Progress in Computational Fluid Dynamics, An International Journal (28 papers in press)

Regular Issues

• Numerical investigations on the performance of Darrieus vertical axis wind turbine with NACA0017 blade profile  
  by Satyajit Das Karmakar, Syed Rahman, HIMADRI CHATTOPADHYAY 
  Abstract: The selection of effective blade profile for vertical axis wind turbines is an important criterion for harnessing wind energy. In this paper, transient simulation of Darrieus lift type turbine having NACA0017 blade profile is reported. URANS equations are solved with SST K
  Keywords: vertical axis wind turbine; NACA0017 airfoil shape; performance enhancement; power coefficient; URANS.
  DOI: 10.1504/PCFD.2022.10048848
   
  
• Comparison between variable forcing techniques of the lattice Boltzmann method for turbulent flow simulations  
  by Waleed Abdel Kareem, Hadeer Mohamed 
  Abstract: A comparison between different forcing techniques of the lattice Boltzmann method (LBM) is carried out for isotropic turbulence with resolutions of 1283 and 2563 , respectively. Four forcing techniques are investigated with the lattice Boltzmann D3Q19 model. Few forcing methods were suggested to add a force term to the lattice Boltzmann method (LBM) but they are neither tested nor compared for box turbulence. The first technique is performed by adding the constant force randomly to the collision term. The second is depending on shifting the velocity field. The third technique is achieved by adding the force to the collision term with shifting the velocity field. The fourth technique considered the discrete lattice effects where a forcing function with consistent moments of the hydrodynamics equations is added to the collision operator with shifting the velocity field. Results show that the obtained turbulent velocity fields yield universal characteristics similar to previous studies.
  Keywords: homogeneous isotropic turbulence; HIT; lattice Boltzmann method; LBM; tube-like vortices; variable forcing techniques.
  DOI: 10.1504/PCFD.2022.10048996
   
  
• Dynamics of Taylor Bubbles in non-Newtonian Shear Thinning Continuous Phase  
  by Shilpi Chatterjee, Abhiram Hens, Kartik Chandra Ghanta, G. Biswas 
  Abstract: Droplet-based microfluidics has emerged as an efficient platform in a number of lab-on-chip devices for chemical or biomedical analysis. In most of such applications, a non-Newtonian complex liquid constitutes the continuous phase. In the present study, a two-phase gas
  Keywords: Taylor bubble; multiphase flow; microchannel; CFD; pressure drop.
  DOI: 10.1504/PCFD.2022.10049300
   
  
• An improved alternative weighted essentially non-oscillatory scheme for conservation laws  
  by Uttam Rajput, Krishna SINGH 
  Abstract: In the present study, a fifth-order improved alternative weighted essentially non-oscillatory scheme has been developed for non-linear hyperbolic conservation laws. We have proposed an improved fifth-order smoothness indicator to design the present scheme. Further, the numerical flux evaluation is based on the reconstruction of primitive variables rather than conservative variables. The third-order TVD Runge-Kutta method has been used for the time advancement of the solution. The computations have been performed for various one, two, and three-dimensional test cases. Numerical results are compared with the exact solution and results with other high-resolution schemes. The proposed scheme resolves the fine-scale structure with a higher resolution. Further, it is computationally efficient, produces less spurious oscillations, and shows better conservation of kinetic energy for 3D Taylor-Green vortex case.
  Keywords: Alternative WENO scheme; Hyperbolic equations; Unsteady; Numericalrnfluxes; High-resolution scheme; Compressible flow.
  
  
• Numerical study of combustion and nitrogen oxide generation for recycled flue gas distribution in supercritical carbon dioxide coal-fired boiler with double furnace  
  by Yong Wu, Jinyan Yuan, Mingming Wang, Jimin Wang, Lixin Han, Mingyan Gu, Xiangyong Huang, Huaqiang Chu 
  Abstract: After flue gas recirculation and structural adjustment are adopted to avoid local overheating of the cooling wall, the coal combustion characteristics in the furnace would need to be reevaluated to control nitrogen oxide generation. According to the configuration design of a 1000 MW supercritical carbon dioxide coal-fired boiler with a novel double furnace, a comprehensive model with the Euler-Lagrange framework was used to examine the velocity, the temperature, and the species concentration in the double furnace under the unique heat transfer boundary. The comparative study of the coal combustion and nitrogen oxide generation characteristics on different recycled flue gas distribution ratios was in detail explored. The results indicated that the gas temperature at the exit gradually increases as the recycled flue gas distribution ratio, while the nitrogen oxide concentration gradually increases. When the recycled flue gas rate from different positions is relatively the same, the combustion effect is the best.
  Keywords: supercritical carbon dioxide coal-fired boiler; double furnace; recycled flue gas distribution ratio; combustion characteristics; nitrogen oxide generation; numerical simulation.
  
  
• Numerical comparison of laminar flow and turbulence models of hemodynamics based on pulmonary artery stenosis  
  by Fan He, Xinyu Wang, Lu Hua, Tingting Guo 
  Abstract: Pulmonary artery stenosis is closely related to hemodynamics. In this paper, the laminar and turbulent flows in the same three-dimensional model of pulmonary artery stenosis are numerically calculated by using fluid-structure interaction, and the obtained maximum velocity, pressure and wall shear stress are compared and analyzed. The numerical results show that the hemodynamic parameters of laminar flow model are slightly higher than those of k-? turbulence model. Specially, the wall shear stress at both ends of stenosis is more sensitive to laminar flow model. This study provides the effects of laminar flow and k-? turbulence on pulmonary artery hemodynamics. It gives a basis for the follow-up realistic hemodynamic numerical simulation of pulmonary artery model and has a guiding significance for clinical diagnosis and treatment, and promotes the development of the combination of mechanics and medicine.
  Keywords: Pulmonary artery; stenosis; hemodynamics; laminar flow; turbulence.
  
  
• Pre- and Post-Stall Characteristics of a Very Light Aircraft’s Wing for Different Design Parameters  
  by Berkan An?l?r, Kurtulus Dilek Funda 
  Abstract: The impact of taper ratio, dihedral angle and wing tip shape on the aerodynamics of a very light aircraft’s wing has been investigated by performing URANS simulations at Reynolds number of 5
  Keywords: very light aircraft; VLA; unsteady flow; computational fluid dynamics; taper ratio; dihedral angle; stall cell; wing aerodynamics; SD7062.
  DOI: 10.1504/PCFD.2022.10050230
   
  
• Numerical Investigation of SD7062 Airfoil with SingleSlotted Flap for Different Flight Conditions  
  by Berkan An?l?r, Kurtulus Dilek Funda 
  Abstract: The two-dimensional numerical simulations using unsteady Reynolds-averaged Navier-Stokes are performed to investigate the aerodynamic performance of SD7062 airfoil with a 0.30c single-slotted flap at cruise, takeoff, and landing conditions for various angles of attack corresponding to pre-and post-stall regimes. The time-averaged aerodynamic characteristics of the configurations are compared to the different angles of attack results and other configurations. The maximum lift coefficient value of 3.302 is obtained with 35
  Keywords: single-slotted flap; SD7062; computational fluid dynamics; CFD; flap gap size.
  DOI: 10.1504/PCFD.2022.10050486
   
  
• Variational Formulation of Incompressible Navier-Stokes Equations in Primitive Variables  
  by Akin Ecer 
  Abstract: A "Variational Formulation of Navier-Stokes Equations" are provided on terms of primitive variables. The difference and relationship between the "Mechanical Pressure" and the "Thermodynamic Pressure" is noted. The formulation of the functional requires the distinction between these two variables. The condition of incompressibility also appears in the formulation. The existence of a variational functional suggests the uniqueness of he equations for incompressible flows.rnPrevious formulations require additional variables and an adjoint operator for the formulation of a variational functional. Existence of the present functional suggests that if the pressure is properly defined, the relationship between the compressible and incompressible flows are defined and related to the condition of incompressibility.
  Keywords: Variational Formulation; Incompressible Flows; Navier-Stokes Equations.
  
  
• Investigation of the flow topology evolution between two tandem cylinders using a discontinuous Galerkin method  
  by Xiangjun Shan, Fangjin Sun 
  Abstract: A high-order discontinuous Galerkin method is used to study the transient behavior of the flow between two cylinders in a tandem arrangement. A low Reynolds number of 200 and a pitch ratio of 3.7 are particularly employed, where a gradual transition process of the flow from reattachment flow to coshedding flow is observed. The evolution of the flow topology in the gap between two cylinders, the transient surface pressure and the phase lag of the lift signal from reattachment flow to coshedding flow are investigated, and the physical mechanism responsible for the flow transition is also discussed. The results show that the rolling up of the separated shear layer between two cylinders is closely related to the development of the gap flow. The gap flow is a unidirectional flow in the reattachment regime and gradually develops into a horseshoe-shaped bidirectional flow when the flow transitions to the coshedding regime.
  Keywords: discontinuous Galerkin method; higher-order accuracy; tandem cylinders; low Reynolds number; transient characteristics; incompressible flow.
  
  
• Flow separation control in a two-airfoil system by trailing edge modification and active flow control  
  by Deepak Kumar Singh, Dilip Lalchand Parmar, Arjun Sharma 
  Abstract: Numerical simulations of flow past a NACA0012 airfoil with a slotted flap are conducted using steady Reynolds-averaged Navier Stokes equations at Reynolds number of 5
  Keywords: high-lift system; boundary layer separation; active flow control.
  DOI: 10.1504/PCFD.2022.10052371
   
  
• Eliminating the residual velocity divergence of spectral methods in channel turbulence  
  by Zehao Chen, Le Fang 
  Abstract: The problem of residual velocity divergence exists in numerical simulations of channel flows which use spectral methods. The present contribution analyzes the source of the residual velocity divergence, and introduce a new correction method by adding a new pressure correction substep and using ghost grids. The new method can completely eliminate the residual velocity divergence without breaking the non-slip condition. Numerical results show that the residual velocity divergence is well eliminated, while a-posteriori results are not becoming worse. We then conclude that the numerical simulations by using the present method are more close to the incompressible N-S equations, but the influence to a-posteriori statistical quantities is still worth to be investigated in the future.
  Keywords: channel turbulence; Chebyshev discretization; spectral method; residual velocity divergence.
  
  
• Study of the separation characteristics of gas-liquid-solid multiphase flow in the impeller of a helical axial flow oil-gas pump  
  by Haozhi Nan, Rennian Li, Weiwei Zhou 
  Abstract: During oil and gas transportation, due to transport mixed media, phase separation is easy to occur, which reduces the efficiency of the multiphase pump and may cause "gas blockage" in serious cases. In this paper, the self-designed single stage helical axial flow compression unit was used as the research object to explore the separation characteristics of the fluid medium in the impeller of the pump. Based on computational fluid dynamic(CFD), the Euler multiphase fluid model and the SST k-? turbulence model were used to calculate the flow in impeller. By setting monitoring points in the flow channel, the force movement of bubbles and solid particles is analyzed. The results show that the radial velocities of bubbles and solid particles suddenly change in the middle of the channel. By analyzing the pressure on the impeller surface, the coincidence area and non coincidence area are defined. The results show that in the overlapping area when ?>0.5, GVF is basically consistent with the inlet, and the maximum GVF is 0.8; In the non-overlapping area, when ?>0.5, the maximum GVF is 1, indicating complete gas-liquid separation.
  Keywords: helical axial flow oil-gas multiphase pump; multiphase flow; separation characteristics.
  
  
• The Dynamics of Supersonic Flow Past a New Cusped Leading Edge Airfoil  
  by Saif Akram, Nadeem Hasan 
  Abstract: A new family of cusped leading edge airfoil with great implications in supersonic aircraft design has been proposed in this work. Numerical investigation of unsteady, viscous and laminar compressible flow past the new cusped leading edge airfoil and a conventional biconvex airfoil with the same maximum thickness is carried out and a systematic comparison of the aerodynamic parameters are reported. The value of Reynolds number is held constant which is 5
  Keywords: cusped leading edge airfoil; CFD; drag reduction; supersonic flow.
  DOI: 10.1504/PCFD.2022.10052925
   
  
• Numerical analysis on prediction and attenuation of low speed cavity noise  
  by Sundaram Soma Sundaram 
  Abstract: Prediction and attenuation of noise generated in the cavity with an overhang has been numerically studied. Simulations are carried out such that two-dimensional, unsteady, turbulent, compressible equations are solved. The geometry considered for the simulations is a deep cavity with an overhang. The dimensions of the cavity and the wind tunnel are obtained from literature. Unsteady pressure data has been collected from the walls of the cavity and Discrete Fourier Transform (DFT) analyses of these data have been carried out. The predicted frequencies are found to match with the experimentally measured values. Proper Orthogonal Decomposition (POD) analyses of the data collected indicate the presence of longitudinal duct mode and vortices in the shear layer. The attenuation studies have been carried out by providing a chamfer in the trailing edge. The results indicate the amplitude of the noise has been reduced by five times for a chamfer of 45
  Keywords: Cavity with overhang; Noise attenuation; Numerical simulation; DFT analysis; POD analysis; hydrodynamic mode; duct mode.
  
  
• Investigation of upper airway changes in orthognathic surgery with computational fluid dynamics analysis  
  by Ilker Inan, Erman Aslan, Frantzeska Karkazi, Yasemin Bahar Acar, Banu Korbahti, Riza Guven 
  Abstract: In this retrospective study, Computational Fluid Dynamics (CFD) simulation was used to observe changes in airway in a patient (20-year-old male) who underwent bimaxillary surgery with maxillary advancement and mandibular setback. Bimaxillary orthognathic surgery is an invasive approach that is used for the correction of skeletal Class III malocclusion related with dental surgery. In order to perform CFD analysis, at the first stage Cone-Beam Computed Tomography (CBCT) data from preoperative (2 months before surgery) and postoperative (6 months after surgery) were used to build the numerical domain at three different volumetric flow rates of 30 L/min, 15 L/min and 7 5 L/min. In addition to volume changes in the airway, pressure drop, shear stress, streamlines were analysed for inhalation and exhalation phases at different volumetric flow rates. The total upper airway volume after the operation narrowed by 13 69% compared to the pre-operation.
  Keywords: finite volume method; FVM; turbulent flow; upper airway change; upper airway flow.
  DOI: 10.1504/PCFD.2023.10054095
   
  
• Performance of different wall functions in turbulent flow inside a pipe, a diffuser, and behind a backward-facing step  
  by Mahdi Mohseni, Ali Amini 
  Abstract: Traditionally, there are two approaches to modeling the turbulent flow near the wall. In one approach, near-wall flow properties are calculated using semi-empirical relationships called wall functions instead of solving equations. In this method, the time and cost of calculations will be relatively low. In the second approach which is termed “low Reynolds number models”, the equations are solved up to the wall, and as a result, the calculation cost is much higher. The advantages of wall functions have led to their widespread use in the simulation of turbulent flows, as well as their development even in recent years. So, in this research, the performance of different wall functions and near wall treatments is investigated numerically. For this purpose, based on the available experimental data, turbulent flow inside a straight tube, a backward-facing step and a diffuser have been selected as examples of simple, complex and widely used flows. The near wall treatments used are divided into two categories with fine mesh and coarse mesh.
  Keywords: wall function; near-wall treatments; turbulent flow; pipe; step; diffuser; numerical solution.
  DOI: 10.1504/PCFD.2023.10054194
   
  
• The effect of building layout patterns on the formation of heat islands: a computational study  
  by Veena K, Parammasivam K M, Venkatesh T N 
  Abstract: Numerical methods are getting high acceptance worldwide for studying heat islands. As most of the existing studies have not investigated the importance of spacing between buildings, the main goal of the current study is to compare the behaviour of wind patterns and heat island formation in building clusters with less spacing and adequate spacing according to National Building Codes of India (NBC)2016. Six building layouts with a combination of high-rise and low-rise buildings are numerically studied using buoyant- Boussinesq solvers. Results show that the near-surface air temperature is higher for less spacing cases than adequate spacing cases. An air temperature higher than the threshold value (?T = 0.7K) was identified at 55% of the area near the ground for less spacing subcase. In comparison with less spacing cases, the wind velocity near the building cluster was increased by 17.7%, and the temperature spread decreased by 35.04% by following the NBC.
  Keywords: Urban Heat Island; National Building Codes; Computational Fluid Dynamics; near-surface air temperature; thermal comfort; wind environment; temperature distribution.
  DOI: 10.1504/PCFD.2023.10059257
   
  
• Numerical study of liquid imbibition and contact line pinning in a sealing gap for corrosion protection of metal housings  
  by Daniel Hagg, Eifert Alexander, Torsten Troßmann, Bettina Frohnapfel, Holger Marschall, Martin Woerner 
  Abstract: Sealing gaps are common in housings that protect sensitive assemblies from potential damage by the environment. A prevalent measure to prevent water from reaching the sealing ring are pinning grooves. In this work, the influence of material wettability on the capillary-driven penetration of water into a generalised sealing gap geometry with pinning groove is investigated numerically for the first time. Interface-resolving two-phase flow simulations are performed with a diffuse-interface phase-field method solving the coupled Cahn-Hilliard Navier-Stokes equations. In the simulations of a gap geometry with pinning groove, the imbibition process is slowed down but not stopped for contact angles up to about 50? , while imbibition is prevented for contact angles larger than about 55? . The different behaviour is explained by the edge effect in wetting which interacts with liquid inertia. Volume-of-fluid simulations performed for comparison show similar behaviour with slight differences in imbibition speed and much higher spurious currents.
  Keywords: Cahn-Hilliard; capillarity; diffuse interface; edge effect in wetting; electronic housing; imbibition; phase-field method; sealing gap.
  DOI: 10.1504/PCFD.2023.10055191
   
  
• INVESTIGATION OF KINETICS OF THIN LAYER DRYING OF FRUITS USING COMPUTATIONAL FLUID DYNAMICS  
  by Chukwunonso Nwoye, Chukwunenye Okoronkwo, Godswill Nwaji, Obiora Ezenwa 
  Abstract: The roles of temperature and velocity of air and the limits of their influence in thin layer drying of fruits were studied using computational fluid dynamics code- ANSYS FLUENT 18. Unripe banana (Musa cavendishii) was used as sample and mass transport from the fruit to the drying air was simulated by solving specie transport equation without reaction. Velocity helped to regulate the concentration gradient between the chamber space and the fruits surface as it was responsible for the transportation of free molecules at the surface of the fruit to the environment. Temperature on the other hand was the major determinant of the rate at which species were transported from the fruit to the drying air and it is defined by mass diffusivity. The computed values of effective diffusivity at the test temperatures ranged between 1.62E-10 - 3.85E-10. However these values dropped slightly when shrinkage effect was factored in.
  Keywords: Drying; Fruits; CFD; Porous media; Shrinkage.
  
  
• Fin effectivity investigation at solid-liquid phase change in axisymmetric heat exchangers using lattice Boltzmann method  
  by Zeinab Hajamini, Hamed Moqtaderi, Sajedeh Kebriti 
  Abstract: The purpose of this article is to analyze the fin parameters in a heat exchanger to optimize the melt rate of PCM. Shell and tube heat exchangers are considered. The shell contains PCM and annular fins placed on the tube wall. The fluid flow, heat transfer, and melting equations were solved using a 2D axisymmetric Lattice Boltzmann Method (LBM). LBM enthalpy-based method was developed in an axisymmetric form. According to our study of the effect of fin number and length on PCM melting rate, the optimal number of fins for thicknesses of 2R/20 , 2R/40 and 2R/200 is 3, 2, and 2, respectively, while the optimal length of fins for these thicknesses is 0.8R. Moreover, we also introduced a 3-fin arrangement with uneven fin length, which increased melting rate. The effect of the secondary fin on the melting rate of PCM was also studied.
  Keywords: Fin effectivity; Solid-liquid phase change; Lattice Boltzmann method; Axisymmetric heat exchanger.
  
  
• Numerical Analysis of Superoleophilic-Superhydrophobic Filtration System for Emulsions Separation Using Lattice Boltzmann Method  
  by Luma Al-tamimi, Hassan Farhat 
  Abstract: A novel 3D hybrid quasi-steady thermal lattice is used to study the oil-water separation in stable emulsions and evaluate the efficiency of superoleophilic/superhydrophobic filtration systems through a variety of parameters. This work introduces the first 3D LBM model that combines the effects of surfactant and thermal conditions on the contact angle of a droplet adhering to a wall while accounting for all factors contributing to the complexity of emulsions systems. The LBM model demonstrated several key advantages: it mimics the superwetting filter system with any desired contact angle, evaluates wetting and oil-water separation under a broad array of conditions and increases the opportunity for innovation of superwetting filter designs by allowing modification and validation of various conditions. Furthermore, it is useful for highlighting the mechanisms that take place in the filtration process, such as the suspended phase behaviour, coalescence, and breakup, and determine which parameters can influence the greatest efficiencies.
  Keywords: lattice Boltzmann method; LBM; Gunstensen model; contact angle; thermal model; surfactants; high viscosity ratio; super-wetting material filter.
  DOI: 10.1504/PCFD.2023.10056045
   
  
• Numerical investigation of the effect of swirl number on performance, combustion, and emissions characteristics in a converted heavy-duty natural gas engine  
  by Fatih Aktas 
  Abstract: In this research, the performance, combustion characteristics, and emission behaviour of a diesel engine converted to a spark ignition engine running on natural gas were investigated. The studies were performed at full load, 2,300 rpm, constant spark ignition time, and seven different swirl ratios. As a result, the homogeneous-air fuel mixture formed in the cylinder due to the swirl ratio rising, and the increased combustion performance dominated the heat loss because of the rise in the swirl number, thereby improving the performance. However, with the increase of in-cylinder temperatures, NOX emissions increased. As the swirl ratio increased from 1.2 to 2.4, the gross indicated power (GIP), indicated mean effective pressure (IMEP), indicated thermal efficiency (ITE), and maximum pressure rise rate (MPRR) values increased by 4.1, 4.13, 3.98, 102.2%, while the gross indicated specific fuel consumption (GISFC) value improved by 3.97%.
  Keywords: natural gas; heat transfer; spark ignition; diesel engine; converted engine; emissions; G-equation; swirl number; combustion; internal combustion engine.
  DOI: 10.1504/PCFD.2023.10056598
   
  
• Investigations on the use of URANS equations to characterize the wind turbine wake in a non-neutral boundary layer  
  by Siheme Guezmir, Amina Mataoui, Ouahiba Guerri 
  Abstract: The aim of this paper is to show to what extent unsteady Reynolds averaged Navier-Stokes (URANS) equations, coupled to the actuator disk (AD) theory, could simulate the flow in the wake of wind turbines, taking into account atmospheric boundary layer (ABL) thermal stratification. First, the URANS/AD model is validated by the computation of the flow in the wake of a porous disk modeling a small wind turbine. Then, the investigations are applied to a large wind turbine in a neutral and non-neutral ABL. The obtained velocity contours and profiles are compared to available LES results. The effects of the thermal stratification on the added turbulence and expected turbine power are evaluated. The results obtained show the ability of URANS/AD calculations to characterize wind turbine wakes in a non-neutral ABL.
  Keywords: wind turbine wake; non-neutral boundary layer; ABL; CFD; URANS.
  
  
• Three-dimensional Flow Evaluation of Monarch Butterfly Wing  
  by Fadile Yudum Comez, Nevsan Sengil, Kurtulus Dilek Funda 
  Abstract: The current study aims to examine the flow field around a Monarch butterfly wing at different angles of attack. A fully opened forewing configuration for the Monarch butterfly wing has been selected for analysis at a maximum chord length. To mimic the membrane of the real Monarch butterfly wing, the thickness of the wings has been taken as 0.15 mm. In this study, the Reynolds number is calculated as 9,724 for a 5 m/s freestream velocity. The effect of the angle of attack has been investigated between [0, 40
  Keywords: CFD; Monarch Butterfly; Micro Air Vehicles; leading-edge vortex; unsteady aerodynamics.
  DOI: 10.1504/PCFD.2023.10058561
   
  
• RANS simulation of wind pressure development on mono-slope canopy roofs  
  by Ajay Pratap, Neelam Rani 
  Abstract: This study examines the effect of various roof slopes of mono-slope canopy roofs (MCRs) on wind pressure distribution under various wind directions. The wind tunnel experiment is carried out on a 15
  Keywords: mono-slope canopy roof; computational fluid dynamics; CFD; pressure coefficient; Reynolds-averaged Navier-Stokes; RANS; overall coefficient; drag and lift coefficient.
  DOI: 10.1504/PCFD.2023.10058679
   
  
• Unsteady three-dimensional multiphase modeling of anode flow distributor in PEM electrolysis cell  
  by Safiye Nur Ozdemir, Imdat Taymaz 
  Abstract: A polymer electrolyte membrane electrolysis cell (PEMEC) is a system in which water is oxidised at an oxygen electrode, producing oxygen gas on the anode electrode and hydrogen gas on the cathode electrode, respectively. In this study, we aim to develop a three-dimensional, unsteady numerical model of the anode flow field plate (AFFP) for the PEMEC system that focuses on two main objectives: the first objective is to characterise the two-phase flow distribution. The second purpose is to change the channels in the AFFP, analyse their effect on pressure drop, velocity, and oxygen gas distribution, and determine the appropriate number of channels. The three-dimensional, single-domain, and isothermal model of an AFFP was applied in the commercial computational fluid dynamics (CFD) code; it was well-validated with the experimental results of a PEMEC with a parallel flow field. Numerical results show that the pressure gradient decreases diagonally from the inlet port to the outlet port along with the AFFP. It was recorded that when the number of electrode channels was increased from 4 to 16, the pressure drop decreased by 33% but also increased by approximately 73 Pa when it was increased from 16 to 20.
  Keywords: green hydrogen production; PEM electrolysis cell; anode flow field plate; AFFP; computational fluid dynamics; CFD modelling; two-phase flow.
  DOI: 10.1504/PCFD.2023.10058697
   
  
• Flow separation control in a three-element airfoil system at moderate Reynolds number  
  by Deepak Kumar Singh, Dilip Lalchand Parmar, Arjun Sharma 
  Abstract: The flow past a three-element, high-lift system is studied using Reynolds- Averaged Navier Stokes simulations at Reynolds number of 1.5
  Keywords: high-lift system; boundary layer separation; active flow control.
  DOI: 10.1504/PCFD.2023.10058988