computational fluid dynamic (cfd)

Natural gas processing is a crucial industrial operation that transforms raw gas into a valuable product by removing impurities such as water, acidic gases, and heavy hydrocarbons. While thermodynamics and chemical kinetics have traditionally been emphasized in gas processing discussions, solid particle technology, which involves the behavior and application of particulate materials, plays an increasingly essential role in ensuring the efficiency, safety, and sustainability of these operations. This technology is fundamentally involved in various stages of natural gas processing by examining the presence of solid particles (such as dust, hydrates, and combustion-derived suspended particles) in the gas stream.Natural gas contains solid particles that, if not addressed in upstream operations, can damage equipment and create transport issues. This technology ensures the safe and efficient use of natural gas by removing solid particles before they enter the pipeline. Effective separation of these solids is essential to prevent equipment wear, pipeline blockages, and damage to downstream catalytic systems. To achieve this, devices such as cyclonic separators, scrubbers, and filtration units—based on the principles of fluid particle dynamics—are commonly used. The design of these devices requires a deep understanding of particle size distribution, inertia, and drag forces in multiphase flow environments.On the other hand, hydrate formation, which includes semi-solid compounds that form in natural gas pipelines at low temperatures and high pressures, can lead to blockages. In this regard, adsorption processes using porous solid particles to remove water and other impurities contributing to hydrate formation help prevent blockages. In dehydration processes (using molecular sieves) and acid gas removal, for example, activated alumina or amine-functionalized solids—fundamentally based on porous adsorbent particles—are used. The performance of these processes is closely related to the properties of the solid adsorbents, including particle size, porosity, surface area, and mechanical strength. Therefore, advances in solid particle engineering, such as optimizing granulation techniques or developing hierarchical-structured adsorbent particles, are crucial for improving process reliability and performance.In addition to separation and adsorption, particle technology plays an essential role in the design and operation of gas/solid reactors, used in sulfur recovery (e.g., Claus process off-gas treatment) and carbon capture applications. Fluidized bed reactors, often used in these processes, require precise control of particle flow behavior under varying pressures, temperatures, and chemical environments. Emerging computational tools, such as Computational Fluid Dynamics (CFD) integrated with Discrete Element Modeling (DEM), enable the simulation of complex particle-laden flows, providing powerful platforms for reactor design optimization and troubleshooting operational issues.As the natural gas industry moves toward lower-carbon and more sustainable operations, solid particle technology plays a broader role. For instance, solid adsorbents for CO₂ capture from natural gas streams are under development. The production of these adsorbents requires precise control over particle synthesis, morphology, and surface functionalization. Similarly, managing the emission of contaminated solid particles, such as mercury-laden solids or waste adsorbents, requires advanced particle characterization techniques (e.g., laser diffraction and dynamic image processing) and innovative waste treatment strategies.Thus, solid particle technology must act as a critical factor for the efficient, safe, and sustainable processing of natural gas. This technology supports key operations, from solid-liquid-gas separation to adsorption and chemical conversion. The integration of advanced particle characterization methods, process modeling, and the synthesis of new particulate materials for resilience and environmental compatibility is essential. Ongoing interdisciplinary research that bridges materials science and chemical engineering will be pivotal in achieving transformative advancements in natural gas processing operations.

Industrial waste incinerators in gas refineries or sulfur recovery units are responsible for eliminating the waste gases such as hydrogen sulfide (H2S) and carbon dioxide (CO2) produced in the process. Most of these units are facing problems such as incomplete combustion, lack of proper control systems for measurement, and the presence of pollutants such as carbon monoxide and nitrogen oxides, etc. Therefore, in this research, to improve the performance of the waste incinerator of Fajr Jam Refinery, furnace modeling was done by computational fluid dynamics (CFD). The software Fluent 6.3 is used for the modeling of the incinerator. To achieve this goal, parameters such as the ratio of fuel to air in the inlet duct of main air, the amount and role of the additional air inlet at the bottom of the chimney, the installation of the additional air inlet duct at the end of the furnace for mixing more oxygen and H2S, air injection into the inlet duct of acid gas and the feasibility of preheating the incoming air and its effect on the combustion efficiency was investigated. The modeling results showed that increasing the airflow can reduce the amount of CO and H2S, but the amount of NOx compounds increases. To establish a balance between the output of pollutants from the furnace, solutions to improve the unit performance were presented, and the appropriate flow range of excess air in the furnace was determined.
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One of the powerful tools for fire investigation is Computational Fluid Dynamics, which has the capability to predict all influential parameters in fire, such as temperature, velocity, pressure, toxic species, and radiation. However, this method requires validation to assess the accuracy of the results. This can be achieved by simulating and comparing the results with experimental data to evaluate the numerical accuracy and examine the validity of the governing models used in the simulation. In this study, the temperature conditions, velocity, and combustion species were investigated and analyzed in the geometry of the fire compartment, by comparing the results of two software, FDS and OpenFOAM. It was observed that both software have similar validation results, although OpenFOAM performs slightly better than FDS. For instance, the temperature and CO2 species results in OpenFOAM have a relative error of 22.4 and 16%, while FDS have a relative error of 24 and 31%.

In the present paper, numerical simulations of laminar forced convection flow and entropy generation analysis in a 2-D duct with two sudden expansions are investigated. These two expansions are created by four inclined backward facing steps and beget the separation flows and vortex regions. The vortex regions have the significant effects on the heat transfer rates and flow irreversibility. The inclination angle of steps is one of effective parameters on the control of the separation flows, heat transfer rates and flow irreversibility. In this paper, after calculation of velocity fields and temperature distributions, the effect of the step inclination angle on the separated flows, Nusselt number, friction coefficient, entropy generation number and Bejan number is studied. To obtain the temperature distributions and velocity fields, the set of governing equations including mass, momentum and energy equations are solved by the finite volume methods and computational fluid dynamic (CFD) techniques. For simulating the inclined surfaces of steps in Cartesian coordinates, the blocked-off method is used. Also, thermodynamic second law analysis is employed to calculate the entropy generation and flow irreversibility. Finally, the effect of the Brickman number on the entropy generation number and Bijan number is investigated graphically.

In this study, the effects of linear and rotational speed of the friction stir welding tool was investigated on the heat generation and distribution at surface and inside of workpiece, material flow and geometry of the welding area of poly methyl methacrylate (PMMA) workpiece. The commercial CFD Fluent 6.4 software was used to simulation of the process with computational fluid dynamic technique. To increase the accuracy of simulation, weld area was modeled as a non-Newtonian fluid with pseudo melt behavior around tool pin. The results of the simulation showed at the higher the proportion of rotational speed to linear speed, the material flow in front of the tool and the welding region became bigger. The maximum temperature and turbulence generated heat and material flow were observed at the advancing side. The simulation results were showed acceptable agreement with experimental results. Based on the studied parameters, the maximum generated heat was of 115° C, the maximum material velocity was 0.24 m/s around tool shoulder and maximum pressure on the workpiece was predicted 9 MPa.

Precise modeling has great importance in systems which are designed to work in transonic regions. The scope of current investigation includes numerical simulation of static aeroelastic phenomena of deformable structures in transonic regimes. Transonic flow brings lots of instabilities for aerodynamic systems. These instabilities bring nonlinearity in flow and structure solvers. Due to improvements in numerical methods and also enhancement in computing technologies, computational costs reduced and high-fidelity simulations are more applicable. Simulations in this paper are done in transonic flow (M = 0.96) on the benchmark wing AGARD 445.6. The procedure includes modal analysis, steady flow simulation and investigation of structure’s elastic behavior. At the first phase, the geometry model is validated by modal analysis with regards to comparison of first four natural frequencies and corresponding mode shapes. Then, a loose or staggered coupling is used to analyze aeroelastic behavior of the wing. In each simulation step, imposed pressure on the surfaces of the wing caused by transonic flow regime, deforms the structure. In the results section, a comparison between imposed pressure coefficients in each step with the existing literature and experimental results are reported. Also, pressure coefficients in each steps are calculated and reported. In this investigation by using multiple steps in one-way fluid-structure analysis, deformations are reduced in each step and as a result, the structure reached its static stability point.

In recent years, environmental concerns are the greatest challenge in vehicle design. Electric vehicles seem to be a suitable solution to this problem. Therefore, numerous measures have been taken to increase the efficiency, reduce losses, and improve the performance of these vehicles. Aerodynamic characteristics improvement is a key issue that should be considered in vehicle design. In this paper, the effects of improving the aerodynamic characteristics on the electric vehicles are analyzed. For this purpose, installing movable rear spoiler along with a controller and covering the rear wheels have been proposed. In order to evaluate the proposed solutions, their effects on an electric vehicle prototype that has been constructed and developed by the authors have been modeled in MATLAB SIMULINK environment. The flow around the electric vehicle has been studied in ANSYS in order to calculate the drag and lift coefficients. The flow has been numerically solved using the Computational Fluid Dynamics (CFD). The standard k-ε turbulence model has been utilized in this study. The results show that improvement of aerodynamic characteristics in electric vehicles not only increases the stability of the vehicle, but also has a significant impact on the energy storage system, mileage, and the electric motor efficiency.

The unsteady rotating force or dipole strength distribution, acting by the fan or propeller on the fluid, is predicted by inverse method. In this method, the far-field acoustic pressures are used in non-cavitating condition. In this paper, the far-field acoustic pressures are obtained from Ffowcs Williams and Hawkings (FW-H) equations using computational fluid dynamic (CFD) in specific hydrophone array and then the unsteady rotating force, acting by the propeller on the fluid, is obtained as the most important sound source in non-cavitating condition. The unsteady rotating forces are extracted using inverse method by analytical code in MATLAB. The correct solution is independence to the optimum select of regularization parameter from transfer function; the transfer function represents relationship between the force coefficients and the far-field acoustic pressure. Therefore, the appropriate range of regularization parameter should be choice in order to an ill-conditioned problem from transfer function is solve. The analytical code is solved for different regularization parameters and then the unsteady rotating forces are obtained for three sections on the blade surface. The inverse method could be used for dipole strength distribution calculation as the most important sound source in non-cavitating condition in order to design the noiseless of marine propeller.