Investigations on Optimal Design of a U-Tube Steam Generator

2010 ◽  
Author(s):  
Hui-min Qin ◽  
Chang-qi Yan ◽  
Meng Wang ◽  
Shi-jing He
Keyword(s):  
Optimal Design ◽  
Steam Generator ◽  
Optimization Techniques ◽  
Point Of View ◽  
Geometric Constraints ◽  
Optimal Designs ◽  
Optimal Method ◽  
Obvious Effect ◽  
Pressurized Water ◽  
Performance Point

Steam generator is one of the key equipments in the pressurized water reactor, from the performance point of view, it is necessary to apply optimization techniques to the design of the steam generator. In this work, the optimal designs of a U-tube steam generator (UTSG), taking minimization of the total volume and net weight as objective respectively, are carried out by considering thermohydraulic and geometric constraints using a complex-genetic algorithm (CGA). And the sensitivities of some parameters which influence the total volume and net weight of UTSG are also analyzed. Under the condition of constant secondary thermalhydraulic parameters of the steam generator, the optimal design indicates an obvious effect taking either the overall volume or the total weight of the steam generator as the objective. The optimization results show that the proposed optimal method is feasible and effective. And the results of optimal designs and sensitivity analysis would provide guidance in the engineering design of UTSG.

scholarly journals A Highly D‑efficient Spring Balance Weighing Design for an Even Number of Objects

2019 ◽  
Vol 5 (344) ◽  
pp. 17-27
Author(s):  
Małgorzata Graczyk ◽  
Bronisław Ceranka
Keyword(s):  
Optimal Design ◽  
Sufficient Conditions ◽  
Optimality Criteria ◽  
Point Of View ◽  
Necessary And Sufficient Conditions ◽  
Optimal Designs ◽  
Efficient Design ◽  
Spring Balance ◽  
Experimental Errors ◽  
Necessary And Sufficient

The problem of determining unknown measurements of objects in the model of spring balance weighing designs is presented. These designs are considered under the assumption that experimental errors are uncorrelated and that they have the same variances. The relations between the parameters of weighing designs are deliberated from the point of view of optimality criteria. In the paper, designs in which the product of the variances of estimators is possibly the smallest one, i.e. D‑optimal designs, are studied. A highly D‑efficient design in classes in which a D‑optimal design does not exist are determined. The necessary and sufficient conditions under which a highly efficient design exists and methods of its construction, along with relevant examples, are introduced.

Design of Optimally Stiff Structures Using Shape Density Function

1999 ◽  
Author(s):  
Ashok V. Kumar ◽  
Aaron Wood
Keyword(s):  
Optimal Design ◽  
Density Function ◽  
Material Properties ◽  
Optimization Techniques ◽  
Optimal Designs ◽  
And Topology

Abstract Optimization techniques for the design of the shape and topology of structures is presented where the geometry is represented using contours of a piece-wise bilinear shape density function. The relation between the material properties and the density function is studied to understand the influence of this relation on the optimal design obtained. Relations that would yield homogeneous and fully dense optimal designs are sought.

Investigation on Multi-Objective Optimal Design of a Two Pass Condenser

2013 ◽  
Author(s):  
Lei Chen ◽  
Chang-qi Yan ◽  
Jian-jun Wang
Keyword(s):  
Flow Rate ◽  
Optimization Design ◽  
Optimization Techniques ◽  
Coolant Flow ◽  
Geometric Constraints ◽  
Coolant Flow Rate ◽  
Coolant Temperature ◽  
Outer Diameter ◽  
Pressurized Water ◽  
Multi Objective

Condenser is one of the key components in nuclear power plant with pressurized water reactor. It is important to control the dimension and weight in the design of condenser through optimization techniques. In this paper, a mathematic model of a two pass condenser is set up for Qinshan I condenser. Some modifications are made based on the original multi-objective algorithm, and the comparison between modified algorithm and the original one is conducted. Furthermore, the multi-objective optimization design of the condenser, taking minimization of the coolant flow-rate and net weight as objectives, is carried out considering thermohydraulic and geometric constraints through hybrid Pareto-sorting multi-objective genetic algorithm (HPSMOGA). The sensitivities of some parameters, which may influence the coolant flow-rate and the net weight of condenser, are also analyzed. The results show that the mathematical model is agreeable for the condenser. it is also shown that the proposed multi-objective optimal method is more effective in searching non-dominated solutions. the sensitivity analysis show that the tube outer diameter, tube pitch, coolant velocity and coolant temperature rising influence the coolant flow-rate and net weight of the condenser more than other variables. The corresponding results would provide guidance in the engineering design of this type of condenser.

Economic Evaluation of Maintenance Strategies for Steam Generator Tubes Using Probabilistic Fracture Mechanics and a Financial Method

2007 ◽  
Vol 120 ◽  
pp. 119-126
Author(s):  
Yoshihiro Isobe ◽  
Mitsuyuki Sagisaka ◽  
Shinobu Yoshimura ◽  
Genki Yagawa
Keyword(s):  
Fracture Mechanics ◽  
Steam Generator ◽  
Net Present Value ◽  
Point Of View ◽  
Discounted Cash Flow ◽  
Pressurized Water ◽  
Economic Point ◽  
Probabilistic Fracture Mechanics ◽  
Water Reactors ◽  
Financial Indices

As an application of probabilistic fracture mechanics (PFM) and a financial method, a risk-benefit model was developed for the purpose of optimizing maintenance activities of steam generator (SG) tubes used in pressurized water reactors (PWRs). To justify whether or not it is worth while implementing the selected maintenance strategy in terms of an economic point of view, net present value (NPV) was calculated as an index which is one of the most fundamental financial indices for decision-making based on the discounted cash flow (DCF) method.

Q-optimal experimental designs and close to them experimental designs for polynomial regression on the interval

2020 ◽  
Vol 86 (5) ◽  
pp. 65-72
Author(s):  
Yu. D. Grigoriev
Keyword(s):  
Optimal Design ◽  
Polynomial Regression ◽  
Direct Consequence ◽  
Experimental Designs ◽  
Optimal Designs ◽  
Software Systems ◽  
General Character ◽  
Support Points ◽  
Optimal Weights ◽  
Universal Expression

The problem of constructing Q-optimal experimental designs for polynomial regression on the interval [–1, 1] is considered. It is shown that well-known Malyutov – Fedorov designs using D-optimal designs (so-called Legendre spectrum) are other than Q-optimal designs. This statement is a direct consequence of Shabados remark which disproved the Erdős hypothesis that the spectrum (support points) of saturated D-optimal designs for polynomial regression on a segment appeared to be support points of saturated Q-optimal designs. We present a saturated exact Q-optimal design for polynomial regression with s = 3 which proves the Shabados notion and then extend this statement to approximate designs. It is shown that when s = 3, 4 the Malyutov – Fedorov theorem on approximate Q-optimal design is also incorrect, though it still stands for s = 1, 2. The Malyutov – Fedorov designs with Legendre spectrum are considered from the standpoint of their proximity to Q-optimal designs. Case studies revealed that they are close enough for small degrees s of polynomial regression. A universal expression for Q-optimal distribution of the weights pi for support points xi for an arbitrary spectrum is derived. The expression is used to tabulate the distribution of weights for Malyutov – Fedorov designs at s = 3, ..., 6. The general character of the obtained expression is noted for Q-optimal weights with A-optimal weight distribution (Pukelsheim distribution) for the same problem statement. In conclusion a brief recommendation on the numerical construction of Q-optimal designs is given. It is noted that in this case in addition to conventional numerical methods some software systems of symbolic computations using methods of resultants and elimination theory can be successfully applied. The examples of Q-optimal designs considered in the paper are constructed using precisely these methods.

scholarly journals A Survey on Microgrid Energy Management Considering Flexible Energy Sources

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2156 ◽  
Author(s):  
Hossein Shayeghi ◽  
Elnaz Shahryari ◽  
Mohammad Moradzadeh ◽  
Pierluigi Siano
Keyword(s):  
Energy Management ◽  
Renewable Energy Sources ◽  
Uncertainty Modeling ◽  
Optimization Techniques ◽  
Point Of View ◽  
Energy Sources ◽  
Market Prices ◽  
Distributed Generations ◽  
Peak Loads ◽  
Microgrid Energy Management

Aggregation of distributed generations (DGs) along with energy storage systems (ESSs) and controllable loads near power consumers has led to the concept of microgrids. However, the uncertain nature of renewable energy sources such as wind and photovoltaic generations, market prices and loads has led to difficulties in ensuring power quality and in balancing generation and consumption. To tackle these problems, microgrids should be managed by an energy management system (EMS) that facilitates the minimization of operational costs, emissions and peak loads while satisfying the microgrid technical constraints. Over the past years, microgrids’ EMS have been studied from different perspectives and have recently attracted considerable attention of researchers. To this end, in this paper a classification and a survey of EMSs has been carried out from a new point of view. EMSs have been classified into four categories based on the kind of the reserve system being used, including non-renewable, ESS, demand-side management (DSM) and hybrid systems. Moreover, using recent literature, EMSs have been reviewed in terms of uncertainty modeling techniques, objective functions (OFs) and constraints, optimization techniques, and simulation and experimental results presented in the literature.

A Dynamic Service Pool Size Configuration Mechanism for Service-Oriented Workflow

2011 ◽  
Vol 186 ◽  
pp. 499-504 ◽  
Author(s):  
Pan He ◽  
Jie Xu ◽  
Kai Gui Wu ◽  
Jun Hao Wen
Keyword(s):  
System Reliability ◽  
Environmental Changes ◽  
Point Of View ◽  
Pool Size ◽  
Reliability Model ◽  
Optimal Method ◽  
Service Oriented ◽  
Overall Reliability

Service-oriented workflows are the fundamental structures in service-oriented applications and changes in the workflow could cause dramatic changes in system reliability. In several ways to re-heal workflows in execution, re-sizing service pools in the workflow is practical and easy to implement. In order to quickly adjust to workflow or environmental changes, this paper presents a dynamic service pool size configuration mechanism from the point of view of maintaining workflow reliability. An architecture-based reliability model is used to evaluate the overall reliability of a workflow with service pools and an optimal method is proposed to get the combination of service pool size aiming at minimizing the sum of service pool size subject to the workflow reliability requirement. A case study is used to explain this method and experiment results show how to change service pool size to meet the workflow reliability requirements.

Structural Analysis and Optimal Design of Lightweight Skate for Loading and Unloading

2013 ◽  
Vol 785-786 ◽  
pp. 1258-1261
Author(s):  
In Pyo Cha ◽  
Hee Jae Shin ◽  
Neung Gu Lee ◽  
Lee Ku Kwac ◽  
Hong Gun Kim
Keyword(s):  
Topology Optimization ◽  
Structural Analysis ◽  
Optimal Design ◽  
Optimization Techniques ◽  
Normal Operation ◽  
Stress And Strain ◽  
Initial Model ◽  
Design Variables ◽  
Model Set ◽  
Main Frame

Topology optimization and shape optimization of structural optimization techniques are applied to transport skate the lightweight. Skate properties by varying the design variables and minimize the maximum stress and strain in the normal operation, while reducing the volume of the objective function of optimal design and Skate the static strength of the constraints that should not degrade compared to the performance of the initial model. The skates were used in this study consists of the main frame, sub frame, roll, pin main frame only structural analysis and optimal design was performed using the finite element method. Simplified initial model set design area and it compared to SM45C, AA7075, CFRP, GFRP was using the topology optimization. Strength does not degrade compared to the initial model, decreased volume while minimizing the stress and strain results, the optimum design was achieved efficient lightweight.

The Potential of The Hotel Industry In Pandemic Era Based On Finance Performance Point Of View, Case Study: Indonesia

2021 ◽  
Vol 1 (1) ◽  
pp. 111-123
Author(s):  
Anton Effendi ◽  
◽  
Bambang Hadi Prabowo
Keyword(s):  
Hospitality Industry ◽  
Stock Exchange ◽  
Hotel Industry ◽  
Secondary Data ◽  
Reliable Data ◽  
Point Of View ◽  
Threshold Autoregressive ◽  
Performance Point ◽  
Occupancy Rates

This article aims to investigate and analyze the potential of the hospitality industry by comparing the potential occupancy rates and hotel revenues of foreign and domestic tourists. This investigation uses an investigation of company data obtained from reports from hotel companies throughout Indonesia which are listed on the Indonesia Stock Exchange and secondary data obtained from world banks and other reliable data. This study uses behavioral data analysis using Threshold Autoregressive from 2000 to 2019. It was found that domestic tourists are a new hope that needs to be considered in surviving and restoring the hospitality industry after being exposed to the COVID-19 pandemic which has led hotel companies. temporarily closed operations and part of the hotel went bankrupt. Optimization of domestic tourists allowed the hotel industry to develop rapidly after the Covid-19 pandemic ended.

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