TUSTP 2003TUSTP 2003

By By Dong XiangDong Xiang

May 20, 2003May 20, 2003

DOE Project:StarCut Differential Dielectric

Sensor — Experiments and Modeling

TopicsTopics

Introduction Fundamentals of Microwave Measurements Measurement Methods of Permittivity Proposed Solution Future Plans

Introduction

StarCut is ChevronTexaco’s meter for continuous measurement of multiphase fluid composition

Microwave signal is used to measure dielectric properties of the fluids

At present, no analytical model is available for StarCut

TopicsTopics

Fundamentals of Microwave Measurements

Waveguide

Microwave Characterization

S-Parameter

Sensor Cell of StarCut

Transmitting Antenna Receiving Antenna

Fluid

Waveguide

Waveguide is used for efficient transfer of microwave signals from one point to another

In StarCut, rectangular waveguide is used

Microwave Characterization

Incident Wave

Reflected Wave

Transmitted Wave

Sample

Why Use S-Parameter?

It is very hard to measure total voltage and current at device ports

S-Parameter is relatively easy to obtain at high frequency

S-Parameter is related to familiar measurements (gain, loss, reflection coefficient)

S-Parameter Measurement

Topics

Measurement Methods of Permittivity Transmission Line Method

Reflection/Transmission Method Amplitude Attenuation + Phase

Shift S-Parameter

Transmission Line Equation Method Cavity Resonator Method

Full Wave Analysis Method Perturbation Theory Method

Transmission Line Method

Waveguide structure is modeled as transmission line

Transmission line parameters are measured to determine permittivity

Amplitude Attenuation and Phase Shift

Lookup Table Method (Hatton,Texaco, 1989)

This patent is the theoretical foundation of StarCut currently used in North Campus

Attenuation + phase shift + Database (lookup table)

Amplitude Attenuation and Phase Shift

Analytical method (Kraszewski, 1990)

Measurement has to be done twice using different thickness of sample

It is difficult for dynamic measurement

No hole-effect consideration

S-Parameter Method

S-Parameter is measured to determine permittivity (Marrelli, ChevronTexaco, 1997)

No hole-effect consideration

Transmission Line Equation Method

Transmission line equation and boundary condition are used to determine permittivity

This is the theoretical foundation of Huang’s Thesis (1997)

Polynomial fitting for hole-effect

Huang’s Model

Section 1

Section 2

Section 3

Cavity Resonator Method

Resonance frequency is measured to determine permittivity

Network analyzer is used to get resonance frequency

Advantage: hole-effect can be considered

Only valid for low-loss material, not useful for multiphase flow measurement

Full Wave Method

Resonance frequency is determined by electromagnetic equation and boundary condition

Advantage: hole-effect can be easily calculated

This is the theoretical foundation of Janezic, NIST (Colorado, 1999)

Perturbation Theory

Resonance frequency is determined using perturbation theory for material in cavity resonator

Advantage: hole-effect can be calculated

Disadvantage: too many assumptions affect the measurement accuracy

Topics

Proposed Solution:

Transmission Line Method

Solution: Model

Resonator method is not good for our case

Reason: multiphase fluid has high loss

Transmission line method is considered

Future Plans

Develop model for StarCut, minimize hole-effect

Hardware Improvement of StarCut

Use StarCut to measure other parameters in multiphase flow

Thank You!