Film Thickness Measurement Technique by Ultrasonic Transducer Inspire the Next Author: Ilan Wyn Davies Date: June - August 2016 1
Outline Ø Introduction Ø Ultrasonic Pulse-echo Method Ø Conventional vs Present Signal Processing Ø Conclusion Ø Questions 2
Introduction to Ultrasonic Transducer Purpose : - To Measure the Thickness of Liquid Film Why? - Stable operation of BWR core Goal of this Work : - To Improve the Technique based on the Experimental Data 3
Method of Ultrasonic Transducer Ø Liquid Film Thickness (δ) is calculated from Time Lag t Ø c - the speed of sound within saturated water Ø Utilizes Ultrasonic Reflection at the liquid film Ø Piezoelectric element (5 Hz) Ø Sonar Rader like way δ = c t 2 4
Method of Ultrasonic Transducer 5
Conventional Signal Processing (Prepared) Ø Time lag calculated via cross-correlation Steps: 1. Gain Difference wave : Observed wave from measurement Reference wave from Single-phase experiment 2. Cross-Correlation : between Difference and Reference wave 3. Time Lag at Maximum Cross-Correlation 6
Conventional Signal Processing (Prepared) Cross-correlation [-] 1 0.8 0.6 0.4 0.2 0-0.2-0.4-0.6-0.8-1 0 200 400 600 800 1000 Time lag [ns] 7
Single-phase Experiment (Prepared) Ø Establish reference wave for conventional signal processing. Ø Previously prepared. Ø Pulse echo at mock-up fuel rod wall within water Ø Under BWR conditions Ø Higher Density, Higher impedance thus change speed of sound value. Ø Data change in two-phase flow 8
Present Signal Processing (Hidden) Ø Finds the Reference wave hidden in measurement data Ø Histogram Method - focus and extract hidden single-phase signals in measured data Ø Utilizes the hidden potential of the weak signals Ø Real-time data 9
Present Signal Processing (Hidden) Yellow line - Hidden Reference Red and Green point Time lag 10
Condition H, Churn. Water Flow Rate: 150 kg/h, Steam Flow Rate: 35kg/h Film Thickness Cross-Correlation 11
Condition H, Churn. Water Flow Rate: 150 kg/h, Steam Flow Rate: 35kg/h Frame #327 Frame #406 12
Condition A, Annular Water Flow Rate: 150 kg/h, Steam Flow Rate: 200kg/h Film Thickness Cross-Correlation 13
Condition A, Annular Water Flow Rate: 150 kg/h, Steam Flow Rate: 200kg/h Frame #715 14
Condition F, Annular Water Flow Rate: 600 kg/h, Film Thickness Steam Flow Rate: 200kg/h Cross-Correlation 15
Condition F, Annular Water Flow Rate: 600 kg/h, Steam Flow Rate: 200kg/h Frame #210 Frame #580 16
Unknown Reflection Ø By Physical behaviour of the Liquid Film Flow Ø Large Curvature of Liquid Film Ø Ultrasonic Reflection Scattered Ø Lens Effect 17
Threshold Processing Ø Introducing Threshold / Limits Ø Avoid Random Errors from Unknown Reflection Ø Provide more Accurate Signal Processing Ø More Sensitively Detection of Liquid-film Thickness 18
Conclusion Ø Present Processing Best. Ø With Higher Cross-Correlation Ø Utilizes the hidden potential of the weak signals Ø Low Cross-Correlation assumed to detect water phase region Ø More Defined Detection of Liquid Film Ø Detected via Histogram Method. Ø Threshold Method Ø Removes the Noisy Plots Ø More Continuous, Effective Plot Ø Still Hidden Potential for Improvement 19
Thank You for Listening Questions? Inspire the Next A Summer Internship Project with Hitachi, Japan 20