Temperature measurement of an axisymmetric flame by using a schlieren system

Alvarez-Herrera, C.; Moreno-Hernández, D.; Barrientos-García, Bernardino

doi:10.1088/1464-4258/10/10/104014

Cited by 30 publications

(8 citation statements)

References 20 publications

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“…In this simple diagram a light ray refracted upward (dashed line) avoids the knife-edge and proceeds to the camera, while another refracted downward (solid line) was blocked by the knife-edge. Generalizing this to every ray in the light beam, we had an instrument that captures a pure phase disturbance S as a grayscale amplitude image in the camera [5,12].…”

Section: Experimental Setupsmentioning

confidence: 99%

Relaxation process of the discharge channel near the anode in long air gaps under positive impulse voltages

Zhao¹,

He²,

Luo³

et al. 2017

J. Phys. D: Appl. Phys.

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The relaxation process of the discharge channel near the anode in a long air gap was observed using a Schlieren system with a temporal resolution of 5 µs and a spatial resolution of 70 µm. The dynamic characteristics of the decay process in the vicinity of the anode are obtained. The discharge channel evolves just as a growing mushroom in nature during the relaxation phase. Two physical quantities, angle θ and velocity v, are defined to describe the process in this paper. The average value of the angle and velocity under lightning impulses are 71.7° and 3.3 m s −1 respectively, while 7.7 m s −1 under switching impulses. A simplified model was established to simulate the formation of mushroom-shaped channel. The simulation and experimental results show that the formation and development of the mushroom-shaped channel are due to two factors. One is the convection of the high temperature and high pressure air near the anode produced by the first corona discharge; the other is the ionic migration. These two factors result in the phenomena that the cooling process in the vicinity of the anode is much more efficient than further into the gap, whereas the thermal conductivity of the anode may have little contribution to that.

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Section: Experimental Setupsmentioning

confidence: 99%

Relaxation process of the discharge channel near the anode in long air gaps under positive impulse voltages

Zhao¹,

He²,

Luo³

et al. 2017

J. Phys. D: Appl. Phys.

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“…The camera provides 30 frames per second with 640 x 640 pixels. The burner was located in the middle of the schlieren set-up and the hot gases produced by the combustion flame flow in vertical direction, the same direction in which is positioned the knife edge so the schlieren set-up can be sensible in the x direction [13].…”

Section: D Reconstruction Of Flamementioning

confidence: 99%

3D flame reconstruction and error calculation from a schlieren projection

Alvarez-Herrera

Herrera-Aguilar

Moreno-Hernández

et al. 2020

J. Eur. Opt. Soc.-Rapid Publ.

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In this work a 3D flame reconstruction is performed from a 2D projection of the hot gases of a combustion flame. The projection is obtained using an optical schlieren technique. In this technique, a schlieren image is integrated linearly to obtain the hot gases, and then, a temperature field. Each row of the matrix representing the temperature distribution is fitted with a specific function, and its respective error is calculated. In this way, the projected matrix can be represented with the fitted functions. As a result of the procedure used in this research, a slice of the flame is obtained by assuming a cylindrical symmetry of it and multiplying the fitted function by itself. Finally, it was evaluated the mean error in calculations of temperature intensity in the flame under the cylindrical symmetry assumption obtaining an accuracy of 96% which validates the efficiency of our method.

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“…The POD method provides the most efficient way of capturing the dominant features of an infinite-dimensional process with only a few functions. In this approach a set of optimized orthonormal basic functions for an ensemble of data are supplied [6,17,18,20].…”

Section: Pod Theorymentioning

confidence: 99%

Proper orthogonal decomposition applied to laminar thermal convection in a vertical two plate channel

Alvarez-Herrera

Murillo-Ramírez

Pérez-Reyes

et al. 2015

J. Opt.

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This work reports the thermal convection with imposed shear flow in a thin two-plate channel. Flow structures are investigated under heating asymmetric conditions and different laminar flow conditions. The dynamics of heat flow and the energy distribution were determined by visualization with the Schlieren technique and application of the proper orthogonal decomposition (POD) method. The obtained results from the POD mode analysis revealed that for some flow conditions the heat transfer is related to the energy of the POD modes and their characteristic numbers. It was possible to detect periodic motion in the two-plate channel flow from the POD mode analysis. It was also found that when the energy is distributed among many POD modes, the fluid flow is disorganized and unsteady. Keywords: Schlieren devices, image forming and processing, channel and internal heat flow, laminar flows in cavities channels ducts and conduits

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Temperature measurement of an axisymmetric flame by using a schlieren system

Cited by 30 publications

References 20 publications

Relaxation process of the discharge channel near the anode in long air gaps under positive impulse voltages

Relaxation process of the discharge channel near the anode in long air gaps under positive impulse voltages

3D flame reconstruction and error calculation from a schlieren projection

Proper orthogonal decomposition applied to laminar thermal convection in a vertical two plate channel

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