Publications

Displaying 76 - 91 of 91

Exceptionally reliable density solving algorithms for multiparameter mixture models from Chebyshev expansion rootfinding

May 21, 2018

Author(s)

Ian H. Bell, Bradley K. Alpert

Calculation of the density of a mixture for a given tem- perature, pressure, and mixture composition from multi- parameter mixture models (like the so-called GERG model) sometimes fails; failures are caused by insuffi- ciently accurate estimations of the

Consistent Twu parameters for more than 2300 pure fluids from critically evaluated experimental data

February 26, 2018

Author(s)

Ian H. Bell, Marco Satyro, Eric W. Lemmon

Standard cubic equations of state like Peng-Robinson or SRK do not, by their construction, yield physically reasonable values by default when the equation of state is extrapolated beyond the range where experimental data are available. A multi-property

ChebTools: C++11 (and Python) tools for working with Chebyshev expansions

February 12, 2018

Author(s)

Ian H. Bell, Bradley K. Alpert, Lucas Bouck

NISTfit: A natively multithreaded C++11 framework for model development

February 12, 2018

Author(s)

Ian H. Bell, Matthias Kunick

The current trend in computer architecture is for increasingly parallel computation while the clock frequency stagnates. The increase in computing speed is achieved by dividing a process into several threads which are executed in parallel on multiple

On the construction of binary mixture p-x and T-x diagrams from isochoric thermodynamics

January 24, 2018

Author(s)

Ian H. Bell, Ulrich K. Deiters

In this work we describe how to efficiently and reliably calculate $p$-$x$ and $T$-$x$ diagrams for binary mixtures of fluids. The method is based on the use of the Helmholtz energy density as the fundamental thermodynamic potential. Through the use of

Algorithms for the calculation of psychrometric properties from multi-fluid Helmholtz-energy- explicit models

October 18, 2017

Author(s)

Ian H. Bell, Eric W. Lemmon, Allan H. Harvey

Psychrometric properties of humid air are widely used in the analysis and modeling of thermal systems. In this work, we present a method for obtaining these properties from the multi-fluid mixture formulation of the GERG mixture model. This mixture model

Uncertainty Assessment of Equations of State with Application to an Organic Rankine Cycle

July 2, 2017

Author(s)

Jerome Frutiger, Ian Bell, O'Connell J. P., Kenneth Kroenlein, Jens Abildskov, Gurkan Sin

Evaluations of equations of state (EoS) with application to process systems should include uncertainty analysis. A generic method is presented for determining such uncertainties from both the mathematical form and the data for obtaining EoS parameter

Calculation of critical points from Helmholtz-energy-explicit mixture models

February 15, 2017

Author(s)

Ian H. Bell, Andreas Jaeger

Uncertainty Assessment of Equations of State Applied to Organic Rankine Cycles

January 27, 2017

Author(s)

Ian H. Bell, Kenneth G. Kroenlein, John P. O'Connell, Jens Abildskov, Jerome Frutiger, Gurkan Sin

This study presents a generic method to analyze and select equations of state (EoS) based on detailed uncertainty analysis of the respective EoS property parameters. A Cubic EoS (i.e. Soave-Redlich-Kwong SRK) is compared to PC-SAFT EoS. The uncertainty

Organic fluids for ORC systems: classification and calculation of thermodynamic and thermophysical properties

January 1, 2017

Author(s)

Ian H. Bell, Eric W. Lemmon

Automatic fitting of binary interaction parameters for multi-fluid Helmholtz-energy-explicit mixture models

September 26, 2016

Author(s)

Ian H. Bell, Eric W. Lemmon

In the highest-accuracy mixture models available today, those of the multi-fluid Helmholtz-energy-explicit formulation, there are a number of binary interaction parameters that must be obtained through correlation or estimation schemes. These binary

Viscosity of refrigerants and other working fluids from residual entropy scaling

July 15, 2016

Author(s)

Ian H. Bell, Arno R. Laesecke

The dynamic modeling of thermal systems and their components has gained an increased importance in recent years. Viscosity is one of the transport properties of fluids that are required for detailed analyses of system components, including compressors

Psychrometric Properties of Humid Air from Multi-Fluid Helmholtz-Free-Energy-Explicit Models

July 11, 2016

Author(s)

Ian H. Bell, Eric W. Lemmon, Allan H. Harvey

Psychrometric properties of humid air are widely used in the analysis and modeling of thermal systems. In this work we present a method for obtaining these properties from the multi-fluid mixture formulation forming the so-called GERG mixture model. This

Bubble Point Measurements of n-Propane + n-Decane Binary Mixtures with Comparisons of Binary Mixture Interaction Parameters for Linear Alkanes

July 1, 2016

Author(s)

Elisabeth Mansfield, Ian H. Bell, Stephanie L. Outcalt

To develop comprehensive models for multi-component natural gas mixtures (and other applications), it is necessary to have binary interaction parameters for each of the pairs of constituent uids that form the mixture. Good interaction parameters rely on a

Helmholtz energy translations for common cubic equations of state for use in one-fluid and multi- fluid mixture models

June 20, 2016

Author(s)

Ian H. Bell, Andreas Jaeger

Comprehensive and generalized derivations have been presented for the treatment of the residual part of the Helmholtz energy which arises from the transformation of several common cubic equations of state (Soave-Redlich-Kwong, Peng-Robinson and others of a

Thermophysical Properties of Carbon Dioxide and CO2-Rich Mixtures

May 9, 2016

Author(s)

Allan H. Harvey, Ian H. Bell, Marcia L. Huber, Arno R. Laesecke, Eric W. Lemmon, Christopher W. Meyer, Chris D. Muzny, Richard A. Perkins

This report summarizes the results of work performed under DOE/NETL Interagency Agreement DE- FE0003931, which began in October 2011 and ended (after a 6-month no-cost extension) March 31, 2015. The key objectives for this work were to: (1) Measure the dew

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