Use of a detailed theoretical model has allowed the optimization of the design of a high sensitivity accelerometer, based on a fiber Bragg grating (FBG) and an accelerometer based on this design has been demonstrated experimentally. With a universal model based on double-point encapsulation established, the performance of the device in terms of its optimal sensitivity and frequency distribution has been analyzed, with an optimization 'figure of merit' using the product of the sensitivity and the resonant frequency being presented. The experimental results obtained indicate that the FBG-based accelerometer thus developed shows a broad, flat frequency band, a corresponding flat range sensitivity of ∼152.0pm/G, a resonant frequency of 441.0Hz, and a cross-axis sensitivity of less than 3.6% of the main-axis sensitivity. An accelerometer of this type and with this performance thus has the potential for the important field of low frequency oil-gas seismic exploration.

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Abstract. Regarding the importance of wet saturated steam dryness measurement, at the same temperature and pressure the dielectric constant of water is much greater than that of steam. When the wet steam flows by the capacitive sensor, the sensor capacitance changes with the steam wetness. A new method that barrel capacitor is presented to provide real-time and in-line measurement of steam quality. According to the calculation results and the theory data calibration, thus the present method solves the problems associated with industrial steam boilers and steam injection wells dryness in-line measurement.