Purpose




The conventional strain gauge type pressure sensor suffers in static testing of engines due to the contact transduction method. This paper aims to focus on the concept of non-contact transduction-based pressure sensor using eddy current displacement sensing coil (ECDS) to overcome the temperature limitations of the strain gauge type pressure sensor. This paper includes the fabrication of prototypes of the proposed pressure sensor and its performance evaluation by static calibration. The fabricated pressure sensor is proposed to measure pressure in static test environment for a short period in the order of few seconds. The limitations of the fabricated pressure sensor related to temperature problems are highlighted and the suitable design changes are recommended to aid the future design.




Design/methodology/approach




The design of ECDS-based pressure sensor is aimed to provide non-contact transduction to overcome the limitations of the strain gauge type of pressure sensor. The ECDS is designed and fabricated with two configurations to measure deflection of the diaphragm corresponding to the applied pressure. The fabricated ECDS is calibrated using a standard micro meter to ensure transduction within limits. The fabricated prototypes of pressure sensors are calibrated using dead weight tester, and the calibration results are analyzed to select the best configuration. The proposed pressure sensor is tested at different temperatures, and the test results are analyzed to provide recommendations to overcome the shortcomings.




Findings




The performance of the different configurations of the pressure sensor using ECDS is evaluated using the calibration data. The analysis of the calibration results indicates that the pressure sensor using ECDS (coil-B) with the diaphragm as target is the best configuration. The accuracy of the fabricated pressure sensor with best configuration is ±2.8 per cent and the full scale (FS) output is 3.8 KHz. The designed non-contact transduction method extends the operating temperature of the pressure sensor up to 150°C with the specified accuracy for the short period.




Originality/value




Most studies of eddy current sensing coil focus on the displacement and position measurement but not on the pressure measurement. This paper is concerned with the design of the pressure sensor using ECDS to realize the non-contact transduction to overcome the limitations of strain gauge type pressure sensors and evaluation of the fabricated prototypes. It is shown that the accuracy of the proposed pressure sensor is not affected by the high temperature for the short period due to non-contact transduction using ECDS.

Design, development and performance evaluation of pressure sensor using eddy current displacement sensing coil

In Aerospace applications, transient pressure measurement in harsh environment using strain gauge type of pressure sensor, suffers due to the limitations of strain gauges and contact transduction method. In this paper, a novel pressure sensor using eddy current principle has been proposed with complete design to overcome the challenges faced by the other type of pressure sensors in harsh environment. Unlike magnet based transduction, the designed pressure sensor does not require recalibration after every use as the target will not loose its properties for short duration of high temperature exposure. The performance evaluation of the designed sensor supported by simulated test results is presented for analysis and improvement. Further scope of work towards improvement of accuracy, bandwidth and miniaturization has been concluded to aid sensor design in future.

A novel pressure sensor using eddy current principle for Harsh environment

A pressure sensor with non-contact transduction which measures deflection of diaphragm due to applied pressure, using tunneling magnetoresistive (TMR) principle is aimed to meet the requirements of pressure measurement in harsh environments. In commonly used strain gauge type of pressure sensor, strain depends not only on pressure but also on media temperature which induces more error or burnout strain gauges at high temperature. A novel non-contact measurement principle to detect diaphragm deflection is proposed that allows to overcome these limitations. For this purpose, Samarium Cobalt magnet and TMR sensor are used. As transduction is non-contact, this method is useful to measure pressure of hot gas produced by combustion of short duration. This paper presents the design of pressure sensor using TMR principle and its evaluation supported by the simulated test results. Further scope of work towards improvement of accuracy and confidence on pressure measurement has been concluded to aid sensor design in future.

K Gobi

Papers

A novel pressure sensor using eddy current principle for Harsh environment

Design of non-contact transduction based pressure sensor using Tunneling magnetoresistive (TMR) principle