Development Of High-fidelity Simulators Research Articles

Comprehensive framework for data-driven model form discovery of the closure laws in thermal-hydraulics codes

The two-phase two-fluid model is a basis of many thermal-hydraulics codes used in design, licensing, and safety considerations of nuclear power plants. Thermal-hydraulics codes rely on the closure laws to close the system of conservation equations and describe the interactions between phases. These laws, derived from years of experimental investigations, are semi-empirical correlations that lack generality and have a limited range of applicability. Increase of computational power, availability of new experiments, and development of high-fidelity simulations has increased the number of validation data. The discrepancies between the code predictions and the validation data are a great source of knowledge. Missing physics that are not included in the model but are important for the considered phenomena can be discovered by propagating the information from the experimental results through the model. Physics-discovered data-driven model form (P3DM) methodology integrates available integral effect tests and separate effects tests to determine the necessary corrections to the model form of the closure laws. In contrast to existing calibration techniques, the methodology modifies the functional form of the closure laws. Based on the functional form of the correction, the missing physics that were not included in the original model can be discovered. The methodology provides the alternative to the machine learning approach, in which the model is discovered in the form of the intractable black-box relation. In this work, the methodology was applied to the CTF subchannel code to improve the prediction of the two-phase flow phenomena.

Transient reacting flow simulation of spouted fluidized bed for coal-direct chemical looping combustion with different Fe-based oxygen carriers

Coal-direct chemical-looping combustion (CD-CLC) is a next generation combustion technology that shows great promise as a solution for the need of high-efficiency low-cost carbon capture from fossil fueled power plants. To realize this technology on an industrial scale, the development of high-fidelity simulations is a necessary step to develop a thorough understanding of the CLC process. In this paper, simulations of multiphase flow in a CD-CLC process with chemical reactions are performed using the ANSYS Fluent CFD software. Discrete Element Method (DEM) provides the means for tracking the motion of individual metal oxide particles in the CD-CLC system as they react with the fuel and combine with CFD for capturing the solid–gas multiphase hydrodynamics. The overall results of the coupled CFD/DEM simulations using Fe-based oxygen carriers reacting with gaseous CH4 demonstrate that chemical reactions have been successfully incorporated into the CFD/DEM approach. The simulations show a strong dependence of the fluidization performance of the fuel reactor on the density of bed material and provide important insight into selection of a right oxygen carrier for the enhanced performance. This work provides the foundation for future simulations of CD-CLC systems using solid coal as fuel, which will be crucial for successful deployment of CD-CLC technology from the laboratory scale to pilot and industrial scale projects.

Transient Reacting Flow Simulation of Spouted Fluidized Bed for Coal-Direct Chemical Looping Combustion

Coal-direct chemical-looping combustion (CD-CLC) is a next generation combustion technology that shows great promise as a solution for the need of high-efficiency low-cost carbon capture from fossil fueled power plants. To realize this technology on an industrial scale, the development of high-fidelity simulations is a necessary step to develop a thorough understanding of the CLC process. In this paper, simulations for multiphase flow of the CD-CLC process with chemical reactions are performed using ANSYS Fluent computational fluid dynamics (CFD) software. The details of the solid–gas two-phase hydrodynamics in the CLC process are investigated using the Lagrangian particle-tracking approach called the discrete element method (DEM) for the movement and interaction of the solid oxygen carrier particles with the gaseous fuel. The initial CFD/DEM simulation shows excellent agreement with the experimental results obtained in a laboratory scale fuel reactor in cold-flow conditions at Darmstadt University of Technology. Subsequent simulations using 60% Fe2O3 supported on MgAl2O4 reacting with gaseous CH4 demonstrate successful integration of chemical reactions into the CFCD/DEM approach. This work provides a strong foundation for future simulations of CD-CLC systems using solid coal as fuel, which will be crucial for successful deployment of CD-CLC technology from the laboratory scale to pilot and industrial scale projects.

High fidelity simulation in Spain: From dreams to reality

Clinical simulation has emerged as a powerful new tool for the learning and assessment of different skills and attitudes in patient care, by using innovative technology such as high fidelity simulators (HFS). ObjectiveTo describe the current state of high fidelity clinical simulation in Spain and its principal characteristics. MethodsDescriptive observational study that analyzes information on the clinical centres that have HFS in our country. ResultsThere are currently a total of 80 centres with HFS in our country, mainly distributed in university centres (43), hospital and emergency centres (27), simulation centres and institutes of simulation (5), and the rest (5) associated to entities of diverse ownership. The temporal development of HFS has been slowly progressive, with a significant growth in the last 6 years. The majority (74%) have specific facilities, auxiliary equipment (60%), and professionals with a shared commitment (80%). It is already integrated into the training programmes in 56% of university centres with HFS. ConclusionsThe development of HFS has been remarkable in our country, and is mainly related to university undergraduate and postgraduate clinical medical education. It would be useful to design a network of simulation training centres of Health Sciences in Spain, which would be operational, sustainable and recognised, to optimise the use of these facilities.

Simulación de alta fidelidad en España: de la ensoñación a la realidad

Clinical simulation has emerged as a powerful new tool for the learning and assessment of different skills and attitudes in patient care, by using innovative technology such as high fidelity simulators (HFS). ObjectiveTo describe the current state of high fidelity clinical simulation in Spain and its principal characteristics. MethodsDescriptive observational study that analyzes information on the clinical centers that have HFS in our country. ResultsThere are currently a total of 80 centers with HFS in our country, mainly distributed in university centers (43), hospital and emergency centers (27), simulation centers and institutes of simulation (5), and the rest (5) associated to entities of diverse ownership. The temporal development of HFS has been slowly progressive, with a significant growth in the last 6 years. The majority (74%) have specific facilities, auxiliary equipment (60%), and professionals with a shared commitment (80%). It is already integrated into the training programs in 56% of university centers with HFS. ConclusionsThe development of HFS has been remarkable in our country, and is mainly related to university undergraduate and postgraduate clinical medical education. It would be useful to design a network of simulation training centers of Health Sciences in Spain, which would be operational, sustainable and recognized, to optimize the use of these facilities.

‘Appearing the team’: from practice to simulation

Background: The growing trend in the development of high fidelity simulation within undergraduate health care education has produced a range of frameworks and guidelines to structure learning opportunities offered through simulation. An attempt to articulate the process of learning through simulation based on clinical practice experience would appear to be a useful step in the development of simulation-practice links in the provision of further options to facilitate students' learning and continuing professional development. Content: The experience of team identity and integration for undergraduate health care students (n=16, adult nursing, physiotherapy, radiography) undertaking their first critical care practice placement is explored and used to underpin a reflective model to inform learning opportunities offered through high fidelity simulation. The analysis of human interaction offered by Erving Goffman through the use of dramaturgical metaphor is applied to frame the key emergent themes of the critical care experience—'observation', fitting in’, and ‘making a difference’—and shape the developing reflective model. Conclusions: Within the proposed model, the importance of ‘space for reflection’ and ‘meaningful dialogue’ within the context, participation, accessibility, and credibility (CPAC) schema are critical aspects that facilitate the integration and development of confidence in task/technical and interpersonal competencies supporting effective clinical outcome.

Surgical Education in the Internet Era

Technological advancements, along with economic and political issues, have resulted in major changes in surgical education. The development of high fidelity simulators and the widespread availability of the Internet have allowed learning to be shifted away from the operating room. Furthermore, the Internet provides an opportunity for surgical educators to standardize general surgery training and assessment and to develop collaborations nationally and globally. This paper highlights presentations about the challenges as well as the rewards of surgical education in the age of the Internet from the 2009 Academic Surgical Congress.

The importance of organ geometry and boundary constraints for planning of medical interventions

Realistic modeling of medical interventions involving tool–tissue interactions has been considered to be a key requirement in the development of high-fidelity simulators and planners. Organ geometry, soft-tissue constitutive laws, and boundary conditions imposed by the connective tissues surrounding the organ are some of the factors that govern the accuracy of medical intervention planning. In this study it is demonstrated that, for needle path planning, the organ geometry and boundary constraints surrounding the organ are the most important factors influencing the deformation. As an example, the procedure of needle insertion into the prostate (e.g. for biopsy or brachytherapy) is considered. Image segmentation is used to extract the anatomical details from magnetic resonance images, while object-oriented finite element analysis (OOF) software is used to generate finite element (FE) meshes from the segmented images. Two-dimensional FE simulations that account for complex anatomical details along with relative motion between the prostate and its surrounding structure using cohesive zone models are compared with traditional simulation models having simple organ geometry and boundary constraints. Nodal displacements for these simpler models were observed to be up to 14 times larger than those obtained from the anatomically accurate models.

Development of High Fidelity Simulations for Exploring Surgical Stress

Development of High Fidelity Simulations for Exploring Surgical Stress