Gang Xu

US Patent:

7676352, Mar 9, 2010

Filed:

Apr 19, 2005

Appl. No.:

11/109840

Inventors:

David J. Van Peursem - Irvine CA, US
Gang Xu - Corona CA, US

Assignee:

Invensys Systems, Inc. - Foxboro MA

International Classification:

G06F 9/455

US Classification:

703 9, 703 2, 73 2501, 137828

Abstract:

A method of estimating a thermophysical property of a fluid using a local model is disclosed herein. The method includes generating, for use within the local model, a series expansion of thermodynamic equations relating to the thermophysical property and one or more derivatives involving the thermophysical property. The method further includes evaluating, based upon a set of specified values of parameters of the fluid, a first order term of the series expansion and a second order term of the series expansion. The values of the first order term and the second order term are then compared. A value of the thermophysical property is then automatically updated when the values of the first order term and the second order term are found to differ by more than a predefined amount.

US Patent:

7987082, Jul 26, 2011

Filed:

Feb 1, 2010

Appl. No.:

12/698063

Inventors:

David J. Van Peursem - Irvine CA, US
Gang Xu - Corona CA, US

Assignee:

Invensys Systems, Inc. - Foxboro MA

International Classification:

G06F 9/455

US Classification:

703 9, 73 2501

Abstract:

A method of estimating a thermophysical property of a fluid using a local model is disclosed herein. The method includes generating, for use within the local model, a series expansion of thermodynamic equations relating to the thermophysical property and one or more derivatives involving the thermophysical property. The method further includes evaluating, based upon a set of specified values of parameters of the fluid, a first order term of the series expansion and a second order term of the series expansion. The values of the first order term and the second order term are then compared. A value of the thermophysical property is then automatically updated when the values of the first order term and the second order term are found to differ by more than a predefined amount.

US Patent:

8165860, Apr 24, 2012

Filed:

Aug 25, 2009

Appl. No.:

12/547145

Inventors:

Gang Xu - Irvine CA, US
David Bluck - Yorba Linda CA, US
David J. Van Peursem - Irvine CA, US
Ian H. Boys - Vista CA, US

Assignee:

Invensys Systems, Inc - Foxboro MA

International Classification:

G06F 9/455

US Classification:

703 12

Abstract:

A system for thermodynamic modeling is provided. The system comprises a computer having a processor, a thermodynamic process simulation application, and a thermodynamic equation of state application. When executed by the processor, the thermodynamic equation of state application determines a density root based on a first and second point of departure from an equation of state and based on a first and a second extrapolation equation. The first departure point satisfies the equation.

US Patent:

8364316, Jan 29, 2013

Filed:

Sep 15, 2009

Appl. No.:

12/560134

Inventors:

Gang Xu - Irvine CA, US
David Bluck - Yorba Linda CA, US

Assignee:

Invensys Systems, Inc. - Foxboro MA

International Classification:

G01N 15/06
G01N 33/00
G01N 33/48

US Classification:

700270, 700 1, 700266, 702 22, 702 30, 702 31, 702127

Abstract:

A method of modeling phase characteristics of thermodynamic systems utilizing pseudo-properties strategy and a reduced number of variables is disclosed herein. The method describes a means of determining the probability of phase splitting of mixtures of materials at a given temperature, pressure, and composition by characterizing the functions that describe the system via pseudo-properties, and also by describing the system in n−1 or fewer variables, where n represents the number of components in the system of interest. In an embodiment, a multi-component system is characterized in one variable, thereby providing simplified thermodynamic models in a time-efficient manner. In addition, the information generated by this reduced-variable calculation can further be used as a starting point for calculations of equations of state.

US Patent:

20200050158, Feb 13, 2020

Filed:

Oct 18, 2019

Appl. No.:

16/657833

Inventors:

- Lake Forest CA, US
Gang Xu - Irvine CA, US

International Classification:

G05B 17/02

Abstract:

Simulation of process control environments, including dynamic properties, with a modified first-order Taylor series expansion. By using more linear calculations, a physical dynamic property is approximated in less time and with fewer computing resources. By adjusting the approximation to introduce curvature, a physical dynamic property is represented over a wider range than with basic linear series expansions. A comparison to a basic linear first-order series expansion identifies conditions when a rigorous update of a dynamic property is needed.

US Patent:

20170115644, Apr 27, 2017

Filed:

Oct 22, 2015

Appl. No.:

14/919887

Inventors:

- Foxboro MA, US
Gang Xu - Irvine CA, US

Assignee:

Invensys Systems, Inc. - Foxboro MA

International Classification:

G05B 17/02

Abstract:

Simulation of process control environments, including dynamic properties, with a modified first-order Taylor series expansion. By using more linear calculations, a physical dynamic property is approximated in less time and with fewer computing resources. By adjusting the approximation to introduce curvature, a physical dynamic property is represented over a wider range than with basic linear series expansions. A comparison to a basic linear first-order series expansion identifies conditions when a rigorous update of a dynamic property is needed.