Rectangular Cross-sectional Shape Research Articles

Effect of nanocavity geometry on nanoscale nucleate boiling heat transfer

In recent years, surfaces with nanocavities have been identified to considerably improve boiling heat transfer, that is highly promising for advanced thermal energy systems. To boost developments in nanostructured boiling surfaces, effects of nanocavity geometry on nucleate boiling at the nanoscale are systematically studied for the first time by utilizing molecular dynamics simulation. Three typical nanocavities with rectangular, semicircular, and triangular cross-sectional shapes are constructed, which have the identical width and depth (8 nm and 4 nm). Moreover, three representative wetting conditions corresponding to different solid-liquid interaction strengths are further considered to provide a comprehensive understanding of geometry effects. The results manifest that nanocavity geometry effect on nucleate boiling can be attributed to the differences in their solid-liquid contact area and solid-liquid interactions play a vital role in reinforcement effectiveness. When the solid-liquid interaction is sufficiently strong (energy coefficient equals 1.5, termed ultra-superhydrophilicity), variations in nanocavity geometries will induce remarkable effects on boiling performance. Among three geometric configurations, the rectangular nanocavity exhibits the highest heat transfer efficiency and achieves maximum boiling enhancement, including significant improvements in bubble nucleation and growth, as well as critical heat flux. This study provides an essential insight into nanoscale boiling reinforcement mechanism.

Perilaku tegangan-regangan beton yang terbuat dari agregat ringan buatan yang diperkuat dengan carbon fiber reinforced polymer

This paper describes the findings of a research study aimed at evaluating the impact of various parameters on the stress-strain behavior of concrete composed of artificial lightweight aggregates with rectangular cross-sections. The factors that were evaluated include the number of fiber-reinforced polymer (FRP) layers, the compressive strength of the concrete, and the cross-sectional shape of the concrete. A total of twenty-two test specimens were fabricated, wrapped with Fiber Reinforced Polymer (FRP), and subjected to concentric compressive loading for experimental evaluation. The experimental findings indicate that Fiber Reinforced Polymer (FRP) demonstrates an excellent wrapping technique for lightweight concrete composed of lightweight aggregate. In addition to this, the test findings indicate a positive correlation between the number of fiber-reinforced polymer (FRP) layers employed and the resultant ultimate stress and strain shown by concrete composed of artificial lightweight aggregate. The test results additionally demonstrate a clear relationship between the rise in ultimate stress and the compressive strength of concrete, while showing an inverse relationship with the ultimate strain observed. Similarly, the test results indicate that the utilization of Fiber Reinforced Polymer (FRP) wrapping has more efficacy when applied to round cross-sectional shapes as opposed to rectangular cross-sectional shapes.

Finite element analysis of a 108-year-old unreinforced brick masonry tower following the 2015 Nepal earthquakes

After a visual inspection following the 2015 Nepal earthquakes, a finite element analysis (FEA) was conducted on a 108-year-old unreinforced brick masonry tower. The focus of study was on the brick masonry clock tower standing at a height of 30.48 m on the Senate Hall (SH) building of Allahabad University in India. This tower, which spans five storeys and features a rectangular cross-sectional shape, exhibits substantial cracks and material degradation across its connections and binding points. The process involved creating geometric plans and a 3D finite-element model through visual inspection and implementing ANSYS Workbench. The study utilised the mechanical properties of the aged materials, sourced from various studies encompassing surveys of old monumental structures, codes, and historical records. The clock tower’s behaviour was assessed through static, modal, and site-specific simulated time history analyses. The static analysis results revealed a maximum deflection of 3.76 mm at the top and a maximum equivalent (von-Mises) stress of 1.81 MPa at the joint of the first-floor level. Modal frequencies for the first three modes were determined to understand the tower’s free vibration behaviour. The time history analyses presented the acceleration, velocity, and displacement response under a peak ground acceleration (PGA) of 1.29 m/s2 simulated for the site. The dynamic analysis highlighted stress responses in critical locations, exposing severe cracks and damages across various points.

Thick film MEMS process using reverse lift-off

The lift-off process is a microfabrication technique that has the capability of forming thin film structures. However, several issues, such as structural shape and burr formation, arise when applying this method to the formation of thick film structures. Thick film structures formed through the lift-off process exhibit a mountainous cross-sectional shape and non-uniform film thickness due to variations in the width of the structure. These challenges make it difficult to apply the method to MEMS. While the reverse lift-off process addresses some of the structural shape problems, its initial development using metal molds makes it challenging to directly apply to MEMS without modification. Therefore, this paper proposes an adaptation to the Si process and presents a method to reduce burrs. The microfabrication characteristics are evaluated by comparing the cross-sectional shapes of thick metallic glass structures formed through both the lift-off and reverse lift-off processes. The structures formed through the reverse lift-off process exhibit a rectangular cross-sectional shape, and the film thickness remains consistent regardless of the structure's width. However, burrs persist on the backside edge of the structure, which hinders its application to MEMS. This paper confirms that pre-etching the underlying Si substrate into an inverse tapered shape effectively reduces burrs. As an illustration of the improved reverse lift-off process applied to MEMS, MEMS mirror structures are fabricated, and their resonance frequency closely aligns with the design value.

Influence of fibre cross-section profile on the multi-physical properties of uni-directional composites

The present work comprehensively examines the influence of fibre-matrix interface perimeter on the multi-physical properties of uni-directional composite materials. Three-dimensional microstructures (containing fibres of triangular, elliptical, rectangular, C-shape and two-lobe cross-section shape) are analysed to evaluate effective thermal conduction, thermo-elastic and piezo-electric properties. Each of these properties is normalised with the respective property of RVE with circular fibre cross-section; These normalised properties are, objectively, compared with the normalised fibre cross-section perimeter (shape factor). For all the considered properties and fibre cross-sectional shapes, a novel observation is that the property experiences a drop (or rise) in the initial range of the shape factor but rises (or drops) monotonically afterwards. This is in contrast with the existing literature observations, where properties are understood to have only a monotonic increase/decrease with the shape factor. Further, it is observed that the magnitude of the initial drop (or rise) is sensitive to the fibre volume fraction and the fibre-matrix property contrast. In accordance with the literature, a strong correlation is observed among the variation of in-plane shear moduli, transverse thermal conduction and transverse dielectric constants.

Prediction of shear strength for CFRP reinforced concrete beams without stirrups

Design guidelines in international codes show noticeable differences with regards to shear strength prediction of concrete beams reinforced with Fiber Reinforced Polymers, (FRP). These discrepancies in shear strength predictions are attributed to many factors affecting the shear behavior, such as shear span/depth ratio (a/d), beam size, rectangular and flanged cross-sectional shape (R-section and T-section), and concrete compressive strength. Shear resistance of beams longitudinally reinforced with carbon FRP, (CFRP), bars is not well defined in the literature compared to beams reinforced with steel bars. This is mainly attributed to the low modulus of elasticity of CFRP compared to traditional steel reinforcement resulting in relatively high strains generated in CFRP reinforcement and consequently wider cracks and lower contribution of the aggregate interlocking mechanism as well as dowel action in shear resistance. This paper numerically investigates the behavior of concrete beams reinforced in flexure with CFRP bars without transverse reinforcement to quantify concrete contribution in shear resistance. Specimens with R and T sections having different shear span-to-depth ratio, concrete compressive strength, and longitudinal CFRP reinforcement ratios are studied to determine the concrete contribution to shear resistance. The nonlinear program ATENA is used to simulate the actual behavior of concrete beams failing in shear and is verified against experimental results gathered from the literature to check the validity of the numerical model. The comparison shows good agreement between experimental and numerical results with a difference of 6% and then a parametric study is conducted to provide a better understanding of the effect of each parameter on the shear behavior of concrete beams reinforced with CFRP bars. The results of numerical models are compared to their counterparts predicted using different equations in codes and guidelines. It is found that the shear capacity of T-section is higher than R-section by about 15% to 25% mainly due to a change in cracking pattern due to the presence of the flange. Furthermore, the shear failure load increased by increasing the longitudinal reinforcement ratio as a result of decreasing strain and enhancement of dowel action. The effect of increasing concrete compressive strength was more pronounced on the shear capacity in arch action as opposed to diagonal tension regions. Finally, an equation is proposed to predict the shear capacity of concrete beams reinforced in flexure with CFRP bars. The shear capacity predicted by the proposed equation provided a good agreement with experimental results for 163 beams with a mean value of 1.01 and COV of 0.17.

Quantitative characterization of liquids flowing in geometrically controlled sub-100nm nanofluidic channels.

With development of nanotechnologies, applications exploiting nanospaces such as single-molecule analysis and high-efficiency separation have been reported, and understanding properties of fluid flows in 101nm to 102nm scale spaces becomes important. Nanofluidics has provided a platform of nanochannels with defined size and geometry, and revealed various unique liquid properties including higher water viscosity with dominant surface effects in 102nm spaces. However, experimental investigation of fluid flows in 101nm spaces is still difficult owing to lack of fabrication procedure for 101nm nanochannels with smooth walls and precisely controlled geometry. In the present study, we established a top-down fabrication process to realize fused-silica nanochannels with 101nm scale size, 100nm roughness and rectangular cross-sectional shape with an aspect ratio of 1. Utilizing a method of mass flowmetry developed by our group, accurate measurements of ultra-low flow rates in sub-100nm nanochannels with sizes of 70nm and 100nm were demonstrated. The results suggested that the viscosity of water in these sub-100nm nanochannels was approximately 5 times higher than that in the bulk, while that of dimethyl sulfoxide was similar to the bulk value. The obtained liquid permeability in the nanochannels can be explained by a hypothesis of loosely structured liquid phase near the wall generated by interactions between the surface silanol groups and protic solvent molecules. The present results suggest the importance of considering the species of solvent, the surface chemical groups, and the size and geometry of nanospaces when designing nanofluidic devices and membranes.

Thermomechanical vibration and stability of effectively homogenized FGM beam with temperature-dependent shear correction factors

Thermomechanical characteristics in the Functionally Graded Materials (FGMs) have been investigated in depth for the precise modeling and analysis of structures in ultimate thermal environments. On this subject, the micro-mechanical interactions of particles in the mixtures of FGMs is necessary to consider the more accurate estimation of structural model. Therefore, the effective material properties are obtained by using homogenization technique based on Mori-Tanaka scheme (MTS) with temperature-dependent material properties. In this regard, present research studies detail temperature-dependent frequencies and thermal buckling behavior of beam model. Then, the physical neutral surface concept is adopted to formulate the decoupled set of stress–strain relations for the FGM models. Also, the First-order Shear Deformation Theory of Beam with rectangular cross-sectional shape including temperature-dependent shear correction factors is developed to improve the practical applications. Furthermore, the results compared with previous data, and the present model is studied in the broad range of temperatures. Specifically, the correlations of shear correction factors and neutral surface shifts are discussed for the models according to temperature and volume fractions. Finally, the thermal stability and the natural frequencies of vibration behaviors are discussed as a result of the mixture ratio for the materials. Furthermore, the mutual interactions of micro-mechanical behavior with the correction factors are especially investigated for thermomechanical analysis.

OPTIMIZATION OF HEAT CONDUCTION FOR TREELIKE NETWORK WITH ARBITRARY CROSS-SECTIONAL SHAPE

To minimize the thermal resistance of the fractal treelike heat conduction network and develop an optimization principle applicable for the network with an arbitrary cross-sectional shape, this paper first establishes a theoretical model regarding the total thermal resistance of the symmetric treelike network with arbitrary cross-sectional shapes and then studies the effects of the geometric and structural parameters of the network on its total thermal resistance. The numerical simulations are also performed to analyze the influences of the geometric and structural parameters of symmetric treelike networks with circular, rectangular and triangular cross-sectional shapes on the total thermal resistance. Both the theoretical model and the numerical simulation show that the total thermal resistance of the network with an arbitrary cross-sectional shape first decreases and then increases with increasing cross-sectional area ratio but always increases with increasing length ratio of branches at two successive branching levels when the total branch volume is constant. When the cross-sectional area ratio is equal to the reciprocal of the branching number, the treelike network has the minimum total thermal resistance. This scaling law is applicable for the treelike network with an arbitrary cross-sectional shape to achieve the minimum total thermal resistance.

Determination of the Actual Stress-Strain Diagram for Undermatching Welded Joint Using DIC and FEM.

This paper presents new methodology for determining the actual stress–strain diagram based on analytical equations, in combination with numerical and experimental data. The first step was to use the 3D digital image correlation (DIC) to estimate true stress–strain diagram by replacing common analytical expression for contraction with measured values. Next step was to estimate the stress concentration by using a new methodology, based on recently introduced analytical expressions and numerical verification by the finite element method (FEM), to obtain actual stress–strain diagrams, as named in this paper. The essence of new methodology is to introduce stress concentration factor into the procedure of actual stress evaluation. New methodology is then applied to determine actual stress–strain diagrams for two undermatched welded joints with different rectangular cross-section and groove shapes, made of martensitic steels X10 CrMoVNb 9-1 and Armox 500T. Results indicated that new methodology is a general one, since it is not dependent on welded joint material and geometry.

Investigation of wind load alteration on rectangular cross-section tall building due to change in relative orientation of interfering building

The alteration of wind pressure distribution caused by the change in relative orientation of a closely located interfering building is studied here on a rectangular cross-sectional shape principal tall building. Interfering building having same cross-sectional shape and height as that of principal building is placed close and in-front of the principal building, with across-wind lengths of two buildings being in-line with each other, keeping one vertical edge of the interfering building in same position the internal angle between principal and interfering building is changed. Two independent type of measurements are undertaken for varying internal angle: (1). Force Measurement (2). Pressure Measurement. For purpose of validation, the results obtained from two independent measurements mentioned are compared later. The results obtained from force measurements are expressed in the form of two-dimensional X-Y plots, while that for pressure measurement are depicted in the form of mean and RMS wind pressure coefficient (CP and CP′) contour plots on all vertical faces of the principal building. It is noted from force measurement, that for internal angle of 00 principal building is fully shielded by the interfering building, in fact a negative drag is observed on the principal building. As the internal angle increases from 00 to 900 the shielding effect caused by the interfering building reduces, as the internal angle further increases from 900 to 1800 a small but uniform increase in along wind force is noted. High magnitudes of across-wind forces and twisting moments are also noted in some cases. Contour plots of mean pressure coefficients give a detailed reason for results obtained with force measurement and also distinctly show the distribution of pressure across vertical faces of the principal building.

Size-dependent vibration and dynamic stability of AFG microbeams immersed in fluid

This paper analyzes the size-dependent vibration and dynamic stability for axially functionally graded (AFG) microbeams immersed in fluid. We consider rectangular and circular cross-section shapes of AFG microbeams. The modified couple stress theory (MCST) is employed to characterize the size dependency of microbeams. The Mori-Tanaka method provides the formulations of material properties with axially continuous gradual variation. The fluid effect on the microbeam is simulated as the added mass. According to the variational principle, we can obtain the governing equations and the boundary conditions of the free vibration and dynamic stability problems. The natural frequency and critical excitation frequency are solved by the differential quadrature (DQ) method and iterative method. Numerical examples present the response of the natural frequency, critical buckling load and critical excitation frequency on the fluid depth, size parameter, fluid density and cross-section shape.

Numerical studies on the hydraulic and thermal performances of trapezoidal microchannel heat sink

The present work numerically studies the hydraulic and thermal performances of trapezoidal microchannel heat sink (TMCHS) with rectangular cross-sectional shape under the constant total channel volume. Considering the flow direction, channel arrangement direction and inlet location, TMCHSs with six different configurations are proposed to compare their hydraulic and thermal performances. The results demonstrate that the pressure drop of the six THCHSs always increases with the decreasing small-to-large end width ratio. For the thermal performance, only the two TMCHSs with Parallel Channel Parallel Flow Large Inlet (PCPFLI) and Reverse Channel Counter Flow Large Inlet (RCCFLI) configurations have improved thermal performances with the decreasing small-to-large end width ratio, including decreasing maximum temperature, decreasing thermal resistance and decreasing center zone temperature difference. On the basis of these, the effects of the channel height and inlet flowrate on the thermal performances of TMCHSs with PCPFLI and PCPFLI configurations are further studied. It is found that PCPFLI and RCCFLI configurations have lower thermal resistance and more uniform temperature distribution with increasing channel height and inlet flowrate. The TMCHS with RCCFLI configuration has the best thermal performances among the six TMCHSs. The findings reported in present work provide a simple method to improve the thermal performances of MCHS by changing the channel shape and configurations.

STUDY OF EDGE PROTECTING ANCHORS INFLUENCE ON SOIL HEAVING OF THE MINE WORKING

To achieve the objective with the claimed technical result, a method of fastening mine workings of predominantly rectangular cross-sectional shape with anchor bolts was used, while the applied task of reducing the heaving of soil rocks is to increase the efficiency of mine workings by ensuring that the mine workings. Ensuring the possibility of reliable and of good quality fortified rocks along the contour of making within the boundaries of the zone of possible collapse of rocks. The length of the soil anchors did not significantly affect the condition of the soil rocks. Consequently, that on the deformations and stresses both in the lateral and in the soils are not soil, but lateral anchors. The use of these technological developments will reduce the cost of conducting and maintaining workings by 7–10% with soil anchors (reducing maintenance costs by 7–10%) and will provide an economic effect of 10–15 thousand tenge per running meter of output.

Influence of non-circular cross section shapes on torsional vibration of a micro-rod based on modified couple stress theory

Torsional micro-rods are key components in many micro-sensors and micro-resonators in aviation industry but in the literature proposed models have usually circular cross section which can be a limitation. In the torsional vibrations of micro-structures with non-circular cross section shape, the displacement fields and governing equations are completely dependent on the cross section shape of the structure which makes the analysis procedure more complicated. The aim of this study is to demonstrate the impact of geometrical parameters of the micro-rod especially its cross section shape, the type of medium and the presence of the external fields such as magnetic field in the torsional vibration behavior of the micro-rod. For this purpose, using the Hamilton's principle, the governing equation of the torsional vibration of the micro-rod with non-circular cross section embedded on elastic medium in the presence of a magnetic field is derived. To show the effects of size dependency of the micro-rod, modified couple stress theory is used. For instance, elliptical and rectangular cross section shapes with the same area are chosen for a micro-rod. After calculating the natural frequency of the micro-rod by the Galerkin method, the effect of cross section shape on the non-dimensional natural frequency of the micro-rod is investigated for changes in the aspect ratio of the cross section. In addition, the influence of length scale parameter, stiffness of torsional medium and magnetic field permeability on the natural frequency of the micro-rod are evaluated. The obtained results demonstrate that the natural frequency of the micro-rod is completely affected by the shape and aspect ratio of the cross section. These results can be useful in the micro-structure design stage. Also, a comparison is made between the obtained analytical results and those of semi-analytical differential transform method (DTM).

Моделирование и исследование различных типов подвесов инерционной массы в чувствительных элементах микромеханических приборов

In microelectromechanical devices and systems (MEMS), capacitive micromechanical accelerometers (MMA) are used in airbag systems, machine vibration monitoring, navigation, seismology, microgravity measurements, etc. The most important structural elements of the sensing element are suspensions, through which the inertial mass is connected to a fixed frame. To ensure reliable operation and stability of sensor parameters, it is necessary to take into account the results of external factors already at the design stage of the sensor structure, especially its sensitive element, and at subsequent stages of the life cycle. In this work, the characteristic structures of suspension elements, which are made of silicon with different crystallographic orientations, are investigated and the results of modeling their most important parameters are presented. The simulation has been performed using the ANSYS program. The natural frequencies of inertial mass oscillations, residual mechanical stresses in the structural elements of silicon sensitive element with different crystallographic orientations have been calculated upon impact (up to 10 000 g). The natural vibration frequency changes and the dynamics of the change in the residual mechanical stress in the suspension elements with a temperature change in the range from +150 to –150 °C for a short time interval of 10 s, which corresponds to thermal shock, investigated. The results of studies of residual mechanical stresses arising upon impact and natural frequencies of inertial mass oscillations have been made it possible to develop recommendations on the choice of the design of suspension elements made of silicon, providing high sensitivity and stability of MMA parameters. It has been established that the use of folded springs with a rectangular or round cross-sectional shape with a suspension element thickness of 40 μm provides the highest temperature stability of the parameters. The results obtained are useful for developing real designs of MMA and other micromechanical devices

SMEAR LAYER REDUCTION IN ROOT CANALS PREPARED WITH TRIANGULAR AND RECTANGULAR FILES AS EVALUATED BY SCANNING ELECTRON MICROSCOPY

Objective: Root canal preparation procedures can produce a smear layer when in contact with the root canal wall, which can result in treatmentfailure. As such, the cross-section shape of the file may influence the production of smear layer. In this study, we compared the smear layer productionat the apical third of the root canal wall between files with a triangular or rectangular cross-section shape.Methods: Thirty-two human premolar samples taken from mandibles were divided into two groups whose root canals were prepared using fileswith either a triangular (One Curve®, n=16) or rectangular (Hyflex EDM®, n=16) cross-section shape. After preparation, the root canals were irrigatedwith a combination of 2.5% NaOCl and 17% ethylenediaminetetraacetic acid (EDTA). The smear layers in the apical third of the root canal walls wereobserved using a scanning electron microscope and quantified according to the Foschi scoring system.Results: The Mann–Whitney U-test revealed a significant difference between root canal preparations using the different file shapes. The groupprepared with the triangular file produced lower smear layer scores compared with the group prepared with the rectangular file.Conclusion: Root canal preparations using files with different cross-section shapes (e.g., triangular and rectangular), followed by irrigation with 2.5%NaOCl and 17% EDTA, produced smear layers in the apical third area. However, root canal preparations using files with a triangular cross-sectionshape were shown to reduce smear layer production compared with files with a rectangular cross-section shape

Numerical Studies on the Thermal Performances of Electroosmotic Flow in Y-Shaped Microchannel Heat Sink

This paper numerically studies the thermal performances of electroosmotic flow (EOF) in a symmetric Y-shaped microchannel heat sink (MCHS) having a constant total channel surface area, that is, constant convective heat transfer area. It is found that the average convective heat transfer coefficient of EOF increases with the increasing driven voltage, which is attributed to the increase of EOF flowrate with the increasing driven voltage. However, the maximum MCHS temperature shows an increasing after decreasing trend with the driven voltage owing to the dramatically increasing Joule heating when the voltage is large enough. Further, both the maximum MCHS temperature and average convective heat transfer coefficient are sensitive to the cross-sectional dimensions of the Y-shaped microchannels. The thermal performances of EOF in the Y-shaped MCHS show a strengthening to weakening trend with the increasing daughter-to-parent channel diameter ratio of the Y-shaped microchannel with circular cross-sectional shape, and show a similar strengthening to weakening trend with the increasing daughter-to-parent channel width ratio and the increasing microchannel height of the Y-shaped microchannel with rectangular cross-sectional shape. These cross-sectional dimension dependences of thermal performances are related to the increasing to decreasing trend of EOF flowrate changing with the microchannel cross-sectional dimensions.

Effect of profile and reinforcing the surface layers on bending behavior of 3D multi-cell spacer weft-knitted composites

3D multi-cell spacer-knitted reinforced composites are composed of knitted layers which are joined together by multiple fabric connecting layers. Despite numerous capabilities, they demonstrate inferior bending performance due to their highly looped construction as well as low fiber volume fraction. Bending characteristics could be enhanced by inserting the warp and weft yarns through the fabric’s surface layers in wale and course directions. This research aims to investigate the role of reinforcing warp and weft yarns and structure profile on bending behavior of the composites produced from 3D multi-cell spacer-knitted fabrics. 3D multi-cell spacer-knitted fabrics were produced with rectangular cross-sectional shape in single- and double-decker profiles on a computerized flat-knitting machine. The surface layers of both 3D multi-cell spacer-knitted fabrics were reinforced by glass straight yarns in course and wale directions. The produced fabrics were used to fabricate thermoset 3D composites using epoxy resin via vacuum-assisted resin-transfer method. Composite samples were subjected to three-point bending load. Statistical analysis revealed that the composite profile and presence of the reinforcing warp and weft yarns affect significantly the flexural properties of 3D-knitted composites. Accordingly, introduction of the reinforcing straight yarns causes an increase in maximum bending force by 75 and 62.5% for single and double-decker structures, respectively. In order to understand how the tensile and compressive stresses are distributed on the 3D-knitted composite structure as well as to predict their mechanical behavior, a macro-mechanical model was created in the ABAQUS software.

3D investigation of the channel cross-section configuration effect on the power delivered by PEMFCs with straight channels

In the present study, a three-dimensional (CFD) model is performed to investigate the effects of the channel cross-section shape on power density, pressure drop and local transport phenomena of the single straight channel PEMFC. 30 forms of channel cross-section including 5 well-known and 25 new innovative channel cross-section configurations have been investigated using ANSYS-FLUENT. The carried out experimental and numerical validations to verify the present model accuracy have shown a good agreement. The channel cross-section shapes have a significant influence on the power density at medium and higher current density. The best performance is reported by the channel cross-section configuration that has a trapezoidal bottom shape and an inverted trapezoidal top form. Whereas, the worst performance is obtained by the channel cross-section configuration that has an inverted half elliptical bottom shape and an inverted trapezoidal top form. A bad choice of the channel cross-section configuration can lead to a power density loss of 4.65%. The largest pressure drop is obtained from the triangular channel cross-section form whereas; the smallest pressure drop is reported by the rectangular channel cross-section shape.