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Records with Subject: Process Operations
Showing records 1 to 25 of 109. [First] Page: 1 2 3 4 5 Last
The Impact of Uncertainty Factors on the Decision-Making Process of Logistics Management
Łukasz Marzantowicz
July 2, 2020 (v1)
Keywords: conditions of uncertainty, logistic decisions, logistics management
The article is a contribution to the discussion on the possibilities of effective logistic decisions under the conditions of uncertainty. Variable and unpredictable factors, which create the conditions of uncertainty, not only directly affect logistic processes (positive or negative impact), but can also be a determinant of making decisions. Logistics management, because it is referred to in the context of decision-making, is currently defined by the quality of management decisions taken, including factors which often constitute only partially quantifiable sets. The main goal of the article is to show the strength of the dependence between the occurrence of uncertainty factors and the type of decision. On the basis of decision-making theory, the types of decisions were defined, and then a set of factors that are most important for a given type of decision was selected. The results of the analysis allowed the strength of the influence of uncertainty factors on making logistics decisions... [more]
Infrared Spectroscopic Analysis of the Inorganic Deposits from Water in Domestic and Technical Heat Exchangers
Johannes Kiefer, Alexander Stärk, Agnita Lynda Kiefer, Heike Glade
June 23, 2020 (v1)
Keywords: boiler, carbonate, chemical analysis, debris, Fourier-transform infrared spectroscopy, heat exchanger, scale, sulfate
The deposition of insoluble inorganic substances on heat exchanger surfaces has a strong negative influence on the heat transfer and thus on the performance of the apparatus and the process. The analysis of the deposits is a crucial step towards the development of suitable technologies for scaling mitigation and prevention. Such analysis, however, is challenging and often requires advanced instrumentation and sample preparation. To overcome this problem, we present a straightforward analytical approach based on Fourier-transform infrared (FTIR) spectroscopy. We demonstrate that FTIR spectroscopy is a powerful tool for the chemical analysis of inorganic deposits. For example, it can identify the common anions in scales such as sulfates and carbonates. It can even distinguish between salts with the same anion but different cations such as calcium and sodium. Test measurements are performed on the deposits from a domestic water cooker and from the evaporator of a seawater desalination pil... [more]
An Application of a Novel Technique for Assessing the Operating Performance of Existing Cooling Systems on a University Campus
Elnazeer Ali Hamid Abdalla, Perumal Nallagownden, Nursyarizal Bin Mohd Nor, Mohd Fakhizan Romlie, Sabo Miya Hassan
June 23, 2020 (v1)
Keywords: accelerated particle swarm optimization (APSO), adaptive neuro-fuzzy inference system (ANFIS), coefficient of performance (COP), cooling capacity, fuzzy C-means clustering (FCM), fuzzy clustering subtractive (FCS), particle swarm optimization (PSO), power consumption
Optimal operation is an important aspect of energy efficiency that can be employed to reduce power consumption. In cooling systems, the chillers consume a large amount of electricity, especially if they are not optimally operated, therefore, they cannot produce the required or rated cooling load capacity. The objective of this paper is to improve coefficient of performance (COP) for the operation of chillers and to reduce power consumption. Two contributions in this work are: (1) the prediction of a model by using Adaptive Neuro-Fuzzy Inference System (ANFIS)-based Fuzzy Clustering Subtractive (FCS), and (2) the classification and optimization of the predicted models by using an Accelerated Particle Swarm Optimization (APSO) algorithm. Particularly, in contribution (1), two models are developed to predict/assess power consumption and cooling load capacity. While in contribution (2), the predictive model’s data obtained are used to classify the operating performance of the chiller and t... [more]
The Application of Cyber Physical System for Thermal Power Plants: Data-Driven Modeling
Yongping Yang, Xiaoen Li, Zhiping Yang, Qing Wei, Ningling Wang, Ligang Wang
June 23, 2020 (v1)
Keywords: cyber physical system, data mining, online monitoring and control, physical knowledge, thermal power plants
Optimal operation of energy systems plays an important role to enhance their lifetime security and efficiency. The determination of optimal operating strategies requires intelligent utilization of massive data accumulated during operation or prediction. The investigation of these data solely without combining physical models may run the risk that the established relationships between inputs and outputs, the models which reproduce the behavior of the considered system/component in a wide range of boundary conditions, are invalid for certain boundary conditions, which never occur in the database employed. Therefore, combining big data with physical models via cyber physical systems (CPS) is of great importance to derive highly-reliable and -accurate models and becomes more and more popular in practical applications. In this paper, we focus on the description of a systematic method to apply CPS to the performance analysis and decision making of thermal power plants. We proposed a general... [more]
Investigation and Analysis of a Hazardous Chemical Accident in the Process Industry: Triggers, Roots, and Lessons Learned
Jianhao Wang, Gui Fu, Mingwei Yan
June 23, 2020 (v1)
Keywords: 24Model, cause analysis, hazardous chemical accident, individual, organization
This paper performs an in-depth investigation and analysis on a catastrophic hazardous chemical accident involving domino effects in China based on an emerging accident causation model—the 24Model. The triggers and roots of the incident from the individual and organizational levels have been identified and several useful lessons have been summarized to avoid similar mistakes. This accident began with a leak of vinyl chloride caused by the failure of the gas holder’s bell housing and the operators’ mishandling. Leaked vinyl chloride was ignited by a high-temperature device in the process of diffusion and the fire quickly spread to the illegally parked vehicles. Several organizations were involved in this accident, and the chemical company should bear the main responsibility for it, and shall establish and implement an effective safety management system in its organizational structure and staffing, facilities management, hazards identification, emergency disposal, etc., to improve safety... [more]
Application of Evolutionary Game Theory in Safety Management of Chemical Production
Qiusheng Song, Peng Jiang, Song Zheng
June 23, 2020 (v1)
Keywords: chemical production, evolutionary game, safety management
The chemical industry is essential in the social economy, and the issue of production safety has aroused widespread concern. Chemical safety incidents occupy the headlines from time to time, and chemical production safety management is particularly important. This paper presents an application model based on evolutionary game theory in the assessment and analysis of chemical production safety management. The model uses evolutionary game theory to construct a strategic interactive payoff matrix between the management department of a chemical plant and the chemical plant using a replicated dynamic equation to analyze their strategic interaction and to reveal the evolution of behavioral strategy selection. The evolution results were verified and simulated. The application of this model provides an effective safety management basis and recommendations for the management of chemical plants, providing a foundation for the safe production and healthy development of chemical plants.
Influence of Selected Parameters and Different Methods of Implementing Vacuum Impregnation of Apple Tissue on Its Effectiveness
Tomasz Guz, Leszek Rydzak, Marek Domin
June 10, 2020 (v1)
Keywords: apple tissue, impregnation method, vacuum impregnation
The study provides comprehensive information on the vacuum impregnation process applied to plant materials. It aims (in traditional applications) to ensure impermeability and elimination of porosity of various materials. The process substantially accelerates mass transfer in the liquid−solid system. The study describes the course of the process and accompanying phenomena as well its effects on plant tissues. The aim of the investigations was to determine the impact of some impregnation parameters (pressure, pressure change rate, vacuum maintenance time, relaxation time, and the coefficient of impregnating liquid viscosity) and the mode of impregnation (wet, dry, cyclic wet) on the degree of filling the plant tissue with the impregnating solution. Jonagold apples were used as the study material. The investigations have revealed that changes in the vacuum impregnation parameters (vacuum maintenance time, relaxation time, pressure change rate in the system) and the impregnation method do... [more]
Integrated Method of Monitoring and Optimization of Steam Methane Reformer Process
Nenad Zečević, Nenad Bolf
June 10, 2020 (v1)
Keywords: ammonia production, numerical modelling, Simulation, steam methane reforming
Reforming of natural gas with steam represents the most energy-intensive part of ammonia production. An integrated numerical model for calculating composition of primary reforming products with cross-checking of outlet methane molar concentration, heat duty, maximum tube wall temperature, tube pressure drops, and approach to equilibrium was set up involving production parameters. In particular, the model was used for continuous monitoring and optimization of a steam methane reformer (SMR) catalyst in ammonia production. The calculations involve the solution of material and energy balance equations along with reaction kinetic expressions. Open source code based on Matlab file was used for modelling and calculation of various physical properties of the reacting gases. One of the main contributions is development of the rapid integrated method for data exchange between any distributed control system (DCS) and the model to accomplish continuous monitoring and optimization of SMR catalyst a... [more]
Evaluating Pre- and Post-Coagulation Configuration of Dissolved Air Flotation Using Response Surface Methodology
Emmanuel Kweinor Tetteh, Sudesh Rathilal
June 3, 2020 (v1)
Keywords: coagulants, Coagulation, dissolved air flotation, oil refinery wastewater, response surface methodology
The effects of coagulation-dissolved air flotation (DAF) process configuration was studied on oil refinery wastewater. The configuration was done in two ways: acid-coagulation-DAF (pre-treatment) and acid-DAF-coagulation (post-treatment). Two different cationic and polymeric organic coagulants were employed in this study to compare their treatability performance with the two aforementioned configurations. All the coagulants applied before the DAF were found to be effective, with over 85% more contaminant removal efficiency than their post-treatment. Alum, being the most cost-effective coagulant, was then employed with response surface methodology (RSM) to obtain the optimum conditions. These include a coagulant dosage of 100 mg/L, air saturator pressure of 375 kPa and air−water ratio of 10% vol/vol corresponding to a desirability of 92% for the removal of oily pollutants from a local South Africa oil refinery’s wastewater. With the response quadratic models that were developed, the opt... [more]
Data-Driven Robust Optimal Operation of Thermal Energy Storage in Industrial Clusters
Mandar Thombre, Zawadi Mdoe, Johannes Jäschke
May 22, 2020 (v1)
Keywords: data-driven, energy-efficiency, industrial clusters, robust model predictive control, thermal energy storage, uncertainty
Industrial waste heat recovery is an attractive option having the simultaneous benefits of reducing energy costs as well as carbon emissions. In this context, thermal energy storage can be used along with an optimal operation strategy like model predictive control (MPC) to realize significant energy savings. However, conventional control methods offer little robustness against uncertainty in terms of daily operation, where supply and demand of energy in the cluster can vary significantly from their predicted profiles. A major concern is that ignoring the uncertainties in the system may lead to the system violating critical constraints that affect the quality of the end-product of the participating processes. To this end, we present a method to make optimal energy storage and discharge decisions, while rigorously handling this uncertainty. We employ multivariate data analysis on historical industrial data to implement a multistage nonlinear MPC scheme based on a scenario-tree formulatio... [more]
A Review of Exergy Based Optimization and Control
Corey James, Tae Young Kim, Robert Jane
May 22, 2020 (v1)
Keywords: control, Energy, Exergy, Optimization
This work presents a critical review of the use of exergy based control and optimization for efficiency improvements in energy networks, with a background of exergy based analysis given for context. Over the past three decades, a number of studies using exergy were conducted to gain a performance advantage for high energy consumption systems and networks. Due to their complexity and the increased scale of the systems, the opportunity to misuse energy inevitability leads to inefficient operations. The studies accomplished in this area are grouped into either control or optimization to highlight each method’s ability to minimize system irreversibilities that lead to exergy destruction. The exergy based optimization and control studies featured demonstrate substantial improvements (as high as 40%) over traditional methods based on the first law of thermodynamics. This paper reviews the work completed in the area of exergy based optimization and control as of the end of September 2019, out... [more]
Power Plant Optimisation—Effective Use of the Nelder-Mead Approach
Paweł Niegodajew, Maciej Marek, Witold Elsner, Łukasz Kowalczyk
May 22, 2020 (v1)
Keywords: advanced ultra-supercritical power plant, direct search, gradient free optimisation, Nelder-Mead, simplex search, thermal cycle
This paper demonstrates the use of a combined software package including IPSEpro and MATLAB in the optimisation of a modern thermal cycle. A 900 MW power plant unit (operating at ultra-supercritical conditions) was considered as the study object. The Nelder-Mead simplex-based, direct search method was used to increase power plant efficiency and to find the optimal thermal cycle configuration. As the literature reveals, the Nelder-Mead approach is very sensitive to the simplex size and to the choice of method coefficients, i.e., reflection, expansion and contraction. When these coefficients are improperly chosen, the finding of the optimal solution cannot be guaranteed, particularly in such complex systems as thermal cycles. Hence, the main goal of the present work was to demonstrate the capability of an integrated software package including IPSEpro, MATLAB and MS Excel in the optimisation process of a complex thermal cycle, as well as to examine the effectiveness of the most popular se... [more]
Optimizing the Extraction of Polysaccharides from Bletilla ochracea Schltr. Using Response Surface Methodology (RSM) and Evaluating their Antioxidant Activity
Bulei Wang, Yan Xu, Lijun Chen, Guangming Zhao, Zeyuan Mi, Dinghao Lv, Junfeng Niu
May 22, 2020 (v1)
Keywords: antioxidant activities, Bletilla ochracea Schltr. polysaccharide, response surface methodology (RSM)
Bletilla ochracea Schltr. polysaccharides (BOP) have a similar structure to Bletilla striata (Thunb.) Reichb.f. (Orchidaceae) polysaccharides (BSP). Therefore, BOP can be considered as a substitute for BSP in the food, pharmaceuticals and cosmetics fields. To the best of our knowledge, little information is available regarding the optimization of extraction and antioxidant activity of BOP. In this study, response surface methodology (RSM) was firstly used for optimizing the extraction parameters of BOP. The results suggested that the optimal conditions included a temperature of 82 °C, a duration of 85 min and a liquid/material ratio of 30 mL/g. In these conditions, we received 26.45% ± 0.18% as the experimental yield. In addition, BOP exhibited strong concentration-dependent antioxidant abilities in vitro. The half-maximal effective concentration (EC50) values of BOP against 1,1-diphenyl-2-picrylhydrazyl (DPPH·), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonate) (ABTS+·), hydroxyl (... [more]
Influence of Blanching Time on Moisture, Sugars, Protein, and Processing Recovery of Sweet Corn Kernels
Mariusz Szymanek, Agata Dziwulska-Hunek, Wojciech Tanaś
May 22, 2020 (v1)
Keywords: blanching, moisture, processing recovery, protein, sugars, sweetcorn
The objective of this work is to determine the influence of blanching time on moisture content, sugars, protein, and processing recovery (degree of cut corn) of sweet corn kernels. Sweetcorn cobs of the Jubilee variety were blanched in the water at the temperature 85 °C during the period of 2, 4, 6, and 8 min. Non-blanched cobs were used as control samples. Blanched cobs were made subject to a mechanical process of cutting-off the kernels. It was stated that the blanching time has significant statistical influence on the content of moisture, sugars, and protein in kernel as well as on the quantity of the cut-off kernel mass.
Effect of Hydraulic Retention Time on Anaerobic Baffled Reactor Operation: Enhanced Biohydrogen Production and Enrichment of Hydrogen-producing Acetogens
Fan Jiang, Zhiying Peng, Huaibo Li, Ji Li, Shuo Wang
May 22, 2020 (v1)
Keywords: anaerobic baffled reactor (ABR), biohydrogen production, biohydrogen-producing acetogens (HPA), hydraulic retention time (HRT), normal molasses wastewater
Biohydrogen production by fermentation has become a promising technology developed in the world. In this study, diluted normal molasses wastewater is used as the raw material, and biohydrogen production efficiency and operation characteristics of an anaerobic baffled reactor (ABR) are studied. The effect of hydraulic retention time (HRT) on biohydrogen production efficiency and operating characteristics of ABR is extensively discussed. Experimental results showed that methanogen residuals were still observed in the last three compartments under HRT of 24 h and COD(Chemical oxygen demand) concentration of 8000 mg/L. Meanwhile, the first three compartments presented an ethanol fermentation type. The characteristics of butyric acid fermentation in Compartment IV were also enhanced. The average removal efficiency of COD was reduced to 15.4%. The average rates of biohydrogen production and specific biohydrogen production were 12.85 and 360.22 L/kg COD, respectively. The extension of HRT was... [more]
Model-Based Real Time Operation of the Freeze-Drying Process
Carlos Vilas, Antonio A. Alonso, Eva Balsa-Canto, Estefanía López-Quiroga, Ioan Cristian Trelea
May 22, 2020 (v1)
Keywords: freeze-drying, model calibration, operational model, real time optimization
Background: Freeze-drying or lyophilization is a dehydration process employed in high added-value food and biochemical goods. It helps to maintain product organoleptic and nutritional properties. The proper handling of the product temperature during the operation is critical to preserve quality and to reduce the process duration. Methods: Mathematical models are useful tools that can be used to design optimal policies that minimize production costs while keeping product quality. In this work, we derive an operational mathematical model to describe product quality and stability during the freeze-drying process. Model identification techniques are used to provide the model with predictive capabilities. Then, the model is used to design optimal control policies that minimize process time. Results and conclusion: Experimental measurements suggest splitting the process into two subsystems, product and chamber, to facilitate the calibration task. Both models are successfully validated using... [more]
Integrated Process Design and Control for Smart Grid Coordinated IGCC Power Plants Using Economic Linear Optimal Control
Jin Zhang, Sofia Garcia Fracaro, Donald J. Chmielewski
May 8, 2020 (v1)
Keywords: economic linear optimal control, economic model predictive control, Integrated Gasification Combined Cycle (IGCC), process control, process design
The Integrated Gasification Combined Cycle (IGCC) possesses a number of advantages over traditional power generation plants, including increased efficiency, flex-fuel, and carbon capture. A lesser-known advantage of the IGCC system is the ability to coordinate with the smart grid. The idea is that process modifications can enable dispatch capabilities in the sense of shifting power production away from periods of low electricity price to periods of high price and thus generate greater revenue. The work begins with a demonstration of Economic Model Predictive Control (EMPC) as a strategy to determine the dispatch policy by directly pursuing the objective of maximizing plant revenue. However, the numeric nature of EMPC creates an inherent limitation when it comes to process design. Thus, Economic Linear Optimal Control (ELOC) is proposed as a surrogate for EMPC in the formulation of the integrated design and control problem for IGCC power plants with smart grid coordination.
Industrial Internet of Things and Fog Computing to Reduce Energy Consumption in Drinking Water Facilities
Adrian Korodi, Ruben Crisan, Andrei Nicolae, Ioan Silea
May 8, 2020 (v1)
Keywords: data analysis, fog computing, historian, Industrial Internet of Things, Industry 4.0, water industry
The industry is generally preoccupied with the evolution towards Industry 4.0 principles and the associated advantages as cost reduction, respectively safety, availability, and productivity increase. So far, it is not completely clear how to reach these advantages and what their exact representation or impact is. It is necessary for industrial systems, even legacy ones, to assure interoperability in the context of chronologically dispersed and currently functional solutions, respectively; the Open Platform Communications Unified Architecture (OPC UA) protocol is an essential requirement. Then, following data accumulation, the resulting process-aware strategies have to present learning capabilities, pattern identification, and conclusions to increase efficiency or safety. Finally, model-based analysis and decision and control procedures applied in a non-invasive manner over functioning systems close the optimizing loop. Drinking water facilities, as generally the entire water sector, ar... [more]
Near-Null Geomagnetic Field as an Innovative Method of Fruit Storage
Grzegorz Zaguła, Maria Tarapatskyy, Marcin Bajcar, Bogdan Saletnik, Czesław Puchalski, Andrzej Marczuk, Dariusz Andrejko, Jan Oszmiański
May 2, 2020 (v1)
Keywords: apples storage, chemical profile, compensation, geomagnetic field, sugars
The article presents the findings of a study investigating the effects of storing Jonagold apples for six weeks in a condition in which the vertical component of the geomagnetic field has been eliminated (near null GMF) and in control conditions representing those applied in traditional storage (i.e., in the local geomagnetic field (local GMF)). Analyses of the fruit were performed before the start of and three times during the experiment (i.e., following four, five and six weeks in storage). The contents of simple sugars were measured using the HPLC (high performance liquid chromatography) method; refractometry was applied to identify total extract; thermogravimetry was used to measure the water content, volatile substances and total ash; calorific value and intensity of respiration were examined by measuring CO2 emissions. Significant differences were found between the apples stored in the experimental and under control conditions, showing an advantage of storage in a condition with... [more]
Theoretical and Experimental Studies of a Digital Flow Booster Operating at High Pressures and Flow Rates
Chenggang Yuan, Vinrea Lim Mao Lung, Andrew Plummer, Min Pan
April 14, 2020 (v1)
Keywords: digital hydraulics, efficient fluid power, flow booster, high-speed switching valves, pressure booster, switched inertance hydraulic systems
The switched inertance hydraulic converter (SIHC) is a new technology providing an alternative to conventional proportional or servo-valve-controlled systems in the area of fluid power. SIHCs can adjust or control flow and pressure by means of using digital control signals that do not rely on throttling the flow and dissipation of power, and provide hydraulic systems with high-energy efficiency, flexible control, and insensitivity to contamination. In this article, the analytical models of an SIHC in a three-port flow-booster configuration were used and validated at high operating pressure, with the low- and high-pressure supplies of 30 and 90 bar and a high delivery flow rate of 21 L/min. The system dynamics, flow responses, and power consumption were investigated and theoretically and experimentally validated. Results were compared to previous results achieved using low operating pressures, where low- and high-pressure supplies were 20 and 30 bar, and the delivery flow rate was 7 L/m... [more]
Quantifying the Benefit of a Dynamic Performance Assessment of WWTP
Silvana Revollar, Montse Meneses, Ramón Vilanova, Pastora Vega, Mario Francisco
April 14, 2020 (v1)
Keywords: dynamic assessment of performance, environmental costs, PID control, wastewater treatment plants
In this work a comprehensive analysis of the environmental impact of the operation of a wastewater treatment plant (WWTP) using different control strategies is carried out considering the dynamic evolution of some environmental indicators and average operation costs. The selected strategies are PI (proportional integral) control schemes such as dissolved oxygen control in the aerobic zone (DO control), DO control and nitrates control in the anoxic zone (DO + NO control) and regulation of ammonium control at the end of aerobic zone (Cascade SNHSP) commonly used in WWTPs to maintain the conditions that ensure the desired effluent quality in a variable influent scenario. The main novelty of the work is the integration of potential insights into environmental impact from the analysis of dynamic evolution of environmental indicators at different time scales. The consideration of annual, bimonthly and weekly temporal windows to evaluate performance indicators makes it possible to capture sea... [more]
A Retrofit Hierarchical Architecture for Real-Time Optimization and Control Integration
Xiaochen Li, Lei Xie, Xiang Li, Hongye Su
April 1, 2020 (v1)
Keywords: extremum-seeking control, hierarchical architecture, least-squares regression, necessary conditions of optimality, optimal operation, self-optimizing control
To achieve the optimal operation of chemical processes in the presence of disturbances and uncertainty, a retrofit hierarchical architecture (HA) integrating real-time optimization (RTO) and control was proposed. The proposed architecture features two main components. The first is a fast extremum-seeking control (ESC) approach using transient measurements that is employed in the upper RTO layer. The fast ESC approach can effectively suppress the impact of plant-model mismatch and steady-state wait time. The second is a global self-optimizing control (SOC) scheme that is introduced to integrate the RTO and control layers. The proposed SOC scheme minimizes the global average loss based on the approximation of necessary conditions of optimality (NCO) over the entire operating region. A least-squares regression technique was adopted to select the controlled variables (CVs) as linear combinations of measurements. The proposed method does not require the second order derivative information,... [more]
Investigation of the Most Suitable Conditions for Dehydration of Tuckeroo (Cupaniopsis anacardioides) Fruits
Ngoc Minh Quynh Pham, Quan V. Vuong, Anh V. Le, Michael C. Bowyer, Christopher J. Scarlett
March 12, 2020 (v1)
Keywords: antioxidant, dehydration, drying, fruit, phytochemical, Tuckeroo
Tuckeroo (Cupaniopsis anacardioides) is an Australian native tree, possessing high level bioactivity and antioxidant activity. To prevent deterioration of active constituents, appropriate drying practices must be determined. This study comparatively evaluates the impact of a range of drying methods including freeze-, microwave-, vacuum-, hot air- and sun-drying on the physical, phytochemical and antioxidant characteristics of Tuckeroo fruit. Experimental results showed that the five drying methods had significant impact on the physicochemical properties and antioxidant activity of the fruits. Of the drying methods assessed, freeze drying best preserved Tuckeroo activity, recording higher total phenolic content (TPC) (81.88 mg gallic acid equivalent (GAE)/g), total flavonoids (TFC) (107.71 mg catechin equivalent (CAE)/g), proanthocyanidins (TPro) (83.86 mg CAE/g) and exhibited the strongest antioxidant capacity. However, vacuum drying at 65 kPa, 100 °C for 5 h is recommended for drying... [more]
Quality Control for Medium Voltage Insulator via a Knowledge-Informed SPSA Based on Historical Gradient Approximations
Xiangsong Kong, Jiaming Guo, Dongbin Zheng, Ji Zhang, Wei Fu
March 11, 2020 (v1)
Keywords: historical gradient approximations, knowledge-informed, medium voltage insulator, quality control, SPSA
Medium voltage insulators are essential and versatile components in electrical engineering. Quality control of the manufacturing process for the insulators has a significant role in their economic production and reliable operation. As the quality of medium voltage insulator is mainly affected by the process parameters of the automatic pressure gelation process (APG), the optimal process settings are required to achieve a satisfactory quality target. However, traditional process parameters’ optimization methods are often cumbersome and cost-consuming. Moreover, the operational cost of APG for insulator production is relatively high. Therefore, the determination of the optimal settings becomes a significant challenge for the quality control of insulators. To address the above issues, an idea of knowledge-informed optimization was proposed in this study. Based on the above idea, a knowledge-informed simultaneous perturbation stochastic approximation (SPSA) methodology was formulated to re... [more]
Influence of Eccentricity on Hydrodynamic Characteristics of Nuclear Reactor Coolant Pump under Different Cavitation Conditions
Yuanyuan Zhao, Bin Lin, Xiuli Wang, Rongsheng Zhu, Qiang Fu
February 12, 2020 (v1)
Keywords: axial force, cavitation, eccentricity, nuclear reactor coolant pump, radial force
In order to study the influence of eccentricity on hydrodynamic characteristics of nuclear reactor coolant pump under different cavitation conditions, five different schemes were obtained by analyzing and optimizing the existing structural schemes. Based on the RNG k-ε model (Renormalization Group with k-epsilon turbulence models) and two-fluid two-phase flow model, the unsteady numerical analysis and test verification of different designed schemes are carried out by using the flow field software ANSYS CFX. The results of research show that different eccentricities will affect the nuclear reactor coolant pump’s head under different cavitation conditions, and the corresponding head in the scheme with the eccentricity of 5mm under the fracture cavitation condition is lower than that of the other schemes. When the impeller rotates at a certain angle from the initial position under critical and severe cavitation conditions, the radial force acting on the rotor system will fluctuate greatly... [more]
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