Optimized conditions of Schlieren photography

Bunjong, D; Pussadee, N; Wattanakasiwich, Pornrat

doi:10.1088/1742-6596/1144/1/012097

Cited by 11 publications

(7 citation statements)

References 2 publications

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“…The sharp blade light block used was satisfactory. Some initial testing was done with a wire light block similar to [36,42,53] but the sharp blade produced clearer images. The superiority of the blade as a light block is unexpected given literature states a wire light block generally leads to fewer diffraction effects [28].…”

Section: Schlieren Imager -Initial Resultsmentioning

confidence: 99%

Using Schlieren Imaging and Radar Acoustic Sounding System for the Detection and Characterization of Close-in Air Turbulence

Gordon,

Brooker

2023

Preprint

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This paper presents a novel sensor for the detection and characterization of regions of air turbulence that would be of use to improve UAV stability in bad weather. It consists of a combined Schlieren imager and a Radar Acoustic Sounding System (RASS) to produce dual modality “images” of air movement within the measurement volume. The ultrasound modulated Schlieren imager consists of a strobed point light source, parabolic mirror, light-block and camera which are controlled by two laptops. It provides a fine scale projection of the acoustic pulse modulated air turbulence through the measurement volume. The narrow beam 40 kHz/ 17 GHz RASS produces spectra based on Bragg enhanced Doppler radar reflections from the acoustic pulse as it travels. Tests using artificially generated air vortices showed some disruption of the Schlieren image and of the RASS spectrogram. This should allow the higher resolution Schlieren images to identify the turbulence mechanisms that are disrupting the RASS spectra.

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Section: Schlieren Imager -Initial Resultsmentioning

confidence: 99%

Using Schlieren Imaging and Radar Acoustic Sounding System for the Detection and Characterization of Close-in Air Turbulence

Gordon,

Brooker

2023

Preprint

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“…The setup comprised a spherical concave mirror (160 mm diameter, 1300 mm focal distance), an LED point light source (4 V, 120 mW, cool white 9000 K) and a scalpel blade. Images were acquired using a Nikon D90+ with an 18-200 mm telephoto lens with fixed settings (manual focus on the target, ISO400, shutter speed 1/800, f5.6, no bracketing, spot metering exposure) based on Bunjong et al [28]. The catheter was placed horizontally 50 mm in front of the mirror to observe buoyancy effects more clearly [26] with the scalpel blade parallel for optimal visualization [26].…”

Section: Schlieren Imagingmentioning

confidence: 99%

Effect of gas flow on a helium/oxygen endoscopic plasma jet

Thulliez¹,

Bastin²,

Rémy³

et al. 2022

J. Phys. D: Appl. Phys.

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This experimental study characterized the effect of carrier gas flow on an endoscopic plasma jet. This system generates and transports helium plasma in a tube over several meters, along with a separate channel transporting oxygen to enhance plasma reactivity on site. The resulting plasma plume exiting the tube allows treatment of tissue surfaces in an endoscopic setting with a view to perform therapeutic operations in the gastrointestinal tract. In a closed cavity simulating the tract, the carrier gas flow was studied by a combined approach investigating plasma plume chemistry, fluid dynamics, and plasma effects on the surface of a hydrogel tissue model reporting oxidation. These three aspects are shown to be closely inter-related. Plasma plume length, intensity, and shape strongly depend on helium content, velocity, turbulence, and environment. Optical emission spectroscopy was used to show that the helium gas flow rate increases the amount of helium and reactive oxygen species (ROS) in the plume. Schlieren imaging was used to visualize the transition of the fluid from buoyant to laminar and finally turbulent depending on flow rate, with a backflow in a closed cavity. Finally, the frontal and radial treatment of the cavity was assessed by measuring ROS delivery to a KI-starch agarose gel model. Helium flow rate had a noticeable effect on the treatment distribution profile and treatment intensity, with different maxima for frontal and radial treatments. This combined approach, in an accurate simulation of the target configuration (i.e. a closed, cylindrical cavity), is necessary to optimize treatment, as its outcome depends on a balance between ROS production, transport, and distribution.

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“…In the present study, the data of flame flashback and flame blow-off were obtained by visual observation using an AOS-Q-PRI portable high-speed camera and a large concave mirror with a diameter of 40.5 cm and a focal length of 68 cm depending on the principles of the Schlieren photography technique (Bunjong, et al [16]), as shown in Figure 4. The mixing process used was based on Gibbs-Dalton Law of the partial pressure for each mixture component to obtain an accurate equivalence ratio.…”

Section: Experimental Rig and Test Proceduresmentioning

confidence: 99%

Experimental Investigation of LPG/H2/Air Premixed Flame Stability Zone

AbdulAmeer

Shahad

Abdulhaleem

2020

J. Eng. Technol. Sci.

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The combustion system in this study was designed to work with Iraqi liquefied petroleum gas (ILPG) blended with hydrogen gas, consisted of non-swirling burners with different diameters, a mixture preparation unit operating on the principle of partial pressure of components according to the Dalton law and a high-speed camera, and was aimed to investigate the flame stability zone (flame flashback and blow-off).  The laminar boundary layer mechanism described by Lewis and von Elbe for flame flashback and blow-off limits was adopted with high-speed recordings and observations of flow rate at flame flashback and blow-off.  Fuel mixtures of ILPG and hydrogen gas with different equivalence ratios from (0.6-1.4) with an increment of 0.2 were used.  The combustion system was operated at atmospheric conditions (298K and 1 bar) for the unburned mixture.  The effect of burner diameter, equivalence ratio and hydrogen blending ratio on the flame stability zone was investigated.

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Optimized conditions of Schlieren photography

Cited by 11 publications

References 2 publications

Using Schlieren Imaging and Radar Acoustic Sounding System for the Detection and Characterization of Close-in Air Turbulence

Using Schlieren Imaging and Radar Acoustic Sounding System for the Detection and Characterization of Close-in Air Turbulence

Effect of gas flow on a helium/oxygen endoscopic plasma jet

Experimental Investigation of LPG/H2/Air Premixed Flame Stability Zone

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