Numerical Simulation Of Process Research Articles

Numerical investigation of the sensible heat storage in novel electrostatic precipitators with liquid-filled collection electrodes

Heat recovery from flue gas holds significant potential for energy conservation. A strategy is proposed for recovering and storing heat in electrostatic precipitators by utilizing liquid-filled collection electrodes. In the prototype, the hollow collection electrode is connected to the heat storage tank. Convective heat transfer occurs between the gas stream and the liquid contained in the collection electrode. The heat storage mechanism is revealed by numerical simulation of corona discharge, flow and heat transfer processes in a simplified electrostatic precipitator. The results indicate that both the gas-side and liquid-side heat transfer coefficients reach steady values within approximately 100 s. The buoyancy-driven liquid flow results in a heat transfer coefficient that is 28 times higher than that for gas-side forced convection. Increasing the gas inlet temperature leads to a greater buoyancy force and, consequently, a higher heat transfer coefficient on the liquid side. Both ionic wind and inlet velocity affect the gas-side heat transfer. The ionic wind disturbs the thermal boundary layer, leading to a 27.9 % increase in the gas-side heat transfer coefficient at an inlet velocity of 0.5 m/s. Furthermore, this enhancement becomes more pronounced as the inlet velocity decreases. The flow pattern of liquid in the collection electrode and heat storage tank is crucial to the heat storage process. Additionally, installing the heat storage tank above the electrostatic precipitator provides added benefits. During the process of heat storage, the largest heat resistance is found on the gas side.

Numerical Simulation as a Tool for the Study, Development, and Optimization of Rolling Processes: A Review

Rolling is one of the most important processes in the metallurgical industry due to its versatility. Despite its inherent advantages, design and manufacturing by rolling still rely on trial-and-error-based optimizations, which reduces its efficiency. To minimize the cost and time spent on the development of new rolling schedules, various analytical and numerical methods have been used in recent years. Among other alternatives, simulations based on the finite element method (FEM) are the most widely used. This allows for the analysis of the feasibility of new rolling schedules considering metal alloys with different characteristics, process conditions, or the creation of new operations, as well as the optimization of existing ones. This paper presents a literature review including the latest developments in the field of numerical simulation of rolling processes, which have been classified according to the type of rolling into the following categories: flat rolling, shape rolling, ring rolling, cross-wedge rolling, skew rolling, and tube piercing.

Foreign object damage characteristics of a thin nickel-based superalloy plate at room and high temperatures

Turbine blades with thin-walled structures usually works in harsh environments, and foreign object damage (FOD) is one of the conditions of special concern. In this paper, the FOD characteristics of thin nickel-based superalloy plates are studied by a combination of experimental, numerical and analytical methods, considering room and high temperatures, different impact conditions and plate thicknesses. An easy-to-use test system is developed to realize high speed impact of the thin nickel-based superalloy plate under elevated temperature. Crater morphologies, internal microstructure, and residual stress are analyzed after impact with different conditions. Numerical simulation of the impact process is performed by using Johnson-Cook (J-C) constitutive model. Based on Hertz theory, an analytical method for calculating the crater length and depth is proposed considering the deformation of the impact steel sphere. Results shows that the FOD characteristics at high temperature is significantly different from that at room temperature. The crater has lager dimensions under high speed and elevated temperature. Moreover, significant grain refinement is obvious and the dislocation layer is also thicker at higher speed and higher temperature. Due to the effect of high temperature softening, hardness and residual stress after impact with elevated temperature is lower than that at room temperature. Besides, non-normal impact mainly influences Goss texture and distribution of residual stress after high temperature impact. In addition, it is found that thickness have a significant effect on the FOD characteristics especially when the plate is thinner. The validity of the numerical model and analytical method is proved by comparing with the experimental results. The present study can provide data foundation and numerical analysis support for the damage assessment and maintenance of turbine blades.

Numerical Modelling and Simulation of the Shear-Slitting Process of Electrical Steels

Numerical Modelling and Simulation of the Shear-Slitting Process of Electrical Steels

Numerical Simulation and Improvement of TSL Smelting Process: the Effect of Lance Bending

Numerical Simulation and Improvement of TSL Smelting Process: the Effect of Lance Bending

Multiphase Numerical CFD Simulation of the Hydrothermal Liquefaction Process (HTL) of Sewage Sludge in a Tubular Reactor

This article presents multiphase numerical computational fluid dynamics (CFD) for simulating hydrothermal liquefaction of sewage sludge in a continuous plug-flow reactor. The discrete particle method (DPM) was used to analyze the solid particles’ interaction in liquid–solid high shear flows to investigate coupling computational fluid dynamics (CFD). Increasing solid particles’ interactions were observed with the increasing liquid velocity. The study examined the influence of parameters such as flow rate, temperature, and residence time on the efficiency of bio-oil production. An increase in temperature from 500 to 800 K caused an increase in the amount of biocrude oil produced from 12.4 to 32.9% within 60 min. In turn, an increase in the flow rate of the suspension from 10 to 60 mL/min caused a decrease in the amount of biocrude oil produced from 38.9 to 12.9%. This study offers insights into optimizing the flow channel of tubular reactors to enhance the HTL conversion efficiency of sewage sludge into biocrude oil. A parametric study was performed to investigate the effect of the slurry flow rate, temperature, and the external heat transfer coefficient on the biocrude oil production performance. The simulation data will be used in the future to design and scale up a large-scale HTL reactor.

Numerical Simulation of Solidification Process in an SCR Wheel and Belt Continuous Caster

Numerical Simulation of Solidification Process in an SCR Wheel and Belt Continuous Caster

Numerical simulation and optimization of Pervaporation process based on Heat-Mass-Flow coupling

Pervaporation (PV) has the advantages of low energy consumption and high separation efficiency, but the trade-off effect between flux and separation factor restricts its large-scale application. Based on the conservation equations of mass, momentum and heat, a transient model of the whole PV process coupled with heat-mass-flow was established in this paper. The effects of feed temperature, feed concentration and feed flow rate on heat and mass transfer in PV process were analyzed. TEOS crosslinked PDMS/PTFE-PVDF membrane was prepared by scraping coating method. The reliability of the model was verified by taking n-butanol/water separation system as an example. The concentration polarization and temperature boundary layer under different operating conditions are discussed. The effect of operating conditions on the separation performance was evaluated by response surface method, and the optimal operating conditions are obtained. The results show that the concentration polarization of the membrane surface becomes more obvious with the increase of feed concentration. The temperature boundary layer decreases with the increase of feed flow rate. Surprisedly, there is a significant temperature gradient in the membrane, and the maximum temperature difference between the two sides of the membrane is as high as 1.02 K. Diffusion in the membrane is the rate controlling factor of PV process. The contribution of operating conditions to the separation performance is in the order of feed temperature > feed concentration > feed flow rate. The best operating conditions are: feed temperature 350.2 K, feed concentration 3.8 wt% n-butanol/water and feed flow rate 23.6 L/h. This work provides a theoretical basis for the design of PV membrane materials and the optimization of PV operating conditions.

Parametric optimisation of laser welding of stainless steel 316L

This paper presents numerical and experimental studies focused on the optimisation of laser welding parameters for AISI 316L stainless steel. The focus of the numerical studies was to obtain the mathematical model with the least time complexity and the highest fidelity. Based on the comparison of different mathematical models, a combination of two models, double ellipsoidal and conical models, was found to be optimal for the numerical simulation of the laser welding process. The studies were also complemented by material characterization studies for validation purpose. A pulse duration of 8 milliseconds and a current of 400 amperes with an average power of 380W were found to be the optimum parameters for laser welding of standard gauge 12 sheet of stainless steel AISI 316L. In addition, the effect of duty factor of the pulsed laser beam on the weld profile was also investigated and was found to be a major contributor to the optimisation process. The properties of the sample welded with the optimised set of parameters were also compared with the base metal, and based on the mechanical characterisation studies, it was found that the yield strength and hardness of the welded sample were improved, but the overall ductility was slightly reduced as compared to the base metal. The average weld zone size was also reduced by increasing the power density due to multiple reflections of the beam.

Characterization of non-steady-stage during friction stir welding

Friction stir welding (FSW) has been widely applied in joining lightweight metals such as aluminum alloys. Similar to traditional arc welding, FSW also experiences a non-steady-stage in the initial stage of welding. Regarding the characteristics of the non-steady-stage during the FSW process, there has been a lack of research by scholars in this area. In this work, the Coupled Eulerian-Lagrangian (CEL) method was employed to perform a numerical simulation of the FSW process. Combined with related experiments, it was discovered that the instability of temperature and axial force leads to the characteristic transition from tunnel defects to void defects during the non-steady-stage. Furthermore, the length of the non-steady-stage was found to be 30 mm, and its duration is influenced by the welding conditions. Tensile tests have confirmed that the welding quality of the remaining part, after removing the keyhole at the weld’s end, is reliable.

Numerical simulation of freak wave generation and evolution process based on SPH method

With the occurrence of maritime accidents all over the world, the study of extreme waves has been promoted. These extreme waves are often called freak waves in the scientific community. At present, a variety of mechanisms are proposed to explain freak waves in the marine environment, such as directional focusing, dispersive focusing, and nonlinear modulation instability. At first, a hydrodynamic model is established based on the Smoothed Particle Hydrodynamics (SPH) method in the C# environment, and the regular wave generated by the piston wave generator is numerically simulated. Secondly, the simulation results were analyzed and visualized by using Paraview software, compared with physical experimental datas to verify the reliability of this model. Then, the generation and evolution of freak waves were numerically simulated through the movement of piston wave generators on both sides of a 2D numerical wave flume, and the influence of frequency and amplitude was analyzed by using directional focusing. The results show that if the frequency is smaller and the amplitude is larger, it is more likely to generate freak waves and wave-breaking phenomena. This study lays a foundation for the research of freak waves in the future.

Simulation study on the breakup process of kerosene Gel Jet in transverse airflow

The gel propellant not only inherits the characteristics of liquid propellants, such as high specific impulse, multiple ignition capabilities, and adjustable thrust, but also offers an advantage type of solid propellants, including reduced risk of leakage, long-term storage feasibility, and ease of maintenance. In this study, numerical simulations were conducted to investigate the atomization and mixing process of kerosene gel jets in high-speed crossflows. The study reveals that the jet breakup process primarily involves two forms of breakup: columnar breakup dominated by Rayleigh Taylor’s unstable wave and surface breakup dominated by Kelvin Helmholtz’s unstable wave. These two forms coexist, complement each other, and interact with each other. The numerical simulation of the kerosene gel breakup process provides favorable support for studying its combustion characteristics in the rotating detonation engine.

Numerical simulation of the water landing process of a light civil helicopter in level 5 sea conditions

A helicopter emergency flotation system can provide flotation capability after the helicopter accidentally falls into the water. To solve the problem of attitude change of a helicopter after landing in water, a numerical simulation was carried out on a light civil helicopter with a weight of 3.5 t. It was simulated in level 5 sea conditions, the traveling speed was 15.4 m/s, and the height of the lowest point of the hydrostatic helicopter from the water surface was 250-260 mm, with or without lift, with or without floats. Landing on the water can be done with either basic or elliptical floats and in three different postures. The simulation results show that equipping a helicopter with pontoons can significantly improve its overturning resistance and flotation capabilities, but the impact on a helicopter equipped with pontoons will increase. Landing a helicopter in the water at a certain elevation angle is beneficial to the stability of the helicopter. A helicopter with a basic pontoon is more stable when it lands in the water. The performance is higher than that of the ellipsoidal pontoon, but the pitch stability of the basic pontoon is lower than that of the ellipsoidal pontoon.

Comparison of homogeneous anisotropic hardening models in the case of the direct redrawing of a DP600 steel

The use of DP600, an advanced high strength steel, has gained significant attention in automotive industry, especially for complex structures that require multi-step forming operations, leading to non-linear strain path changes. From a numerical modelling perspective, the use of advanced constitutive equations has enabled a precise representation of a large range of behaviors, encompassing reverse and orthogonal strain path changes. Within this context, this study is dedicated to the numerical simulation of a two-step deep drawing process based on distortional plasticity. Two models developed within the Homogeneous Anisotropic Hardening (HAH) framework are considered. This study presents a comparison of the model predictions, calibrated over the same experimental database, in terms of their ability to predict the strain path changes and mechanical behavior of the material during the forming process. Several outputs like the punch load evolution and the strain field are compared with experimental data.

Numerical simulation of the hydrogen charging process in an adsorption storage tank

Adsorption storage utilizing activated carbon is acknowledged as a promising approach for hydrogen storage duo to its high efficiency. This study compares the activated carbon adsorption storage method with the conventional empty tank storage approach. Finite element simulation is conducted to analyze the hydrogen charging process. Results reveal that under conditions with an initial temperature of 281 K and a storage pressure of 50 MPa, the adsorption tank exhibits a higher system volumetric capacity compared to the empty tank, with an increase of 12.6%. Furthermore, the influence of activated carbon's macroporosity and adsorption performance on storage capacity is investigated. It is indicated that increasing macroporosity effectively enhances storage capacity. Additionally, a comparison between the hydrogen storage performance of AX-21 activated carbon and carbon nanotubes (CNTs) highlights the significant impact of adsorption performance of the adsorbent materials on the storage capacity and temperature distribution.

On the Fundamentals of Reverse Ring Rolling: A Numerical Proof of Concept.

Ring Rolling is a near-net manufacturing process with some measurable dimensional inaccuracies in its products. This fact is exaggerated even more under the scope of high-precision manufacturing, where these imprecisions render such products unfitting for the strict dimensional requirements of high-precision applications (e.g., bearings, casings for turbojets, etc.). In order to remedy some of the dimensional inaccuracies of Ring Rolling, the novel approach of Reverse Ring Rolling is proposed and investigated in the current analysis. The conducted research was based on a numerical simulation of a flat Ring Rolling process, previously presented by the authors. Since the final dimensions of the ring from the authors' previous work diverged from those initially expected, the simulation of a subsequent Reverse Ring Rolling process was performed to reach the target dimensions. The calculated deformational results revealed a great agreement in at least two of the three crucial dimensions. Additionally, the evaluation of the calculated stress, strain, temperature and load results revealed key aspects of the mechanisms that occur during the proposed process. Overall, it was concluded that Reverse Ring Rolling can effectively function as a corrective process, which can increase the dimensional accuracy of a seamless ring product with little additional post-processing and cost.

Finite element simulation of the complete sheet metal blanking cycle: Effect of blanking clearance on force curve and cut edge quality

Sheet metal blanking process is a manufacturing process that is widely used in sheet metal forming and particularly in the electronics and automotive industries. The outcome and quality of the blanked parts are affected by various parameters such as the blanking clearance, the sheet metal mechanical properties and the wear of tools. However, experimental campaigns to assess the effects of these parameters on the process outcome can be prohibitively expensive for the industry. As a result, numerical simulation of the blanking process is becoming increasingly important to gain insight into the process and study these effects.The present paper provides a novel finite element (FE) simulation procedure to predict the complete blanking cycle including sheet metal cutting, sheet metal springback, punch penetration in die, and stripping phases. A blanking force curve showing the punch force at all phases can thus be obtained. The commercial finite element code ABAQUS® has been chosen to develop this procedure using ABAQUS/Explicit® code for the cutting phase and ABAQUS/Standard® code for the remaining phases. Based on this procedure, the influence of the blanking clearance on the punch force-displacement curve and on the cut edge quality has been studied. The obtained results have been compared to previous literature results and experimental findings.

A revisit from CVD kinetics to CVD reactor: Investigating uniform growth mechanism of polysilicon in a reduction furnace

The uniform growth of polysilicon rods is essential for CVD process in the reduction furnace. Considering the complex interaction of CVD reaction and transport phenomena, the reaction engineering analysis of CVD reaction has been investigated and the requirements for the design and operation of CVD reactor are proposed concerning temperature and species concentrations. Based on the numerical simulation of CVD process in a reduction furnace with 12 pairs of rods, the non-uniform deposition is mainly attributed to the mismatching between the TCS transportation and consumption. Moreover, two measures have been attempted. One is to enhance axial mixing by increasing inlet velocity and the other is to reduce TCS consumption by reducing inlet TCS mole fraction and heat flux at the rod surface. Both measures have been confirmed beneficial for the uniform growth of the polysilicon rods.

Artificial neural network and ANFIS approaches for mechanical properties prediction and optimization of a turbine blade treated by laser shock peening

This research article covers a comprehensive investigation on the prediction and optimization of residual stresses, plastic deformations and damage induced by laser shock peening (LSP) on a thin Ti-6Al-4 V leading edge sample of a turbine blade. The study is based on a two-part approach: the first part involves a numerical simulation of the LSP process and the characterization of its effects on the material. The finite element analysis (FEA) is used to simulate the complex interactions between laser parameters, material properties and mechanical response. This numerical analysis generates valuable insights into the residual stress distribution, the plastic deformation and the potential damage within the sample being treated. Based on the numerical results, the second part highlights the novel application of the artificial neural network (ANN) and the adaptive neuro-fuzzy inference system (ANFIS) methods. By taking advantage of the strength of ANN and ANFIS, the models are able to learn accurately from all the data generated by numerical simulations, allowing them to precisely predict and optimize the effects induced by LSP: residual stresses, plastic strains and damage. This paper provides a significant contribution to the field of materials science and engineering, by offering an in-depth comprehension of the LSP process impact on Ti-6Al-4 V leading-edge turbine blade specimens. The combined utilization of numerical analysis and artificial intelligence AI-driven techniques offers a comprehensive approach to optimize the LSP process, leading to the fatigue resistance improvement and service life extension of turbine blades and other critical aerospace components. The proven capability of ANN and ANFIS enables innovative solutions in aerospace engineering and surface treatment technologies, promoting the AI implementation in materials processing and design.

Effect of Femtosecond‐Laser‐Induced Surface Textures on the Microstructure and Mechanical Properties of Mg/Ti Dissimilar Alloys Laser Lap Welds: A Numerical and Experimental Study

The strength of the joints in the Mg/Ti laser welding is difficult to meet the requirement because of the metallurgical incompatibility. This study investigates the influence of microgroove width on the diffusion of molten Mg and the mechanical properties of joints by laser welding Ti6Al4V and AZ31B, employing femtosecond lasers to fabricate microgrooves on the surface of Ti alloys. The optimal contact angle of 56.4° is achieved at the microgroove width of 100 μm because the leading and trailing edges of the microgroove texture can stimulate the formation of the microriveted structure, facilitating the fluidity of the liquid AZ31B. The joint's tensile–shear capability is increased to 2449.9 N, which is 2.8 times stronger compared to joints without microgroove textures, when using a microgroove width of 100 μm and a laser power of 52%. The numerical simulation of the laser welding process was implemented to analyze the temperature field and the fluid characteristics within the melt pool. In the results, it is shown that the microgroove enhanced the material exchange at the interface and accelerated the interfacial reaction, which stimulates the formation of Ti–Al and Mg–Al intermetallic compounds at the central interface of the joint and enhances the Mg/Ti metallurgical bonding.