit pressure drop h/Δp decreases. Under the conditions of the same fluid flow rate and same plate spacing, compared with segmental baffle heat exchanger, the comprehensive performance h/Δp of heat exchanger with QPPs is improved by 27%–41%. The empirical correlations for Nusselt number and pressure drop in the shell side of heat exchanger with QPPs were obtained and the calculation deviation of correlations both are within ±10%, which can be used to guide engineering design and practice.

Experimental investigation on shell-side performance of a novel shell and tube oil cooler with twisted oval tubes

The lubrication oil cooler is widely used in many industries. The lubrication oil is usually operated in a laminar state with Reynolds number less than 1000 due to its high viscosity characteristic. It is hard to augment the heat transfer performance of high viscosity fluids without obvious pressure drop. A lot of researches have been conducted on the shell-side heat transfer and fluid flow characteristics of twisted oval tube heat exchangers. However, the previous study mainly focused on the high Reynolds number regime and the correlations obtained are not suitable for low Reynolds flow. In the present paper, a novel self-supported shell-and-tube oil cooler with twisted oval tube bundles (OCTT) is designed. Experiments are conducted to investigate the shell-side heat transfer and pressure drop of OCTT compared to the conventional shell-and-tube oil cooler with round tube bundles (OCRT) in low Reynolds number flow. The experimental results indicate that at identical oil volume flow rate, the shell-side pressure drop of OCTT is lower than that of OCRT. Furthermore the shell-side heat transfer coefficient per unit pressure drop of OCTT is larger than OCRT. The empirical equations for Nusselt number and friction coefficient of OCTT in low Reynolds number ranging of 50–600 are also deduced from the experimental data, which could provide a beneficial guidance for the design of OCTT.

The permeability of replicated microcellular structures in the Darcy regime

AbstractThis study provides an extension to previously published articles on measurements and computational fluid dynamic (CFD) modeling and simulations of airflow across “bottleneck‐type” structures in the Forchheimer regime to purely inertial‐neglected (Darcy regime) incompressible flowing fluid via tomography datasets. A linear‐dependent relationship between the CFD computed unit pressure drop developed across the samples and the superficial fluid inlet velocity was observed for all the samples for creeping fluid flow (0–7 × 10−03m·s−1). The permeability of the structures was observed to be dependent on the structural parameters of the porous medium and most importantly, its pore diameter openings. Linear graphical relations between permeability and pore‐structure related properties of these materials were observed and these could assist in minimizing the number of design iterations needed for the processing of self‐supporting porous metals.

Performance evaluation of mass transport enhancement in novel dual-channel design of micro-reactors

Various design configurations of semi-T-shaped dual-channel micro-reactors were numerically examined for their laminar mass transport performance in heterogeneous catalytic combustion of methane and air. One single-channel and five dual-channel configurations (i.e., parallel, divergent, convergent, zig-zag, and curved configurations) were investigated with a two-dimensional computational fluid dynamics model. These innovative design configuration were compared in terms of CH4 utilization, pressure drop, CO/CO2 ratio, catalyst utilization, and a performance index at various Reynolds numbers. Dual-channel micro-reactors were found to enhance mass transport due to the well mixed flow and the increased reaction contact area. By suitably modifying the dual-channel layout angle and shape, recirculation zones can be formed within the reactor which increase CH4 utilization. However, the improved conversion rate is achieved at the cost of high pressure drop. The parallel dual-channel design provides the highest conversion per unit pressure drop over the range of the Reynolds numbers studied. For Reynolds numbers of 20 and 40, compared to the single-channel micro-reactor, divergent, convergent and curved channel designs yield higher conversion per unit pumping power. However, further increase of Reynolds number (i.e., 60, 80, and 100) deteriorates their performance due to the significantly increased pressure drop and shorter residence time.