Narrow-angle radiometers based on the International Flame Research Foundation design have been us... more Narrow-angle radiometers based on the International Flame Research Foundation design have been used to measure the incident radiative heat flux in a coal-fired combustion furnace located at the University of Utah. This method of heat flux measurement uses a probe that limits the field of view, allowing radiation measurements of relatively precise locations. The probe contains a Wheatstone bridge with two thermistors, one that is irradiated and one that is not. The measured voltage difference between the two thermistors is used to determine the heat flux based on calibration curves obtained in a blackbody furnace. This calibration produces a curve of measured voltage vs. blackbody temperature. The heat flux is calculated from the blackbody temperature and corrected for the view angle. Using the concept of an instrument model, we have conducted an extensive analysis of the errors associated with using this radiometer design to measure incident heat flux. The purpose of an instrument m...
The work described in this paper is part of the larger mission of the Carbon-Capture Multidiscipl... more The work described in this paper is part of the larger mission of the Carbon-Capture Multidisciplinary Simulation Center (CCMSC) (http://ccmsc.utah.edu) at the University of Utah. The purpose of this center is to demonstrate the use of exascale computing with verification and validation/uncertainty quantification (V&VUQ) as a means of accelerating deployment of advanced, low cost, low emission coal-fired power generation technologies. This paper focuses on measurement techniques and the supporting instrument model developments used to determine wall temperature, radiation and heat flux during oxy-combustion experiments in the 1.5 MWth L1500 pulverized coal furnace located at University of Utah’s Industrial Combustion and Gasification Research Facility.
Heat Transfer: Volume 4 — Combustion and Energy Systems, 2001
In a large-scale pool fire simulation, the processes that must be modeled are complex and coupled... more In a large-scale pool fire simulation, the processes that must be modeled are complex and coupled. The flow is often highly turbulent, dynamic vortical structures are present, the chemical reactions involve several thousand elementary steps and hundreds of species/intermediates, and radiation, the dominant mode of heat transfer, is strongly affected by the presence of soot. The range of length and time scales associated with all these processes cannot be simulated on even the most powerful supercomputers available today. Our approach to making this intractable problem tractable has been twofold: one, to improve the models used at all levels in the simulation (i.e., transport models and subgrid scale models) and two, to parallelize the simulation tool to run on massively parallel machines. We have employed Large Eddy Simulation (LES) to model the fluid dynamics and the convection-diffusion scalar transport. LES successfully captures the transient nature of the coherent vortical struc...
Journal of Verification, Validation and Uncertainty Quantification, 2021
We apply Bayesian inference to instrument calibration and experimental-data uncertainty analysis ... more We apply Bayesian inference to instrument calibration and experimental-data uncertainty analysis for the specific application of measuring radiative intensity with a narrow-angle radiometer. We develop a physics-based instrument model that describes temporally varying radiative intensity, the indirectly measured quantity of interest, as a function of scenario and model parameters. We identify a set of five uncertain parameters, find their probability distributions (the posterior or inverse problem) given the calibration data by applying Bayes' Theorem, and employ a local linearization to marginalize the nuisance parameters resulting from errors-in-variables. We then apply the instrument model to a new scenario that is the intended use of the instrument, a 1.5 MW coal-fired furnace. Unlike standard error propagation, this Bayesian method infers values for the five uncertain parameters by sampling from the posterior distribution and then computing the intensity with quantifiable u...
Journal of Verification, Validation and Uncertainty Quantification, 2017
Quantification of uncertainty in the simulation results becomes difficult for complex real-world ... more Quantification of uncertainty in the simulation results becomes difficult for complex real-world systems with little or no experimental data. This paper describes a validation and uncertainty quantification (VUQ) approach that integrates computational and experimental data through a range of experimental scales and a hierarchy of complexity levels. This global approach links dissimilar experimental datasets at different scales, in a hierarchy, to reduce quantified error bars on case with sparse data, without running additional experiments. This approach was demonstrated by applying on a real-world problem, greenhouse gas (GHG) emissions from wind tunnel flares. The two-tier validation hierarchy links, a buoyancy-driven helium plume and a wind tunnel flare, to increase the confidence in the estimation of GHG emissions from wind tunnel flares from simulations.
... Subtask 4.4 - Effect of Oil Shale Processing on Water Compositions (PI: Milind Deo) ... kerog... more ... Subtask 4.4 - Effect of Oil Shale Processing on Water Compositions (PI: Milind Deo) ... kerogen pyrolysis, porosity, kerogen/clay structural models) and in the application of simulation tools to in-situ thermal treatment processes (eg pyrolysis/in-situ combustion and rubblized beds). ...
Realistic simulation of complicated systems such as large-scale pool fires requires the represent... more Realistic simulation of complicated systems such as large-scale pool fires requires the representation of relevant physical processes such as turbulent reacting flows, convective and radiative heat transfer, and fundamental gas-phase chemistry. Resolution of the length and time scales responsible for controlling the dynamic features of fire are also required to capture important fire physics. Resolving these length and time scales, however, requires massively parallel computations. To achieve coupling of these complicated processes in a massively parallel environment, software components that reuse physics-based, legacy fire codes (written in Fortran) are developed and integrated with Uintah, a component-based, visual Problem Solving Environment (PSE) [1]. Uintah provides the framework for large-scale parallelization for different applications. The integration of the new fire code in Uintah is built on three principles: 1) Develop different, reusable, physics-based components that c...
Narrow-angle radiometers based on the International Flame Research Foundation design have been us... more Narrow-angle radiometers based on the International Flame Research Foundation design have been used to measure the incident radiative heat flux in a coal-fired combustion furnace located at the University of Utah. This method of heat flux measurement uses a probe that limits the field of view, allowing radiation measurements of relatively precise locations. The probe contains a Wheatstone bridge with two thermistors, one that is irradiated and one that is not. The measured voltage difference between the two thermistors is used to determine the heat flux based on calibration curves obtained in a blackbody furnace. This calibration produces a curve of measured voltage vs. blackbody temperature. The heat flux is calculated from the blackbody temperature and corrected for the view angle. Using the concept of an instrument model, we have conducted an extensive analysis of the errors associated with using this radiometer design to measure incident heat flux. The purpose of an instrument m...
The work described in this paper is part of the larger mission of the Carbon-Capture Multidiscipl... more The work described in this paper is part of the larger mission of the Carbon-Capture Multidisciplinary Simulation Center (CCMSC) (http://ccmsc.utah.edu) at the University of Utah. The purpose of this center is to demonstrate the use of exascale computing with verification and validation/uncertainty quantification (V&VUQ) as a means of accelerating deployment of advanced, low cost, low emission coal-fired power generation technologies. This paper focuses on measurement techniques and the supporting instrument model developments used to determine wall temperature, radiation and heat flux during oxy-combustion experiments in the 1.5 MWth L1500 pulverized coal furnace located at University of Utah’s Industrial Combustion and Gasification Research Facility.
Heat Transfer: Volume 4 — Combustion and Energy Systems, 2001
In a large-scale pool fire simulation, the processes that must be modeled are complex and coupled... more In a large-scale pool fire simulation, the processes that must be modeled are complex and coupled. The flow is often highly turbulent, dynamic vortical structures are present, the chemical reactions involve several thousand elementary steps and hundreds of species/intermediates, and radiation, the dominant mode of heat transfer, is strongly affected by the presence of soot. The range of length and time scales associated with all these processes cannot be simulated on even the most powerful supercomputers available today. Our approach to making this intractable problem tractable has been twofold: one, to improve the models used at all levels in the simulation (i.e., transport models and subgrid scale models) and two, to parallelize the simulation tool to run on massively parallel machines. We have employed Large Eddy Simulation (LES) to model the fluid dynamics and the convection-diffusion scalar transport. LES successfully captures the transient nature of the coherent vortical struc...
Journal of Verification, Validation and Uncertainty Quantification, 2021
We apply Bayesian inference to instrument calibration and experimental-data uncertainty analysis ... more We apply Bayesian inference to instrument calibration and experimental-data uncertainty analysis for the specific application of measuring radiative intensity with a narrow-angle radiometer. We develop a physics-based instrument model that describes temporally varying radiative intensity, the indirectly measured quantity of interest, as a function of scenario and model parameters. We identify a set of five uncertain parameters, find their probability distributions (the posterior or inverse problem) given the calibration data by applying Bayes' Theorem, and employ a local linearization to marginalize the nuisance parameters resulting from errors-in-variables. We then apply the instrument model to a new scenario that is the intended use of the instrument, a 1.5 MW coal-fired furnace. Unlike standard error propagation, this Bayesian method infers values for the five uncertain parameters by sampling from the posterior distribution and then computing the intensity with quantifiable u...
Journal of Verification, Validation and Uncertainty Quantification, 2017
Quantification of uncertainty in the simulation results becomes difficult for complex real-world ... more Quantification of uncertainty in the simulation results becomes difficult for complex real-world systems with little or no experimental data. This paper describes a validation and uncertainty quantification (VUQ) approach that integrates computational and experimental data through a range of experimental scales and a hierarchy of complexity levels. This global approach links dissimilar experimental datasets at different scales, in a hierarchy, to reduce quantified error bars on case with sparse data, without running additional experiments. This approach was demonstrated by applying on a real-world problem, greenhouse gas (GHG) emissions from wind tunnel flares. The two-tier validation hierarchy links, a buoyancy-driven helium plume and a wind tunnel flare, to increase the confidence in the estimation of GHG emissions from wind tunnel flares from simulations.
... Subtask 4.4 - Effect of Oil Shale Processing on Water Compositions (PI: Milind Deo) ... kerog... more ... Subtask 4.4 - Effect of Oil Shale Processing on Water Compositions (PI: Milind Deo) ... kerogen pyrolysis, porosity, kerogen/clay structural models) and in the application of simulation tools to in-situ thermal treatment processes (eg pyrolysis/in-situ combustion and rubblized beds). ...
Realistic simulation of complicated systems such as large-scale pool fires requires the represent... more Realistic simulation of complicated systems such as large-scale pool fires requires the representation of relevant physical processes such as turbulent reacting flows, convective and radiative heat transfer, and fundamental gas-phase chemistry. Resolution of the length and time scales responsible for controlling the dynamic features of fire are also required to capture important fire physics. Resolving these length and time scales, however, requires massively parallel computations. To achieve coupling of these complicated processes in a massively parallel environment, software components that reuse physics-based, legacy fire codes (written in Fortran) are developed and integrated with Uintah, a component-based, visual Problem Solving Environment (PSE) [1]. Uintah provides the framework for large-scale parallelization for different applications. The integration of the new fire code in Uintah is built on three principles: 1) Develop different, reusable, physics-based components that c...
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Papers by Jennifer Spinti