title: Degradation of phosphate ester hydraulic fluid in power station turbines investigated by a three-magnet unilateral magnet array.
abstract: A three-magnet array unilateral NMR sensor with a homogeneous sensitive spot was employed for assessing aging of the turbine oils used in two different power stations. The Carr-Purcell-Meiboom-Gill (CPMG) sequence and Inversion Recovery-prepared CPMG were employed for measuring the ¹H-NMR transverse and longitudinal relaxation times of turbine oils with different service status. Two signal components with different lifetimes were obtained by processing the transverse relaxation curves with a numeric program based on the Inverse Laplace Transformation. The long lifetime components of the transverse relaxation time T₂eff and longitudinal relaxation time T₁ were chosen to monitor the hydraulic fluid aging. The results demonstrate that an increase of the service time of the turbine oils clearly results in a decrease of T₂eff,long and T₁,long. This indicates that the T₂eff,long and T₁,long relaxation times, obtained from the unilateral magnetic resonance measurements, can be applied as indices for degradation of the hydraulic fluid in power station turbines.
authors.affiliation: State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, Chongqing 400044, China. guopan@cqu.edu.cn.
authors.forename: Pan
authors.initials: P
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, Chongqing 400044, China. hewei@cqu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: He
authors.affiliation: MRI Centre, Department of Physics, P.O. Box 4400, University of New Brunswick, Fredericton, NB E3B 5A3, Canada. juan.garcia@cbiomed.cu.
authors.forename: Juan C
authors.initials: JC
authors.lastname: García-Naranjo
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