Overcoming Thermal Challenges to Acquire Absolute Pressure Measurements in Rotating Detonation Engines Using Piezoresistive Pressure Transducers

Presently, piezoelectric (PE) pressure transducers in a recessed configuration are used to acquire the time-varying pressure in rotating detonation engines (RDEs). In addition, the capillary tube averaged pressure (CTAP) configuration with a low-frequency transducer is used to obtain the time-averaged pressure. The purpose of this research is to acquire high-fidelity absolute pressure measurement using a single piezoresistive (PR) transducer. First, a proprietary PR transducer with a pressure rating of 20 MPa is implemented. The Wheatstone bridge with a 5th-wire circuit and related analysis procedures are introduced to measure the probe temperature simultaneously with pressure measurements. The sensor calibration is performed to obtain correlation between (a) sensor temperature and 5th-wire voltage output and (a) sensor temperature and zero-offset voltage output. The sensor was implemented in recessed configuration into an RDE. Thermal compensation was effective after initial transients subsided, resulting in matching time-varying pressure from both PE and PR transducers. However, the time-averaged pressure deviated significantly from the corresponding CTAP measurements.Second, a commercial PR sensor with a maximum pressure rating of 3.5 MPa was thermally calibrated and implemented in an RDE. Four separate recessed probe mounts (two port diameters and two recess lengths) were used to investigate the trade-off between thermal protection of the sensor and attenuation of time-varying pressure measurements. The study shows that the port diameter must be large (closer to transducer diameter) to minimize attenuation of time-varying pressure, but the smaller diameter port shielded the sensor and provided time-averaged pressures matching those from the CTAP probe. Finally, a commercial PR sensor is used with a maximum pressure of 1.5 MPa is thermally calibrated and implemented in an RDE. Three separate actively water-cooled jackets are manufactured having the large port diameter of the previous study and different port lengths. The test duration is limited by hardware and/or by sensor temperature. Results show a near-perfect match of time-averaged pressure between PR and CTAP probes, proving for the first time that CTAP probes indeed measure time-averaged pressure. The PR transducer successfully acquired front-ended absolute pressure signal in long-duration RDE tests, at a sensitivity greater than that of current PE transducers.

Grantor dc:publisher

University of Alabama Libraries

Year dc:date.issued

2025

Author dc:creator

• Miller, Robert

Advisor dc:contributor.advisor

• Agrawal, Ajay K.

Contributors dc:contributor

• Branam, Richard
• Bittle, Joshua
• Khandelwal, Bhupendra
• Krishnan, Sundar

• Gas Turbines
• Propulsion
• Rotating Detonation Engine
• Thermal Compensation

Statement dc:rights

• All rights reserved by the author unless otherwise indicated.

Language dc:language.iso

en_US, English

Dc Identifier Other

1184397

OAI identifier oai:identifier

oai:ir.ua.edu:123456789/17588