Dual-Modality Capacitive-Ultrasonic Sensing for Measuring Floating Oil Spill Thickness

• Published in: IEEE transactions on instrumentation and measurement Vol. 71; p. 1
• Main Authors: Saleh, Mahdi, Tabikh, Ali Rida, Elhajj, Imad H., McKinney, Kristi, Asmar, Daniel
• Format: Journal Article
• Language: English
• Published: New York IEEE 2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acoustics; Capacitive sensors; dual-modality sensing; multiphase mixtures; Film thickness; Ground truth; In situ measurement; Oil slicks; Oil spills; oil thickness; Oils; Real time; Remote sensing; Sensor arrays; Sensors; Test facilities; Thickness measurement; Time measurement; ultrasonic sensors; Ultrasonic variables measurement
• ISSN: 0018-9456; 1557-9662
• DOI: 10.1109/TIM.2022.3212108

During oil spills, an accurate estimate of the oil-slick thickness at different locations within the affected area is an essential requirement to estimate the spilled amount, assess and enhance the performance of skimmers, and decide on type of remediation techniques to be applied such as in situ burning. This requirement cannot be satisfied using remote sensing techniques, which can provide a global assessment of the oil spill extent but not an accurate localized estimate of its thickness, particularly for thicker oil slicks. To solve this problem, we propose a new in situ measurement system that works based on a dual-modality sensing concept, combining capacitive and ultrasonic sensors to provide accurate information about the oil-film thickness in real-time. In this article, we describe the design, implementation, and testing of the proposed system, which was realized as two different devices optimized for different sensing use cases, including a handheld and a skimmer-mount device. The handheld device is intended for use in two scenarios: (1) experimental ground truth to verify oil thickness measurements during experiments at testing facilities, and (2) from vessels to obtain sample measurements in the field. The skimmer-mount device is optimized for mounting on skimmers, buoys, or in an oil spill boom apex to provide thickness data continuously under field conditions. The proposed devices were tested at the Cold Regions Research and Engineering Laboratory (CRREL) against different types of oil, in different installation modes, and under static/dynamic liquid conditions. The experimental results demonstrated their ability in providing real-time measurements with high accuracy and precision and without relying on any calibration against different types of water or oil.