Transducer Installation Effects on Pressure Measurements in PGC Devices

Gejji, Rohan; Walters, Ian V.; Beard, Sarah; Lemcherfi, Aaron; Sardeshmukh, Swanand V.; Heister, Stephen D.; Slabaugh, Carson D.

doi:10.2514/6.2018-0158

Cited by 29 publications

(9 citation statements)

References 7 publications

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“…This accounts for the precision and bias uncertainty of the measured pressure, but it does not include possible amplification or attenuation of the measured peak pressure due to the installation of the pressure transducer in a recessed cavity port. 44,45 As reported in Table 1, for Case A-1, the resulting pp−p′/pc is 124%, while for Case B-2, the pp−p′/pc is 5%.…”

Section: Resultsmentioning

confidence: 84%

“…All HF transducers are installed in a recessed cavity with a port resonance greater than 10 kHz and sampled at 180 kHz. 44,45 OH* and CH* are commonly used as qualitative markers of global heat release in combustion diagnostics. For the purposes of this work, the change in chemiluminescence intensity is assumed to be proportional to the heat release rate from the flame.…”

Section: Operation and Diagnosticsmentioning

confidence: 99%

“…All HF transducers are installed in a recessed cavity with a port resonance greater than 10 kHz and sampled at 180 kHz. 44,45…”

Section: Experiments Descriptionmentioning

confidence: 99%

See 2 more Smart Citations

Injector-coupled transverse instabilities in a multi-element premixed combustor

Philo

Gejji

Slabaugh

2020

International Journal of Spray and Combustion Dynamics

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Combustion instabilities in a high-pressure, multi-element combustor are studied in order to understand the relationship between the chamber and injector dynamics. A linear array of seven injectors supplies premixed natural gas and air into a rectangular combustion chamber designed to promote high-frequency, transverse thermoacoustic instabilities. The effect of equivalence ratio on the combustion dynamics was investigated for two injector lengths, 62.5 and 125 mm. For all operating conditions, the 125 mm injectors promote high-amplitude instabilities of the fundamental transverse (1T) mode, which has a frequency of 1750–1850 Hz. Reducing the injector length significantly lowers the instability amplitudes for all operating conditions and, for lower equivalence ratio cases, excites an additional mode near 1550 Hz. The delineating feature controlling the growth of the instabilities in each injector configuration is the coupling with axial pressure fluctuations in the injectors that occur in response to the transverse modes in the chamber.

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Section: Resultsmentioning

confidence: 84%

Section: Operation and Diagnosticsmentioning

confidence: 99%

See 1 more Smart Citation

Injector-coupled transverse instabilities in a multi-element premixed combustor

Philo

Gejji

Slabaugh

2020

International Journal of Spray and Combustion Dynamics

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“…A calibration test bed based on a hydrogen-oxygen predetonator for a pulsed detonation engine (PDE) as a source for the steep fronted pressure wave is designed in Ref. 24 to enable characterization of pressure sensors installed in the flush, receiver, and waveguide tube configuration. The sensor with the receiver of approximate volume V ≈ 44 mm 3 showed up to 28% amplitude attenuation and almost negligible time lag compared to the flush sensor, and the sensor installed in the waveguide tube with d ¼ 3.2 mm and L = 100 mm showed a significantly higher delay and as much as 54% reduction in the measured attenuated pressure amplitude.…”

Section: Introductionmentioning

confidence: 99%

“…What would be the measurement accuracy of the local instantaneous and timeaveraged static pressure in an RDE combustor when using a remote pressure sensor with the waveguide tubereceiver system and with a waveguide tube of relatively large diameter (on the order of several millimeters, like in Refs. 19,[21][22][23][24][25][26]? What would be the effect of such a measurement system on the frequency spectrum of the pressure signal?…”

Section: Introductionmentioning

confidence: 99%

Pressure measurements in detonation engines

Иванов

Фролов

Sergeev

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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The influence of waveguide tubes on the signals received by remote pressure sensors measuring pressure histories in pulsed detonation engines (PDEs) and rotating detonation engines (RDEs) is studied computationally. Two types of pressure sensors are considered: low-frequency static pressure sensors and high-frequency sensors of pressure pulsations. Three approaches to solving the problem are used: based on Euler (inviscid flow), Navier–Stokes (laminar flow), and unsteady Reynolds-averaged Navier–Stokes (turbulent flow) equations. The approaches based on the inviscid and laminar flow models are shown to provide the best predictive capability. The laminar flow model is applied to analyzing the readings of pressure sensors installed remotely in the waveguide tubes attached to the hydrogen-fueled PDE, RDE, and detonation ramjet (DR). It is shown that the measurements of static pressure and pressure pulsations by remote pressure sensors do not correspond to the time-averaged mean and local instantaneous values of pressure in the combustors. The pressure time histories can be recovered based on the measurements and computational fluid dynamics calculations of the operation process. The latter is demonstrated by analyzing the results of test fires with a dual-duct DR model.

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Optical pressure sensing at MHz rates via collisional line broadening of carbon monoxide: uncertainty quantification in reacting flows

et al. 2023

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An optical method for high-speed line-of-sight pressure measurements using infrared laser absorption spectroscopy is presented with detailed uncertainty analysis related to thermodynamic and compositional variation in combustion environments. The technique exploits simultaneous sub-microsecond sensing of temperature and mole fraction to extract pressure from collisional line broadening at MHz rates. A distributed-feedback quantum-cascade laser near 5 $$\upmu $$ μ m in a bias-tee circuit is used to spectrally resolve multiple rovibrational transitions in the P-branch of the fundamental band of carbon monoxide, which may be seeded or nascent to reacting flows. A comprehensive approach for estimating collisional line broadening in complex combustion gas mixtures is presented. Uncertainty is quantified for a wide range of conditions, reflecting different fuels, equivalence ratios, reaction progress, and combustion modes (deflagration and detonation), which influence gas composition and temperature. The sensor was evaluated for accuracy and precision in both a high-enthalpy shock-tube facility in hydrocarbon–air ignition experiments and behind ethylene–oxygen detonation waves in a detonation-impulse tube facility at temperatures from 1500 to 3000 K and pressures from 0.5 to 10 bar. Pressure measurements were compared to measurements by piezoelectric pressure transducers and to theoretical estimates from normal-shock and Chapman-Jouguet simulations. The high-speed path-integrated optical pressure measurement offers an alternative to traditional electromechanical transducers that are constrained to values at wall boundaries and have proven unreliable in some harsh reacting flows.

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Transducer Installation Effects on Pressure Measurements in PGC Devices

Cited by 29 publications

References 7 publications

Injector-coupled transverse instabilities in a multi-element premixed combustor

Injector-coupled transverse instabilities in a multi-element premixed combustor

Pressure measurements in detonation engines

Optical pressure sensing at MHz rates via collisional line broadening of carbon monoxide: uncertainty quantification in reacting flows

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