scholarly journals IMPLEMENTATION OF DATA ASSIMILATION METHODOLOGY FOR PHYSICAL MODEL UNCERTAINTY EVALUATION USING POST-CHF EXPERIMENTAL DATA

2014 ◽  
Vol 46 (5) ◽  
pp. 619-632 ◽  
Author(s):  
JAESEOK HEO ◽  
SEUNG-WOOK LEE ◽  
KYUNG DOO KIM
Keyword(s):  
Experimental Data ◽  
Data Assimilation ◽  
Physical Model ◽  
Model Uncertainty ◽  
Uncertainty Evaluation

scholarly journals Data assimilation and uncertainty assessment in 3D geological modeling

2017 ◽  
Author(s):  
Daniel Schweizer ◽  
Philipp Blum ◽  
Christoph Butscher
Keyword(s):  
Data Assimilation ◽  
Information Entropy ◽  
Model Uncertainty ◽  
Model Space ◽  
Distance Measures ◽  
Geological Model ◽  
Multiple Model ◽  
Geological Data ◽  
3D Geological Modeling ◽  
Model Geometry

Abstract. The quality of a 3D geological model strongly depends on the type of integrated geological data, their interpretation and associated uncertainties. In order to improve an existing geological model and effectively plan further site investigation, it is of paramount importance to identify existing uncertainties within the model space. Information entropy, a voxel based measure, provides a method for assessing structural uncertainties, comparing multiple model interpretations and tracking changes across consecutively built models. The aim of this study is to evaluate the effect of data assimilation on model uncertainty, model geometry and overall structural understanding. Several geological 3D models of increasing complexity, incorporating different input data categories, were built for the study site Staufen (Germany). We applied the concept of information entropy in order to visualize and quantify changes in uncertainty between these models. Furthermore, we propose two measures, the Jaccard and the City-Block distance, to directly compare dissimilarities between the models. The study shows that different types of geological data have disparate effects on model uncertainty and model geometry. The presented approach using both information entropy and distance measures can be a major help in the optimization of 3D geological models.

Quantification of the RELAP5 Model Uncertainty for Application to the Loss-of-RHR Event During the Mid-Loop Operation

2009 ◽  
Author(s):  
Ikuo Kinoshita ◽  
Hiroichi Nagumo ◽  
Minoru Yamada ◽  
Yasuhiro Sasaki ◽  
Yoshitaka Yoshida
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Model Uncertainty ◽  
Stratified Flow ◽  
Condensation Heat Transfer ◽  
Analysis Method ◽  
Gas Distribution ◽  
Two Phase ◽  
Model Parameter ◽  
Best Estimate

Best estimate analysis method for the loss of Residual Heat Removal (loss-of-RHR) event during the mid-loop operation is being conducted along the Code Scaling, Applicability and Uncertainty (CSAU) evaluation methodology. The analysis method uses RELAP5/MOD3.2 as a best estimate analysis code. One of the important processes in the CSAU methodology is the development of the Phenomena Identification and Ranking Table (PIRT) which identifies thermal-hydraulic phenomena during the event and ranks the identified phenomena from the view point of influence on the safety evaluation parameters. The safety parameters for evaluation are Reactor Coolant System (RCS) pressure and reactor vessel water level. The PIRT for the reflux cooling of the loss-of-RHR event during the mid-loop operation was developed based on existing integral test results, plant analysis results and related papers considering influence on coolant distribution, non-condensible gas distribution and heat transfer. Referenced integral tests are ROSA-IV/LSTF, BETHSY, PKL and IIST. Uncertainty of RELAP5/MOD3.2 physical models related to high ranked phenomena identified in the PIRT for the reflux cooling is quantified using the related experimental data for application to PWR plant statistical analysis based on the developed verification matrix. Uncertainty quantified models are void model, horizontal stratified flow criteria and SG condensation heat transfer. These models are related to the following phenomena respectively. Void model (interfacial friction factor in bubbly and slug flow regimes): - Two phase expansion in core and upper plenum due to core boiling. - Two phase flow to Steam Generator (SG) inlet plenum and U-tubes. Horizontal stratified flow criterion: - Stratification of flow in hot leg. - Water transportation from hot leg to SG by steam flow. SG condensation heat transfer model: - Heat transfer in SG U-tube under presence of non-condensable gas. Distribution of model parameter multiplier which represents model uncertainty was obtained by either experiment analysis by RELAP5 or comparison of separate RELAP5 model prediction to experimental data. Mean value and standard deviation are calculated for distribution of model parameter multiplier.

Modelling of Electrodynamic Phenomena in Slowly Moving Media

2017 ◽  
Vol 72 (8) ◽  
pp. 757-762 ◽  
Author(s):  
Andrey Leonidovich Rozov
Keyword(s):  
Experimental Data ◽  
Physical Model ◽  
Electromagnetic Fields ◽  
Classical Mechanics ◽  
Previous Article ◽  
Alternative Methods ◽  
Theory Of Relativity ◽  
Relativity Principle ◽  
New Approach ◽  
Moving Media

AbstractWe discuss the feasibility of using, along with Minkowski equations obtained on the basis of the theory of relativity and used at present in electrodynamics, alternative methods of describing the processes of interaction between electromagnetic fields and moving media. In this article, a way of describing electromagnetic fields in terms of classical mechanics is offered. A system of electrodynamic equations for slowly moving media was derived on the basis of Maxwell’s theory within the framework of classical mechanics using Wilsons’ experimental data with dielectrics in a previous article [A. Rozov, Z. Naturforsch. 70, 1019 (2015)]. This article puts forward a physical model that explains the features of the derived equations. The offered model made it possible to suggest a new approach to the derivation of electrodynamic equations for slowly moving media. A variant of Galileo’s relativity principle, in accordance with which the electrodynamic equations for slowly moving media should be considered as Galilean-invariant, is laid down on the basis of both the interpretation of Galileo’s concept following from Galileo’s works and Pauli’s concept of postulate of relativity within the framework of the represented physical model.

Two-stage model of prepreg bonding interface formation in automated fiber placement process

2022 ◽  
pp. 073168442110602
Author(s):  
Rui Xiao ◽  
Wang Wang ◽  
Jiaqi Shi ◽  
Jun Xiao
Keyword(s):  
Experimental Data ◽  
Physical Model ◽  
Failure Mode ◽  
Process Parameters ◽  
Formation Process ◽  
Bonding Interface ◽  
Interface Formation ◽  
Fiber Placement ◽  
Logarithmic Curve ◽  
Automated Fiber Placement

While Automated Fiber Placement (AFP) of thermoset matrix composites are widely used in the aviation industry, there is little conclusive research on the relationship between the physical model of bonding interface formation process and the actual bonding strength between prepreg layers formed in AFP process. Although massive amounts of experimental data on prepreg tack have been achieved from existing research, engineers are unable to use these data as a decisive criterion in choosing process parameters. In this research, a prepreg layup physical model based on reptation model and viscoelastic mechanical model is built, in which the bonding interface formation process is divided into two stages, namely, diffusion and viscous stage. Layup-peeling experiments are conducted via a special designed high-speed layup experimental platform so that practical AFP process parameters can be imitated, and a logarithmic curve of layup velocity-peeling energy under different layup pressure is achieved. The slope of the logarithmic curve and the surface morphology of the sample after peeling prove the correctness of the established model. Simultaneously, the experimental data proves that when prepreg is peeled off, the transition from the cohesive failure mode to the interface failure mode occurs at the laying speed between 100 mm/s and 200 mm/s. These results can be used as a reference for choosing AFP process parameters to realize the balance between good bonding quality and harmless separation of adjacent prepreg layers.

An Experimental Study of Steam-Solvent Coinjection for Bitumen Recovery Using a Large-Scale Physical Model

SPE Journal ◽  
1900 ◽  
pp. 1-18
Author(s):  
Kai Sheng ◽  
Ryosuke Okuno ◽  
Abdullah Al-Gawfi ◽  
Petro Nakutnyy ◽  
Muhammad Imran ◽  
...  
Keyword(s):  
Experimental Data ◽  
Temperature Distribution ◽  
Simulation Model ◽  
Physical Model ◽  
Material Balance ◽  
Cocurrent Flow ◽  
Internal Diameter ◽  
Asphaltene Content ◽  
Bitumen Recovery

Summary In this paper, we present a solvent-assistedsteam-assisted gravity drainage (SA-SAGD) experiment with multicomponent solvent (i.e., condensate) using a large physical model. The sandpack for the experiment had a porosity of 0.33 and a permeability of 5.6 darcies in the cylindrical pressure vessel that was 1.22 m in length and 0.425 m in internal diameter. The sandpack was initially saturated with 93% Athabasca bitumen and 7% deionized water. The main objective of this research was to study the in-situ thermal/compositional flow and produced bitumen properties in SA-SAGD with condensate. After the preheating of the sandpack for 24 hours, SA-SAGD with 2.8-mol% condensate was performed at 50 cm3/min (cold-water equivalent) at 3500 kPa for 3 days. The experimental data of production, injection, and temperature distribution were recorded. Also, 10 samples of produced oil were taken and analyzed for density and asphaltene content. The sandpack was excavated after the experiment to analyze the asphaltene content in the remaining oil at different locations. A numerical simulation model was calibrated based on the data of material balance and temperature distribution, and it was validated with properties of the produced and excavated samples. The simulation model used fluid models based on experimental data of viscosities, densities, and bubblepoints for four condensate/bitumen mixtures. Results showed that SA-SAGD was efficient in bitumen recovery with a cumulative steam-to-oil ratio (SOR) that was two to three times smaller than that in SAGD using the same physical model. Detailed analysis of the calibrated simulation model indicated that SA-SAGD enabled the steam chamber to expand more efficiently with a smaller amount of water throughput than SAGD. Volatile solvent components tended to remain in the chamber, and the condensed solvent components acted as a miscible carrier for bitumen components. The analysis further showed that the more efficient oil recovery in SA-SAGD occurred with predominantly cocurrent flow of oil and water near the chamber edge. SA-SAGD recovered a larger amount of asphaltene components (i.e., less in-situ upgrading) than SAGD likely because of its lower chamber temperature, shorter production period, and enhanced local displacement efficiency.

A Spatially Resolved Physical Model for Dynamic Modeling of a Novel Hybrid Reformer-Electrolyzer-Purifier (REP) for Production of Hydrogen

2017 ◽  
Author(s):  
Derek McVay ◽  
Li Zhao ◽  
Jack Brouwer ◽  
Fred Jahnke ◽  
Matt Lambrech
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Steady State ◽  
Fuel Cell ◽  
Physical Model ◽  
Physical Models ◽  
Co2 Removal ◽  
Molten Carbonate ◽  
Spatially Resolved ◽  
Production Of Hydrogen

A molten carbonate electrolysis cell (MCEC) is capable of separating carbon dioxide from methane reformate while simultaneously electrolyzing water. Methane reformate, for this study, primarily consists of carbon dioxide, hydrogen, methane, and a high percentage of water. Carbon dioxide is required for the operation of a MCEC since a carbonate ion is formed and travels from the reformate channel to the sweep gas channel. In this study, a spatially resolved physical model was developed to simulate an MCEC in a novel hybrid reformer electrolyzer purifier (REP) configuration for high purity hydrogen production from methane and water. REP effectively acts as an electrochemical CO2 purifier of hydrogen. In order to evaluate the performance of REP, a dynamic MCEC stack model was developed based upon previous high temperature molten carbonate fuel cell modeling studies carried out at the National Fuel Cell Research Center at the University of California, Irvine. The current model is capable of capturing both steady state performance and transient behavior of an MCEC stack using established physical models originating from first principals. The model was first verified with REP experimental data at steady state which included spatial temperature profiles. Preliminary results show good agreement with experimental data in terms of spatial distribution of temperature, current density, voltage, and power. The combined effect of steam methane reformation (SMR) and water electrolysis with electrochemical CO2 removal results in 96% dry-basis hydrogen at the cathode outlet of the MCEC. Experimental measurements reported 98% dry-basis hydrogen at the cathode outlet.

scholarly journals The Investigation of the Stability for Multistage Axial Compressors

1985 ◽  
Author(s):  
Diyi Tang ◽  
Wenlan Li ◽  
Mengzi Cong
Keyword(s):  
Experimental Data ◽  
Physical Model ◽  
Axial Compressors ◽  
Volume Model ◽  
Multistage Compressors ◽  
Multistage Compressor ◽  
The Stability

The “actuator-delay-volume” is used as a physical model for stages of compressors instead of “actuator-lumped volume” model to predict the stability of multistage compressors. The stall line of a multistage compressor is predicted with these two models respectively. The results of simulation are compared with the experimental data of a compressor rig. In order to identify the investigation, the tests, in which the engine is forced into stall and supplied with distorted inflow, have been conducted. The investigation shows that the model is well improved by incorporating an “inertia link” into the model between the “actuator” and the “lumped volume”.

Sign in / Sign up

Export Citation Format

Share Document