scholarly journals Model Development and Transient Analysis of the WCLL BB BOP DEMO Configuration Using the Apros System Code

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5593
Author(s):  
Marton Szogradi ◽  
Sixten Norrman
Keyword(s):  
Transient Analysis ◽  
Model Development ◽  
Research Centre ◽  
Primary System ◽  
Balance Of Plant ◽  
Control Scheme ◽  
Analytical Work ◽  
Dynamic Analyses ◽  
Cad Models ◽  
Main Components

Extensive modelling and analytical work has been carried out considering the water-cooled lithium–lead breeding blanket (WCLL BB) balance of plant (BOP) configuration of the demonstration power plant (DEMO) using the Apros system code, developed by VTT Technical Research Centre of Finland Ltd. and Fortum. Contributing to the BOP work package of the EUROfusion Consortium, the integral plant model for dynamic analyses of the WCLL BB configuration has been updated with special attention to primary system components. Following trends of relevant neutronics modelling, a new BB model has been implemented in 2020 with the aim to obtain higher resolution output data and a more realistic thermalhydraulic feedback from the primary system. Once-through steam generator user components have been built based on CAD models conceived by BOP partners. Transient analyses have been performed providing a better picture regarding the behaviour of main components, e.g., the BB and the OTSGs, whilst highlighting possible ways to optimise the control scheme of the plant.

scholarly journals Model Development and Transient Analysis of the HCPB BB BOP DEMO Configuration Using the Apros System Code

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7214
Author(s):  
Marton Szogradi ◽  
Sixten Norrman
Keyword(s):  
Steam Generator ◽  
Storage System ◽  
Model Development ◽  
Energy Storage System ◽  
Research Centre ◽  
Secondary System ◽  
Balance Of Plant ◽  
Analytical Work ◽  
Plant Configuration ◽  
System Coupling

Extensive modeling and analytical work has been carried out considering the Helium-Cooled Pebble Bed Breeding Blanket (HCPB BB) Balance Of Plant (BOP) configuration of the Demonstration Power Plant (DEMO) using the Apros system code, developed by VTT Technical Research Centre of Finland Ltd. and Fortum. The integral plant model of the HCPB BB plant has been improved with respect to the blanket and steam generator models. Based on HCPB-BL2017 v1 data, reported in 2019, the blanket has been remodeled by separate Apros process components, dedicated to average inboard and outboard segments, where the power deposition scheme of the breeding units took into account the output of high-fidelity neutronic analyses. A new helical coil steam generator model has been developed for primary–secondary system coupling using CAD data provided by EUROfusion partner University of Palermo. Transient analyses have been performed with Apros on the plant configuration that utilizes a molten salt technology-based small Energy Storage System (ESS).

scholarly journals Conceptualising changes to tobacco and alcohol policy as affecting a single interlinked system

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Duncan Gillespie ◽  
Jenny Hatchard ◽  
Hazel Squires ◽  
Anna Gilmore ◽  
Alan Brennan
Keyword(s):  
Health Economic ◽  
Policy Change ◽  
Conceptual Understanding ◽  
Communicable Disease ◽  
Model Development ◽  
Economic Models ◽  
Alcohol Policy ◽  
Policy System ◽  
The People ◽  
Main Components

Abstract Background To support a move towards a coordinated non-communicable disease approach in public health policy, it is important to conceptualise changes to policy on tobacco and alcohol as affecting a single interlinked system. For health economic models to effectively inform policy, the first step in their development should be to develop a conceptual understanding of the system complexity that is likely to affect the outcomes of policy change. Our aim in this study was to support the development and interpretation of health economic models of the effects of changes to tobacco and alcohol policies by developing a conceptual understanding of the main components and mechanisms in the system that links policy change to outcomes. Methods Our study was based on a workshop from which we captured data on participant discussions on the joint tobacco–alcohol policy system. To inform these discussions, we prepared with a literature review and a survey of participants. Participants were academics and policy professionals who work in the United Kingdom. Data were analysed thematically to produce a description of the main components and mechanisms within the system. Results Of the people invited, 24 completed the survey (18 academic, 6 policy); 21 attended the workshop (16 academic, 5 policy). Our analysis identified eleven mechanisms through which individuals might modify the effects of a policy change, which include mechanisms that might lead to linked effects of policy change on tobacco and alcohol consumption. We identified ten mechanisms by which the tobacco and alcohol industries might modify the effects of policy changes, grouped into two categories: Reducing policy effectiveness; Enacting counter-measures. Finally, we identified eighteen research questions that indicate potential avenues for further work to understand the potential outcomes of policy change. Conclusions Model development should carefully consider the ways in which individuals and the tobacco and alcohol industries might modify the effects of policy change, and the extent to which this results in an unequal societal distribution of outcomes. Modelled evidence should then be interpreted in the light of the conceptual understanding of the system that the modelling necessarily simplifies in order to predict the outcomes of policy change.

Model development and control of an auto-refrigerated polystyrene polymerization reactor

2021 ◽  
pp. 014233122110251
Author(s):  
Reyhane Mokhtarname ◽  
Ali Akbar Safavi ◽  
Leonhard Urbas ◽  
Fabienne Salimi ◽  
Mohammad M Zerafat ◽  
...  
Keyword(s):  
Temperature Control ◽  
Model Development ◽  
Heat Removal ◽  
Superior Performance ◽  
Polymerization Process ◽  
Vacuum System ◽  
Control Scheme ◽  
Simulation Results ◽  
And Control ◽  
Operating Plant

Dynamic model development and control of an existing operating industrial continuous bulk free radical styrene polymerization process are carried out to evaluate the performance of auto-refrigerated CSTRs (continuous stirred tank reactors). One of the most difficult tasks in polymerization processes is to control the high viscosity reactor contents and heat removal. In this study, temperature control of an auto-refrigerated CSTR is carried out using an alternative control scheme which makes use of a vacuum system connected to the condenser and has not been addressed in the literature (i.e. to the best of our knowledge). The developed model is then verified using some experimental data of the real operating plant. To show the heat removal potential of this control scheme, a common control strategy used in some previous studies is also simulated. Simulation results show a faster dynamics and superior performance of the first control scheme which is already implemented in our operating plant. Besides, a nonlinear model predictive control (NMPC) is developed for the polymerization process under study to provide a better temperature control while satisfying the input/output and the heat exchanger capacity constraints on the heat removal. Then, a comparison has been also made with the conventional proportional-integral (PI) controller utilizing some common tuning rules. Some robustness and stability analyses of the control schemes investigated are also provided through some simulations. Simulation results clearly show the superiority of the NMPC strategy from all aspects.

Cutting Tool Temperatures in Contour Turning: Transient Analysis and Experimental Verification

1997 ◽  
Vol 119 (4A) ◽  
pp. 494-501 ◽  
Author(s):  
D. A. Stephenson ◽  
T.-C. Jen ◽  
A. S. Lavine
Keyword(s):  
Transient Analysis ◽  
Cutting Tool ◽  
Process Development ◽  
Thermal Contact ◽  
Model Development ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Transient Conditions ◽  
Trouble Shooting ◽  
Model Predictions

This paper describes a model for predicting cutting tool temperatures under transient conditions. It is applicable to processes such as contour turning, in which the cutting speed, feed rate, and depth of cut may vary continuously with time. The model is intended for use in process development and trouble shooting. Therefore, emphasis is given in the model development to enable rapid computation and to avoid the need to specify parameters such as thermal contact resistances and convection coefficients which are not known in practice. Experiments were conducted to validate the predictive model. The model predictions with two different boundary conditions bound the experimental results. An example is presented which shows the utility of the model for process planning.

Dynamic Model Development of Linear Fresnel Solar Field

2015 ◽  
Author(s):  
Elina Hakkarainen ◽  
Matti Tähtinen ◽  
Hannu Mikkonen
Keyword(s):  
Control System ◽  
Dynamic Simulation ◽  
Model Development ◽  
Control Mode ◽  
Plant Behavior ◽  
Clear Sky ◽  
Control Scheme ◽  
Control Schemes ◽  
And Control ◽  
Solar Field

As a dispatchable clean energy source, concentrated solar power (CSP) can be one of the key technologies to overcome many problems related to fossil fuel consumption and electricity balancing problems. Solar is a variable location, time and weather dependent source of energy, which sets challenges to solar field operations. With proper dynamic simulation tools it is possible to study dynamics of CSP field under changing weather conditions, find optimum control strategies, and plan and predict the performance of the field. CSP technology considered in this paper, linear Fresnel reflector (LFR), is a proven line focusing technology, having simpler design but suffering in optical performance compared to more mature parabolic trough (PT) technology. Apros dynamic simulation software is used to configure and simulate the solar field. Apros offers a possibility to dynamically simulate field behavior with varying collector configuration, field layout and control mode under varying irradiation conditions. The solar field applies recirculation (RC) as a control mode and direct steam generation (DSG) producing superheated steam. DSG sets challenges for the control scheme, which main objective is to maintain constant steam pressure and temperature at the solar field outlet under varying inlet water and energy conditions, while the steam mass flow can vary. The design and formulation of an entire linear Fresnel solar field in Apros is presented, as well as the obtained control scheme. The field includes user defined amount of collector modules, control system and two modules describing solar irradiation on the field. As two-phase water/steam flow is used, an accurate 6-equation model is used in Apros. Irradiation on the solar field under clear sky conditions is calculated according to time, position and Linke turbidity factor. Overcast conditions can be created by the clear sky index. For LFR single-axis sun tracking system is applied. In order to test the model functionality and to investigate the field behavior, thermal performance of the field was simulated at different dates at two different locations, and the results were compared. Similar field dimensions and control schemes were applied in each case, and simulations were done for full 24 hours in order to study the daily operations and ensure process stability. Control scheme functionality is evaluated based on the plant behavior in simulation cases having different operational conditions. The proper operability of the configured LFR model is evaluated. Obtained performance results show differences between locations and variation depending on season and time. The importance of a proper control system is revealed. The results show that the dynamic model development of a solar field is necessary in order to simulate plant behavior under varying irradiation conditions and to further develop optimal field control schemes and field optimizing process. The future work in the development of the LFR model presented will focus on dynamic response behavior development under transient conditions and field start-up and shut down procedure development.

Development and Preliminary Validation of a STH-CFD Coupling Method for Multiscale Thermal-Hydraulic Simulations of the MYRRHA Reactor

2016 ◽  
Author(s):  
A. Toti ◽  
J. Vierendeels ◽  
F. Belloni
Keyword(s):  
Research Reactor ◽  
Fluid Dynamic ◽  
Domain Decomposition Method ◽  
Test Facility ◽  
Research Centre ◽  
High Tech ◽  
Primary System ◽  
Complex Flow ◽  
Transient Event ◽  
Flow Mixing

MYRRHA (Multi-purpose hybrid research reactor for high-tech applications) is a lead-bismuth eutectic (LBE) cooled research reactor currently under development at SCK•CEN, the Belgian Nuclear Research Centre. The compact design of the pool-type primary system implies the presence of pronounced 3D thermal fluid-dynamic phenomena, which can affect the evolution of certain accidental transients such as loss of flow (LOF). System thermal-hydraulics (STH) codes, conceived to carry out global NPP safety analyses, present severe limitations in taking into account local 3D phenomena including flow mixing, thermal stratification, etc. To overcome this limitation, a promising solution is coupling STH codes with CFD codes, which can calculate complex flow fields but result, on the other hand, in too expensive computational resources for whole-plant simulations. A domain decomposition method that couples the STH code RELAP5-3D and the CFD code Ansys FLUENT has been developed and implemented. Proof-of-principle tests on simple configurations have been carried out to demonstrate its validity and to identify modeling and numerical issues. The experimental campaign carried out at the test facility TALL-3D, operated by the KTH Royal Institute of Technology in Sweden, has been selected for preliminary verification and validation (V&V) of this method. This paper presents the results of the coupled 1D-3D simulation of a forced-to-natural circulation transient event, whose evolution results to be strongly affected by flow mixing and stratification phenomena. The experimental validation, based on a high-quality set of experimental data, is currently on-going. Further development and validation activities will be carried out in the experimental facility ESCAPE, under commissioning at SCK•CEN, within the recently launched EU project MYRTE (Horizon 2020 programme).

Advanced Composite Turboprops: Modeling, Structural, and Dynamic Analyses

1988 ◽  
Vol 110 (2) ◽  
pp. 306-311 ◽  
Author(s):  
R. A. Aiello ◽  
S. Chi
Keyword(s):  
Wind Tunnel ◽  
High Performance ◽  
Model Development ◽  
Computer Code ◽  
Mode Shapes ◽  
Composite Blade ◽  
Advanced Composite ◽  
Tunnel Model ◽  
Dynamic Analyses ◽  
Fan Blade

This paper presents a structural and dynamic analysis of a scaled-down wind tunnel model prop-fan blade made from fiber composites. This blade is one of a series of prop-fan blades that have been tested at the Lewis Research Center wind tunnel facilities. The blade is highly swept and twisted and of the spar/shell construction. Due to the complexity of the blade geometry and its high performance, it is subjected to much higher loads and tends to be much less stable than conventional blades. The structural and dynamic analyses of the blade were performed using the NASA-Lewis COBSTRAN computer code. COBSTRAN is designed to generate the mesh and calculate the anisotropic material properties for composite blade analysis. Comparison of analytical and experimental mode shapes and frequencies are shown, verifying the model development and analysis techniques used. The methodologies and programs developed for this analysis are directly applicable to other prop-fan blades.

Decision Support System for Sanitary Teams Activities

2014 ◽  
Vol 6 (3) ◽  
pp. 65-87 ◽  
Author(s):  
Radosław Pytlak ◽  
Wojciech Stecz ◽  
Damian Suski ◽  
Tomasz Zawadzki
Keyword(s):  
Optimal Control ◽  
Information System ◽  
Model Calibration ◽  
Optimal Control Problems ◽  
Actual Data ◽  
Control Problems ◽  
Epidemic Outbreak ◽  
Analytical Work ◽  
Complex Models ◽  
Main Components

This paper describes the information system that has been built for the support of sanitary teams. The system is aimed at supporting analytical work which must be carried out when there is a risk of an epidemic outbreak. It is meant to provide tools for predicting the size of an epidemic on the basis of the actual data collected during its course. Since sanitary teams try to control the size of the epidemics such a tool must model also sanitary teams activities. As a result a model for the prediction can be quite complicated in terms of the number of equations it contains. Furthermore, since a model is based on several parameters there must be a tool for finding these parameters on the basis on the actual data corresponding to the epidemic evolution. The paper describes the proposition of such a system. It presents, in some details, the main components of the system. In particular, the environment for building complex models (containing not only the epidemic model but also activities of sanitary teams trying to inhibit the epidemic) is discussed. Then, the module for a model calibration is presented. The module is a part of server for solving optimal control problems and can be accessed via Internet. Finally, this paper shows how optimal control problems can be constructed with the aim of the efficient epidemic management. Some optimal control problems related to that issue are discussed and numerical results of its solution are presented.

Sign in / Sign up

Export Citation Format

Share Document