Measurement of temperature and velocity fields in a convective fluid flow in air using schlieren images

Martínez-González, Adrián; Moreno-Hernández, D.; Guerrero-Viramontes, J.A.

doi:10.1364/ao.52.005562

Cited by 28 publications

(5 citation statements)

References 22 publications

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“…Schlieren imaging [40][41][42][43] ) of these systems would be valuable but are beyond the scope of this investigation. Finally, the data presented thus far indicates that the cluster dynamics and streamer formation characteristics in oil are similar to those seen in water but with a number of interesting caveats (for example, local fluid heating and the narrow nature of the extended streamer observed).…”

Section: Please Do Not Adjust Margins Please Do Not Adjust Marginsmentioning

confidence: 99%

Cavitation clusters in lipid systems – surface effects, local heating and streamer formation

Birkin

Foley

Truscott

et al. 2017

Phys. Chem. Chem. Phys.

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Cavitation clusters and streamers are characterised in lipid materials (specifically sunflower oil) and compared to water systems. The lipid systems, which are important in food processing, are studied with high-speed camera imaging, laser scattering and pressure measurements. In these oils, clusters formed at an aged (roughened) tip of the sound source (a piston like emitter, PLE) are shown to collapse with varied periodicity in relation to the drive amplitude employed. A distinct streamer (an area of increased flow emanating from the cavitation cluster) is seen in the lipid media which is collimated directly away from the tip of the PLE source whereas in water the cavitation plume is visually less distinct. The velocity of bubbles in the lipid streamer near the cluster on the order of 10 m s -1. Local heating effects, within the streamer, are detected using a dual thermocouple measurement at extended distances. Viscosity, temperature and the outgassing within the oils are suggested to play a key role in the streamer formation in these systems.

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Section: Please Do Not Adjust Margins Please Do Not Adjust Marginsmentioning

confidence: 99%

Cavitation clusters in lipid systems – surface effects, local heating and streamer formation

Birkin

Foley

Truscott

et al. 2017

Phys. Chem. Chem. Phys.

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“…Temperature measurements using Z-type schlieren systems were demonstrated in turbulent flames employing multiple-angle tomography [5], rather than the Abel transform used in the previous studies, and in semi-2D convective layers [17], also demonstrating good accuracy. Most of existing quantitative studies used experiments with ample optical access and basic flow configurations; however, in many important cases, like inside the cylinder of IC engines, optical access can be restricted and the flow field is not symmetric.…”

Section: Introductionmentioning

confidence: 91%

Using Infrared Laser Absorption to Measure Hydrocarbon Concentration in a Lean-Burn, Stratified-Charge, Spark-Ignition Engine

Charalambides

Hardalupas

Soulopoulos

et al. 2015

Combustion Science and Technology

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Schlieren [1, 2] is a non-intrusive technique that can be used to detect density variations in a medium, and thus, under constant pressure and mixture concentration conditions, measure whole field temperature distributions.The objective of the current work was to design a schlieren system to measure line-of-sight averaged temperature distribution with the final aim to determine the temperature distribution inside the cylinder of Internal Combustion engines. In a preliminary step, we assess theoretically the errors arising from the data reduction used to determine temperature from a schlieren measurement and find that the total error, random and systematic, is less than 3%, for typical conditions encountered in the present experiments. A Z-type, curved-mirror schlieren system was used to measure the temperature distribution from a hot air jet in an open air environment in order to evaluate the method. Using the Abel transform, the radial distribution of the temperature was reconstructed from the line of sight measurements. There was good agreement in the peak temperature between the reconstructed schlieren and thermocouple measurements. Experiments were then conducted in a four-stroke, single-cylinder, optical spark ignition engine with a four-valve, pentroof-type cylinder head to measure the temperature distribution of the reaction zone of an iso-octane-air mixture. The engine optical windows were designed to produce parallel rays and allow accurate application of the technique. The feasibility of the method to measure temperature distributions in IC engines was evaluated with simulations of the deflection angle combined with equilibrium chemistry calculations that estimated the temperature of the reaction zone at the position of maximum ray deflection as recorded in a schlieren image. Further simulations showed that the effects of exhaust gas recirculation and air-to-fuel ratio on the schlieren images were minimal under engine conditions compared to the temperature effect. At 20 crank angle degrees before top dead centre (i.e. 20 crank angle degrees after ignition timing), the measured temperature of the flame front was in agreement with the simulations (730-1320 K 2 depending on the shape of the flame front). Furthermore, the schlieren images identified the presence of hot gases ahead of the reaction zone due to diffusion and showed that there were no hot spots in the unburned mixture.

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“…Schlieren photography is another wavefront imaging technology for macro wavefront disturbances which is used to capture flows of fluids of varying densities [20][21][22]. It is widely used in aeronautical engineering to photograph the flow of air around an object.…”

Section: Schlieren Photographymentioning

confidence: 99%

Optical Wavefront Detection: A Beginner Tutorial

Zheng¹,

Ibrahim²,

Ng³

et al. 2021

Digital Encyclopedia of Applied Physics

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This article is designed to help readers understand some typical wavefront detection techniques and gain a preliminary understanding of wavefront detection. In this tutorial, the wavefront definition used in wavefront technology is given and we divide wavefront detection technologies into qualitative and quantitative categories. In each category, we discuss some typical systems and provide simulation results. This tutorial comes with Matlab simulation codes that readers can use to simulate mentioned wavefront detection technologies on their computers. We hope that this tutorial provides readers with all the tools needed to understand and simulate the different wavefront technologies and modify them based on their needs and interest.

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Measurement of temperature and velocity fields in a convective fluid flow in air using schlieren images

Cited by 28 publications

References 22 publications

Cavitation clusters in lipid systems – surface effects, local heating and streamer formation

Cavitation clusters in lipid systems – surface effects, local heating and streamer formation

Using Infrared Laser Absorption to Measure Hydrocarbon Concentration in a Lean-Burn, Stratified-Charge, Spark-Ignition Engine

Optical Wavefront Detection: A Beginner Tutorial

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