Affiliations: [a] State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, Chongqing, Sichuan, China | [b] Chongqing Normal University, Chongqing, Sichuan, China
Correspondence:
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Corresponding author: Yajie Zhang, State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, Chongqing, Sichuan 400044, China. Tel.: +86 023 6510 5242; E-mail:20094281@cqu.edu.cn
Abstract: This paper presents a simple design for a nuclear
magnetic resonance (NMR) sensor and its application for detecting turbine
oil in two power stations. The magnet, which is composed of two identical
cuboid permanent magnet blocks and two iron shimming sheets of a special
shape, generates a relatively homogeneous static magnetic B0 field
(∼ 364 ppm) on a 10 × 10 mm2 region of interest. In the
vertical direction, it produces a constant gradient of ∼15.5 T/m
within 5 mm which allows for self-diffusion measurements and 1 dimensional
imaging. This NMR sensor can produce a deep penetration depth into the
samples with relatively strong and uniform B0 strength. The NMR sensor
was specially designed for assessing the aging status of turbine oil in a
power station, and a group of turbine oil of different service times was
measured. Results demonstrate that an increase in the service time of the
turbine oils clearly decreases transverse relaxation time T2. This
portable sensor can be used in fields and provide quantitative evaluation
parameters of the aging status of turbine oil during periodic inspection.
