Transcript Proposal
TUSTP 2003 DOE Project: StarCut Differential Dielectric Sensor — Experiments and Modeling By Dong Xiang May 20, 2003 Topics 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 Topics Fundamentals of Microwave Measurements Waveguide Microwave Characterization S-Parameter Sensor Cell of StarCut Fluid Transmitting Antenna Receiving Antenna Waveguide Waveguide is used for efficient transfer of microwave signals from one point to another In StarCut, rectangular waveguide is used Microwave Characterization Sample Incident Wave Reflected Wave Transmitted Wave 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 2 Section 1 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!