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Records with Type: Published Article
1311. LAPSE:2024.0945
Virtual Test Beds for Image-Based Control Simulations Using Blender
June 7, 2024 (v1)
Subject: Modelling and Simulations
Keywords: digital twin, image-based control, process control.
Process systems engineering research often utilizes virtual testbeds consisting of physicsbased process models. As machine learning and image processing become more relevant sensing frameworks for control, it becomes important to address how process systems engineers can research the development of control and analysis frameworks that utilize images of physical processes. One method for achieving this is to develop experimental systems; another is to use software that integrates the visualization of systems, as well as modeling of the physics, such as three-dimensional graphics software. The prior work in our group analyzed image-based control for the small-scale example of level in a tank and hinted at some of its potential extensions, using Blender as the graphics software and programming the physics of the tank level via the Python programming interface. The present work focuses on exploring more practical applications of image-based control. Specifically, in this work, we first uti... [more]
1312. LAPSE:2024.0944
Quality of Mixedness Using Information Entropy in a Counter-Current Three-Phase Bubble Column
June 7, 2024 (v1)
Subject: Process Design
Keywords: information entropy, intrinsic mass transfer, mass transfer efficiency, mixedness, slurry bubble column.
Knowledge of mixing phenomena is of great value in the mineral and other chemical and biochemical industries. This work aims to analyze the quality of mixedness (QM), the intrinsic mass transfer (MT) number, and the MT efficiency based on information entropy theory in the counter-current microstructured slurry bubble column. A thorough analysis is conducted to assess the effects of particle loading, gas and slurry velocity, and axial variation on the QM. The range of gas velocity, slurry velocity, particle size, and particle loading was 0.011−0.075 m/s, 0.018−0.058 m/s, 242.72−408.31 μm, and 15.54−88.94 kg/m3, respectively. QM is a time-dependent parameter, and the concept of contact time has been used for scale-up purposes. The maximum QM was achieved at dimensionless times of 0.40 × 10−3, 0.15 × 10−3, and 0.85 × 10−3 for the maximum superficial gas velocity, particle loading, and axial height, respectively. The gas velocity positively influenced both the intrinsic MT number and its e... [more]
1313. LAPSE:2024.0943
Biofilm Formation in Water Distribution Systems
June 7, 2024 (v1)
Subject: Materials
Keywords: chlorine-resistant bacteria (CRB), DWDS, HDPE, pipes, Pseudomonas, PVC.
A biofilm is a biologically active matrix attached to the surface of cells and their extracellular products. As they are a mixture of many microorganisms, the microbiological activity of biofilms varies according to their position in the aggregate. With particular emphasis on drinking water distribution systems, this review focuses on the process of biofilm formation, associated bacteria, chlorine resistance of bacteria, and the predominant surface materials. We have compiled studies on the bacteria in drinking water distribution systems and their interactions with biofilm formation on different materials, and we also analysed the chlorine-resistant bacteria and their problems in the water networks. The materials used in the drinking water network are significantly affected by the disinfection method used to produce the biofilm that adheres to them. Some studies propose that the material is inconsequential, with the disinfection process being the most significant factor. Studies sugges... [more]
1314. LAPSE:2024.0942
Modeling of Quantitative Characterization Parameters and Identification of Fluid Properties in Tight Sandstone Reservoirs of the Ordos Basin
June 7, 2024 (v1)
Subject: System Identification
Keywords: fluid property identification, logging interpretation, model, siliciclastic reservoirs, tight sandstone, unconventional petroleum resources.
The Ordos Basin has abundant resources in its tight sandstone reservoirs, and the use of well logging technology stands out as a critical element in the exploration and development of these reservoirs. Unlike conventional reservoirs, the commonly used interpretation models are not ideal for evaluating tight sandstone reservoirs through logging. In order to accurately evaluate parameters and identify fluid properties in the tight sandstone reservoirs of the Ordos Basin, we propose the adaption of conventional logging curves. This involves establishing an interpretation model that integrates the response characteristics of logging curves to tight sandstone reservoirs in accordance with the principles of logging. In this approach, we create interpretation models specifically for shale content, porosity, permeability, and saturation within the tight sandstone reservoir. Using the characteristics of the logging curves and their responses, we apply a mathematical relationship to link these p... [more]
1315. LAPSE:2024.0941
Research on the Optimization of a Diesel Engine Intercooler Structure Based on Numerical Simulation
June 7, 2024 (v1)
Subject: Modelling and Simulations
Keywords: Computational Fluid Dynamics, grey correlation theory, intercoolers, porous media models.
As a device for cooling charged air before it enters the cylinder, the intercooler is an indispensable part of the regular operation of a booster diesel engine. To solve the problem of the insufficient cooling performance of an intercooler for a high-power supercharged diesel engine, in this study, the flow field in the intercooler is simulated using the computational fluid dynamics (CFD) model of porous media, and the performance data measured using the steady flow test bench are used to provide boundary conditions for the calculation. The effects of the charged air mass flow rate and the tube bundle’s transverse spacing on the heat dissipation performance of the intercooler are analyzed and compared. The calculation results show that, under the condition of satisfying the regular operation of the diesel engine, the heat transfer coefficient of the intercooler heat dissipation belt increases with the increase in air mass flow and the spacing of cooling pipes, and the heat transfer coe... [more]
1316. LAPSE:2024.0940
Experimental Study on Gas−Liquid Two-Phase Flow Upstream and Downstream of U-Bends
June 7, 2024 (v1)
Subject: Process Monitoring
Keywords: flow pattern, pressure pulsation, two-phase flow, U-bend.
In this study, the influence of U-bends on the flow and pressure propagation characteristics of a gas−liquid two-phase flow in upstream and downstream straight pipes was investigated experimentally. The superficial velocities of the gas and liquid are 0.18−25.11 m/s and 0.20−1.98 m/s, respectively, covering plug flow, slug flow, and annular flow. The experiments were conducted in U-tubes with inner diameters of 9 mm and 12 mm and with a curvature ratio of 8.33. The U-tube was C-shaped. The pressure fluctuations at the axial measurement points of the straight tubes were measured. Flow images of the distal straight tubes and U-bends were obtained. The disturbance from U-bends in the two-phase flow in the vicinity of the bend is very obvious. The perturbation from U-bends in the fluid in the adjacent straight tubes is highly related to the incoming flow pattern. The slug flow has the most significant influence, whereas the effects of the plug and annular flows are small. Fundamentally, it... [more]
1317. LAPSE:2024.0939
Multi-Criteria Optimization Conditions for the Recovery of Bioactive Compounds from Levisticum officinale WDJ Koch Roots Using Green and Sustainable Ultrasound-Assisted Extraction
June 7, 2024 (v1)
Subject: Food & Agricultural Processes
Keywords: antioxidant, Extraction, flavonoids, lovage, multi-criteria design, Optimization, Pareto, polyphenols.
Given that ultrasound-assisted aqueous extraction is gaining importance within “green technology” and to increase the efficiency of extracting bioactive compounds from Levisticum officinale root waste, optimization of its parameters was undertaken. Multi-objective (multi-criteria) optimization can be an extremely promising tool not only for designing and analyzing the extraction process, but also for making process-control decisions. Therefore, the main objective of this study was to develop and optimize an environmentally friendly ultrasound-assisted extraction methodology for the aqueous extraction of bioactive compounds from the roots of Levisticum officinale, which are considered a by-product. The focus was on determining the optimal extraction conditions of the independent variables, such as solid−liquid ratio, extraction time and ultrasound power, so that the optimized extracts present the highest bioactive potential expressed in terms of levels of phenolic compounds, flavonoids,... [more]
1318. LAPSE:2024.0938
Integrated Waterflooding Effect Evaluation Methodology for Carbonate Fractured−Vuggy Reservoirs Based on the Unascertained Measure−Mahalanobis Distance Theory
June 7, 2024 (v1)
Subject: Process Control
Keywords: carbonate fractured–vuggy reservoirs, Mahalanobis distance method, modified five-scale analytical hierarchy process, unascertained measure theory, waterflooding.
The waterflooding effect evaluation of carbonate fractured−vuggy reservoirs constitutes a comprehensive multiple-information decision-making process involving quantitative unascertained measure theory. This paper establishes a novel comprehensive methodology to evaluate the waterflooding effects of carbonate fractured−vuggy reservoirs for the first time. A new evaluation grading criteria is proposed using the Mahalanobis distance method based on the multi-index comprehensive unascertained measure theory derived from a modified five-scale analytical hierarchy process−entropy weight method. The actual field data from the carbonate fractured−vuggy reservoirs and the nine evaluation indices are specifically applied to demonstrate the calculation process for the construction of the grading system model on the waterflooding effects and to verify the accuracy of the Mahalanobis distance method by comparing the calculation results with the Minkowski and Euclidean distance methods. The proposed... [more]
1319. LAPSE:2024.0937
Quantitative Analysis of Near-Infrared Spectroscopy Using the BEST-1DConvNet Model
June 7, 2024 (v1)
Subject: Materials
Keywords: Bayesian optimization, chemometric predictions, convolutional neural networks (CNN), near-infrared spectroscopy (NIRS), quantitative analysis, support vector machine (SVM).
In the quest for enhanced precision in near-infrared spectroscopy (NIRS), in this study, the application of a novel BEST-1DConvNet model for quantitative analysis is investigated against conventional support vector machine (SVM) approaches with preprocessing such as multiplicative scatter correction (MSC) and standard normal variate (SNV). We assessed the performance of these methods on NIRS datasets of diesel, gasoline, and milk using a Fourier Transform Near-Infrared (FT-NIR) spectrometer having a wavelength range of 900−1700 nm for diesel and gasoline and 4000−10,000 nm for milk, ensuring comprehensive spectral capture. The BEST-1DConvNet’s effectiveness in chemometric predictions was quantitatively gauged by improvements in the coefficient of determination (R2) and reductions in the root mean square error (RMSE). The BEST-1DConvNet model achieved significant performance enhancements compared to the MSC + SNV + 1D + SVM model. Notably, the R2 value for diesel increased by approximat... [more]
1320. LAPSE:2024.0936
In-Situ and Ex-Situ Processes during Production, Transportation and Refinery of Heavy Oil
June 7, 2024 (v1)
Subject: Energy Systems
Heavy oil and natural bitumen are expected to be alternatives to the depleting conventional crude oil resources for the coming decades, mainly due to their sustainability, safety and huge number of reserves worldwide [...]
1321. LAPSE:2024.0935
Evaluation of Saturation Interpretation Methods for Ultra-Low Permeability Argillaceous Sandstone Gas Reservoirs: A Case Study of the Huangliu Formation in the Dongfang Area
June 7, 2024 (v1)
Subject: Numerical Methods and Statistics
Keywords: argillaceous sandstone gas reservoir, conductivity characteristics, gas saturation, Huangliu formation, principal component analysis, reservoir classification.
Ultra-low permeability argillaceous sandstone reservoirs have become a significant focus for exploration and development. Saturation is a crucial parameter in evaluating such reservoirs. Due to the low porosity, low permeability, complex pore structure, and strong heterogeneity in ultra-low permeability argillaceous sandstone reservoirs, traditional evaluation methods are unable to achieve the required level of interpretation accuracy. To improve the accuracy of gas saturation calculations in ultra-low permeability argillaceous sandstone gas reservoirs, the conductivity characteristics of the ultra-low permeability argillaceous sandstone gas reservoirs in the Huangliu Formation in the Dongfang area, China, were analyzed through rock physics experimental data and geological information. The results revealed the clay content in the study area to range from 6% to 33.4%. Influenced by burial depth and temperature, kaolinite and montmorillonite transform into illite and chlorite, and the ca... [more]
1322. LAPSE:2024.0934
A Comprehensive Review of Microgrid Energy Management Strategies Considering Electric Vehicles, Energy Storage Systems, and AI Techniques
June 7, 2024 (v1)
Subject: Energy Management
Keywords: Artificial Intelligence, demand-side management, electric vehicles, energy storage system, microgrid, optimization algorithms, renewable energy resources, smart grid.
The relentlessly depleting fossil-fuel-based energy resources worldwide have forbidden an imminent energy crisis that could severely impact the general population. This dire situation calls for the immediate exploitation of renewable energy resources to redress the balance between power consumption and generation. This manuscript confers about energy management tactics to optimize the methods of power production and consumption. Furthermore, this paper also discusses the solutions to enhance the reliability of the electrical power system. In order to elucidate the enhanced reliability of the electrical system, microgrids consisting of different energy resources, load types, and optimization techniques are comprehensively analyzed to explore the significance of energy management systems (EMSs) and demand response strategies. Subsequently, this paper discusses the role of EMS for the proper consumption of electrical power considering the advent of electric vehicles (EVs) in the energy ma... [more]
1323. LAPSE:2024.0933
Study on Main Factors Controlling Development Performance of Heterogeneous Composite Flooding in Post-Polymer Flooding Reservoir
June 7, 2024 (v1)
Subject: Process Control
Keywords: controlling factors for parameter allocation, development performance, heterogeneous composite flooding, post-polymer flooding reservoir.
Heterogeneous composite flooding has performed well with regard to enhanced oil recovery after polymer flooding in recent years. In order to significantly increase oil recovery, the development parameters should be designed differently for each well. However, it is difficult to rapidly allocate development parameters through the lowering of computational costs. Therefore, the authors of this paper carried out research to clarify the main controlling factors of parameter allocation. Firstly, the numerical simulation domain was separated into several regions, with injection wells and production wells at the center of each region. The statistical parameters of each region were calculated. Then, the water injection rate, liquid production rate, and chemical agent concentration were allocated based on the proportion of statistical parameters in each region. A large number of development schemes were designed by combining different injection and production allocations that were calculated ba... [more]
1324. LAPSE:2024.0932
Evaluation of Key Success Factors in the Visual Optimization of the 3D Forming of Soil-Shaping Ability
June 7, 2024 (v1)
Subject: Optimization
Keywords: 3D forming, Delphi technique, forming ability, manufacturing process, optimized design, soil shaping.
Improving the quality of the manufacturing process is an important goal of professional technicians. This study systematically explored the key success factors in the product-forming ability and visual optimization of 3D forming in the clay-shaping process through actual manufacturing and implementation. The purpose of this study was to identify the forming technology and technical indicators that can successfully achieve a high degree of completeness and maturity in the manufacturing process, increasing the shaping performance of the end products and enabling the evaluation of optimization. In this study, we evaluated soil shaping, material use, the manufacturing process, and product forming. The key success factors were studied and analyzed via expert interviews. The research and analysis were summarized into 4 dimensions with 48 sub-dimensions. These included: (1) soil material, with 12 sub-dimensions; (2) the design concept, with 12 sub-dimensions; (3) the prototype process, compri... [more]
1325. LAPSE:2024.0931
Using a Machine Learning Regression Approach to Predict the Aroma Partitioning in Dairy Matrices
June 7, 2024 (v1)
Subject: Food & Agricultural Processes
Keywords: aroma release, explainable artificial intelligence, food reformulation, Machine Learning, regression.
Aroma partitioning in food is a challenging area of research due to the contribution of several physical and chemical factors that affect the binding and release of aroma in food matrices. The partition coefficient measured by the Kmg value refers to the partition coefficient that describes how aroma compounds distribute themselves between matrices and a gas phase, such as between different components of a food matrix and air. This study introduces a regression approach to predict the Kmg value of aroma compounds of a wide range of physicochemical properties in dairy matrices representing products of different compositions and/or processing. The approach consists of data cleaning, grouping based on the temperature of Kmg analysis, pre-processing (log transformation and normalization), and, finally, the development and evaluation of prediction models with regression methods. We compared regression analysis with linear regression (LR) to five machine-learning-based regression algorithms:... [more]
1326. LAPSE:2024.0930
Multi-Mode Control of a Hybrid Transformer for the Coordinated Regulation of Voltage and Reverse Power in Active Distribution Network
June 7, 2024 (v1)
Subject: Energy Management
Keywords: active distribution network, hybrid transformer, multi-mode control, reverse power flow, topology, voltage regulation.
The unprecedented growth of distributed renewable generation is changing the distribution network from passive to active, resulting in issues like reverse power flow, voltage violations, malfunction of protection relays, etc. To ensure the reliable and flawless operation of active distribution networks, an electrical device enabling active network management is necessary, and a hybrid distribution transformer offers a promising solution. This study introduces a novel hybrid transformer topology and multi-mode control strategy to achieve coordinated voltage and reverse power regulation in active distribution networks. The proposed hybrid transformer combines conventional transformer windings with a partially rated SiC-MOSFET-based back-to-back converter, reducing additional investment costs and enhancing system reliability. A multi-mode control strategy is proposed to facilitate the concurrent reverse power control and voltage violation mitigation of the presented hybrid transformer, al... [more]
1327. LAPSE:2024.0929
Heteroatom-Doped Carbon-Based Catalysts Synthesized through a “Cook-Off” Process for Oxygen Reduction Reaction
June 7, 2024 (v1)
Subject: Materials
Keywords: “cook-off” process, heteroatom doping, metal-free catalyst, oxygen reduction reaction.
The development of efficient and low-cost non-metallic catalysts is of great significance for the oxygen reduction reaction (ORR) in fuel cells. Heteroatom-doped carbon-based catalysts are one of the popular candidates, although their preparation method is still under exploration. In this work, single (CS)-, double (NCS)-, and triple (NBCS)-heteroatom-doped carbon-based catalysts were successfully prepared by a “cook-off” process. The morphology, elemental composition, and bonding structure of the catalysts were investigated by SEM, TEM, Raman spectra, BET, and XPS. ORR catalytic performance measurements suggested an activity trend of CS < NCS < NBCS, and NBCS demonstrated better methanol resistance and slightly higher stability than the commercial Pt/C catalyst, as evaluated with both rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) systems. The mechanism for the promoted performance was also proposed based on the conductivity of the catalysts. In this paper... [more]
1328. LAPSE:2024.0928
A Numerical Simulation of the Seismic Performance and Residual Stress of Welded Joints in Building Steel Structures Based on the Finite Element Method
June 7, 2024 (v1)
Subject: Modelling and Simulations
Keywords: finite element analysis, numerical simulation, residual stress, steel structure, welded joint.
With the development of society and urbanization, higher requirements have been put forward for the safety and seismic resistance of building structures. The fatigue strength and seismic performance of welded joints have received close attention, especially as a crucial part of building steel structure. This study used the finite element simulation method to analyze the stress-strain of welded joints in building steel structures, and explore the influence of residual stress on their seismic performance. A stress-strain calculation model for welded joints in building steel structures was studied and constructed, and the accuracy of the model was verified through numerical calculation methods. The results showed that the residual stress peaks of the horizontal and vertical directions of the V-groove welded joint structure were 475 MPa and 325 MPa, respectively, and the longitudinal residual stress peaks were 525 MPa and 425 MPa, respectively. The seismic performance of four different ste... [more]
1329. LAPSE:2024.0927
Economic Modelling of Mixing Hydrogen with Natural Gas
June 7, 2024 (v1)
Subject: Energy Systems
Keywords: CO2 reduction, economic evaluation, heat values, Hydrogen, Natural Gas.
As global efforts intensify to transition toward cleaner and more sustainable energy sources, the blending of hydrogen with natural gas emerges as a promising strategy to reduce carbon emissions and enhance energy security. This study employs a systematic approach to assess the economic viability of hydrogen blending, considering factors such as gas costs and heat values. Various hydrogen blending scenarios are analyzed to determine the optimal blend ratios, taking into account both technical feasibility and economic considerations. The study discusses potential economic benefits, challenges, and regulatory implications associated with the widespread adoption of hydrogen−natural gas mixtures. Furthermore, the study explores the impact of this integration on existing natural gas infrastructure, exploring the potential for enhanced energy storage and delivery. The findings of this research contribute valuable insights to policymakers, industry stakeholders, and researchers engaged in the... [more]
1330. LAPSE:2024.0926
CFD Modeling and Experimental Validation of the Flow Processes of an External Gear Pump
June 7, 2024 (v1)
Subject: Modelling and Simulations
Keywords: computational fluid dynamics (CFD), external gear pump, flow processes.
This article presents computational fluid dynamics (CFD) modeling of the flow processes at a certain specimen of an external gear pump. The purpose of the developed two-dimensional (2D) CFD model is to carry out a numerical study to obtain the main characteristics of the pump flow rate, especially the flow rate as a function of the pressure and the flow rate as a function of the time. A numerical study was carried out at forty-two different operating modes that were expressed as a variation of two parameters: rotational frequency (950−1450 min−1) and pressure (5−150 bar). The validation of the numerical results was carried out through an experimental study. For this purpose, a laboratory experimental setup equipped with a modern data acquisition (DAQ) system was designed and implemented. It allows the gear pump to be tested at the same operating modes as the numerical study. A validation analysis was performed by comparing the numerical and experimental results using the average relati... [more]
1331. LAPSE:2024.0925
Modeling of Triphenyl Phosphate Surfactant Enhanced Drying of Polystyrene/p-Xylene Coatings Using Artificial Neural Network
June 7, 2024 (v1)
Subject: Materials
Keywords: ANN modeling, poly(styrene), surfactant enhanced drying, thin films, triphenyl phosphate.
The drying process of polymeric coatings, particularly in the presence of surfactants, poses a complex challenge due to its intricate dynamics involving simultaneous heat and mass transfer. This study addresses the inherent complexity by employing Artificial Neural Networks (ANNs) to model the surfactant-enhanced drying of poly(styrene)-p-xylene coatings. A substantial dataset of 16,258 experimentally obtained samples forms the basis for training the ANN model, showcasing the suitability of this approach when ample training data is available. The chosen single-layer feed-forward network with backpropagation adeptly captures the non-linear relationships within the drying data, providing a predictive tool with exceptional accuracy. Our results demonstrate that the developed ANN model achieves a precision level exceeding 99% in predicting coating weight loss for specified input values of time, surfactant amount, and initial coating thickness. The model’s robust generalization capability e... [more]
1332. LAPSE:2024.0924
Design and Simulation of End Effector for Young-Pear-Bagging Robot
June 7, 2024 (v1)
Subject: Modelling and Simulations
Keywords: bagging of juvenile pears, simulation and analysis, structural design.
In order to address the time-consuming and labor-intensive challenges as well as the suboptimal operational quality encountered in the conventional processes of fruit bagging within expansive orchards, an innovative end-of-bagging actuator is proposed, which can be installed on a fruit-production robot. Due to the excessive power sources required to complete the bagging operation, while also taking into account the quality and cost of the end effector, we have implemented a clutch transmission system to control individual motors, thereby achieving efficient bag-opening and collection actions. Through kinematic analysis of the bagging end effector, the optimal bag opening size is determined to be 40.3372 mm, with a deviation of 0.1428 mm from the design target and an error rate of 0.35%. This ensures the desired bag size for bagging juvenile fruits. Moreover, a dynamic simulation model comprising rigid drive components and a flexible clutch was developed. The simulation results demonstr... [more]
1333. LAPSE:2024.0923
Xylanase Production by Cellulomonas phragmiteti Using Lignocellulosic Waste Materials
June 7, 2024 (v1)
Subject: Materials
Keywords: bacterial enzymes, enzyme fermentation, enzyme stability, hemicellulases, waste valorization, xylanase characterization.
Lignocellulosic biomass holds promise as a renewable feedstock for various applications, but its efficient conversion requires cost-effective degradation strategies. The main objective of this study was to investigate the effect of the growth conditions of Cellulomonas phragmiteti in the production of (hemi)cellulosic supernatants. To meet this aim, different lignocellulosic residues were used as carbon sources for growth using defined mineral or nutritive culture media. Cell-free culture supernatants with xylanolytic activity were produced in all the conditions evaluated, but the highest xylanase activity (15.3 U/mL) was achieved in Luria−Bertani (LB) medium containing 1% waste paper. Under these conditions, almost negligible β-glucosidase, cellobiohydrolase, β-xylosidase, and α-arabinofuranosidase activity was detected. The xylanolytic supernatant showed tolerance to salt and displayed maximal catalytic efficiency at pH 6 and 45 °C, along with good activity in the ranges of 45−55 °C... [more]
1334. LAPSE:2024.0922
Temperature Field Simulation and Experimental Confirmation of Laser Cladding High-Entropy Alloy Coating on Cr12MoV
June 7, 2024 (v1)
Subject: Modelling and Simulations
Keywords: double ellipsoidal heat source model, experimental confirmation, high-entropy alloy, laser cladding, temperature field simulation.
In order to meet the mechanical property of the die steel, this study used laser cladding to prepare a high-entropy alloy coating on Cr12MoV. A finite element method using a double ellipsoidal heat source model is proposed to simulate the evolution of the temperature field in laser cladding. The simulation results showed that with the increase in the power, the peak temperature of the molten pool increased from 2005.5 °C to 2357.4 °C, and the depth of the molten pool increased from 1.60 mm to 2.04 mm. The coating with the laser power of 1600 W had a good macroscopic quality and high lattice distortion (2.43 × 10−2). Due to the increase in laser energy density, the size of equiaxed crystals gradually increased from 1400 W to 1700 W. Under the comprehensive effect of the solution and fine grain strengthening, the coating with the power of 1600 W had a higher average microhardness (600 HV), which is 150% higher than that of the substrate. The experiment results further confirmed the accur... [more]
1335. LAPSE:2024.0921
Effects of Viscosity Law on High-Temperature Supersonic Turbulent Channel Flow for Chemical Equilibrium
June 7, 2024 (v1)
Subject: Numerical Methods and Statistics
Keywords: chemical equilibrium, direct numerical simulation, instantaneous structure, turbulence statistics, viscosity law.
Direct numerical simulations of temporally evolving high-temperature supersonic turbulent channel flow for chemical equilibrium were conducted with a Mach number of 3.0, a Reynolds number of 4880, and a wall temperature of 1733.2 K to investigate the influence of the viscosity law. The mean and fluctuating viscosity for the mixture rule is higher than that for Sutherland’s law, whereas an opposite trend is observed in the mean temperature, mean pressure, and dissociation degree. The Trettel and Larsson transformed mean velocity, the Reynolds shear stress, the turbulent kinetic energy budget, and the turbulent Prandtl number are insensitive to the viscosity law. The semilocal scaling that take into account local variation of fluid characteristics better collapses the turbulent kinetic energy budget. The modified strong Reynolds analogies provide reasonably good results for the mixture rule, which are better than those for Sutherland’s law. The streamwise and spanwise coherencies for the... [more]
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