TUSTP 2003 By Dong Xiang May 20, 2003 By Dong Xiang May 20, 2003 DOE Project: StarCut Differential Dielectric Sensor — Experiments and Modeling 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!