Abstract The non-invasive nature of optical diagnostic techniques is advantageous in studying micronozzles, as it safeguards the undisturbed highly sensitive micro-scale flow field. In this work, a laser-based interferometric Mie scattering system developed using virtually imaged phased array to quantitatively measure one-dimensional velocity profile at exit micronozzles. A narrow-linewidth solid-state laser used light source, acetone-seeded air gas, and estimated from Doppler shift...

The design and testing of a gas temperature velocity scramjet engine inlet sensor based on tunable diode laser absorption spectroscopy oxygen is discussed. robustness stability the optical necessitated by dynamic vibrational thermal environment were balanced against need for compact size very high signal-to-noise ratio in low-pressure, high-altitude flight regime. Test results demonstrated good mechanical an adequate altitudes up to 30 km with predicted absorbance peaks greater than signal...

A 10-kHz one-dimensional Rayleigh-CH4 Raman instrument capable of achieving highly precise measurement temperature and methane mole fraction is demonstrated. The system uses a pulse-burst laser as the light source back-illuminated electron-multiplied CCD cameras detectors. are operated in subframe burst gating mode, to combine high sampling rate, low noise, slow readout. improved precision this configuration demonstrated by measuring fractions ambient gas mixtures non-premixed inverse...

A numerical method is presented for measuring angle of attack and Mach number in the inlet a supersonic combustor using sensor design based on tunable diode laser absorption spectroscopy. nonlinear least-squares fitting routine was applied to simultaneously retrieve freestream simple two-dimensional with known conical simulated spectrum. The spectrum spanned over five transitions -band molecular oxygen. In presence 15% white Gaussian background noise, converged actual value standard...

The work introduces a VIPA-based interferometric Rayleigh scattering instrument for tracer-free, simultaneous temperature and velocity measurements along 1D volume. A virtually imaged phased array (VIPA) replaces the Fabry-Perot etalon conventionally used in scattering, allowing extension of technique from 0D (point or multi-point) to 1D. Rayleigh-Brillouin spectrum is function pressure can be diagnostics isobaric flows. reference leg based on (FP) provides real-time monitoring laser...

The two-color ratio pyrometry technique using a digital single-lens reflex camera has been used to measure the time-averaged and path-integrated temperature distribution in radiating shock layer high-enthalpy flow. A 70 mm diameter cylindrical body with long spike was placed hypersonic tunnel, region behind investigated. systematic error due contributions from line emissions corrected by monitoring emission spectrum this spectrometer. relative on R, G, B channels of were 7.4%, 2.2%, 0.4%,...

Log-ratio detection is a convenient technique for making temperature and concentration measurements using sensors based on tunable diode laser absorption spectroscopy. In many practical sensing applications, it difficult to avoid stray light falling the signal photodiode of sensor. This acts as noncommon-mode interference introduces systematic error in measurements, which not removed by baseline subtraction. paper analyzes factors that determine this also presents calibration method can...

The performance of a scramjet inlet sensor based on tunable diode laser absorption spectroscopy oxygen in the A-band near 760 nm during low-altitude, subsonic flight test is discussed. Though did not reach targeted hypersonic regime due to malfunction first-stage booster, analysis spectral data acquired descent below 3 km successfully determined pressure and temperature demonstrated that system was capable producing an adequate signal-to-noise ratio allow temperature, pressure, velocity...

The performance of a gas temperature and velocity sensor based on tuneable diode laser absorption spectroscopy (TDLAS) oxygen in scramjet engine inlet during flight test is discussed. This the first flight-tested TDLAS designed specifically for measuring flow under conditions. robustness stability design dynamic load conditions were made evident by quality data delivered after very unstable high-g launch scenario. did not reach targeted altitude-velocity regime. However, analysis...

One-dimensional interferometric Rayleigh scattering velocimetry is demonstrated using a virtually imaged phased array (VIPA). A continuous-wave laser emitting at 532 nm used as the source, and low-noise CCD camera detector. The VIPA has free spectral range of 15 GHz coated for wavelength 500-600 nm. Velocity measurements different flow rates show an accuracy 10 m/s. Demonstration high-speed velocity measurement conducted in jet air through contoured converging nozzle. Factors considered...

A filtered Rayleigh scattering system is developed and applied to measure the mole fraction of methane in a methane-air swirl flow through transparent conical quartz quarl. Light from location where laser beam incident on surface quarl orders magnitudes larger than gas mixture interest. This diffusive suppressed using molecular absorption by an iodine cell spatial filtering optical aperture. Residual stray light accounted for up 5% total signal had be removed accurate measurements. The...

This paper presents a comprehensive study on the design and performance evaluation of circular rectangular microstrip patch antennas tailored for 5G applications, operating at 25 GHz. Utilizing Teflon Rogers substrates with superior dielectric properties, are meticulously crafted rigorously analyzed. The explores methodology, simulation outcomes, compares antennas, focusing their suitability systems. Through iterative simulations optimizations, fine-tuned to achieve optimal parameters,...

A method for measuring the velocity of liquid droplets emanating from an effervescent injector into ambient air was experimented using a mixture acetone and water. Conventional methods such as Laser Doppler Velocimetry Particle Image Velocimetry, which utilise Mie-scattering, have limitations due to multiple scattering strong surface reflections, respectively. In current study, we demonstrate fluorescence-based particle image velocimetry, can overcome abovementioned difficulty. Unlike...