High Momentum Jet Flames at Elevated Pressure: Detailed Investigation of Flame Stabilization With Simultaneous Particle Image Velocimetry and OH-LIF

A model FLOX® combustor, featuring a single high momentum premixed jet flame, has been investigated using laser diagnostics in an optically accessible combustion chamber at a pressure of 8 bar. The model combustor was designed as a large single eccentric nozzle main burner (Ø 40 mm) together with an adjoining pilot burner and was operated with natural gas. To gain insight into the flame stabilization mechanisms with and without piloting, simultaneous particle image velocimetry (PIV) and OH laser-induced fluorescence (LIF) measurements have been performed at numerous two-dimensional (2D) sections of the flame. Additional OH-LIF measurements without PIV particles were analyzed quantitatively resulting in absolute OH concentrations and temperature fields. The flow field looks rather similar for both the unpiloted and the piloted cases, featuring a large recirculation zone next to the high momentum jet. However, flame shape and position change drastically. For the unpiloted case, the flame is lifted and widely distributed. Isolated flame kernels are found at the flame root in the vicinity of small-scale vortices. For the piloted flame, on the other hand, both pilot and main flame are attached to the burner base plate, and flame stabilization seems to take place on much smaller spatial scales with a connected flame front and no isolated flame kernels. The single-shot analysis gives rise to the assumption that for the unpiloted case, small-scale vortices act like the pilot burner flow in the opposed case and constantly impinge and ignite the high momentum jet at its root.

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High Momentum Jet Flames at Elevated Pressure: B — Detailed Investigation of Flame Stabilization With Simultaneous PIV and OH-LIF

Volume 4B: Combustion, Fuels and Emissions ◽

10.1115/gt2017-64556 ◽

2017 ◽

Cited By ~ 4

Author(s):

Michael Severin ◽

Oliver Lammel ◽

Holger Ax ◽

Rainer Lückerath ◽

Wolfgang Meier ◽

...

Keyword(s):

Laser Diagnostics ◽

Spatial Scales ◽

Flame Stabilization ◽

Temperature Fields ◽

Small Scale ◽

Single Shot ◽

High Momentum ◽

Position Change ◽

Jet Flame ◽

Pilot Burner

A model FLOX® combustor, featuring a single high momentum premixed jet flame, has been investigated using laser diagnostics in an optically accessible combustion chamber at a pressure of 8 bar. The model combustor was designed as a large single eccentric nozzle main burner (Ø 40 mm) together with an adjoining pilot burner and was operated with natural gas. To gain insight into the flame stabilization mechanisms with and without piloting, simultaneous Particle Image Velocimetry (PIV) and OH Laser Induced Fluorescence (LIF) measurements have been performed at numerous two-dimensional sections of the flame. Additional OH-LIF measurements without PIV-particles were analyzed quantitatively resulting in absolute OH concentrations and temperature fields. The flow field looks rather similar for both the unpiloted and the piloted case, featuring a large recirculation zone next to the high momentum jet. However, flame shape and position change drastically. For the unpiloted case, the flame is lifted, widely distributed and isolated flame kernels are found at the flame root in the vicinity of small scale vortices. For the piloted flame, on the other hand, both pilot and main flame are attached to the burner base plate, and flame stabilization seems to take place on much smaller spatial scales with a connected flame front and no isolated flame kernels. The single shot analysis gives rise to the assumption that for the unpiloted case small scale vortices act like the pilot burner flow in the opposed case and constantly impinge and ignite the high momentum jet at its root.

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Abstract 14952: Volumetric Echocardiographic Particle Image Velocimetry (V-Echo-PIV)

Circulation ◽

10.1161/circ.130.suppl_2.14952 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

Ahmad Falahatpisheh ◽

Arash Kheradvar

Keyword(s):

Particle Image Velocimetry ◽

Particle Image ◽

Contrast Echocardiography ◽

Ultrasound Contrast Agent ◽

Three Dimensions ◽

Small Scale ◽

High Temporal Resolution ◽

Two Dimensional ◽

Particle Image Velocimetry Technique ◽

Image Velocimetry

Introduction: The two-dimensional (2D) echocardiographic particle image velocimetry technique that was introduced in 2010 received much attention in clinical cardiology. Cardiac flow visualization based on contrast echocardiography results in images with high temporal resolution that are obtainable at relatively low cost. This makes it an ideal diagnostic and follow-up tool for routine clinical use. However, cardiac flow in a cardiac cycle is multidirectional with a tendency to spin in three dimensions rather than two-dimensional curl. Here, for the first time, we introduce a volumetric echocardiographic particle image velocimetry technique that robustly acquires the flow in three spatial dimensions and in time: Volumetric Echocardiographic Particle Image Velocimetry (V-Echo-PIV). Methods: V-Echo-PIV technique utilizes matrix array 3D ultrasound probes to capture the flow seeded with an ultrasound contrast agent (Definity). For this feasibility study, we used a pulse duplicator with a silicone ventricular sac along with bioprosthetic heart valves at the inlet and outlet. GE Vivid E9 system with an Active Matrix 4D Volume Phased Array probe at 30 Hz was used to capture the flow data (Figure 1). Results: The 3D particle field was obtained with excellent spatial resolution without significant noise (Figure 1). 3D velocity field was successfully captured for multiple cardiac cycles. Flow features are shown in Figure 2 where the velocity vectors in two selected slices and some streamlines in 3D space are depicted. Conclusions: We report successful completion of the feasibility studies for volumetric echocardiographic PIV in an LV phantom. The small-scale features of flow in the LV phantom were revealed by this technique. Validation and human studies are currently in progress.

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Experiments on wave propagation in grease ice: combined wave gauges and particle image velocimetry measurements

Journal of Fluid Mechanics ◽

10.1017/jfm.2019.16 ◽

2019 ◽

Vol 864 ◽

pp. 876-898 ◽

Cited By ~ 19

Author(s):

Jean Rabault ◽

Graig Sutherland ◽

Atle Jensen ◽

Kai H. Christensen ◽

Aleksey Marchenko

Keyword(s):

Wave Propagation ◽

Particle Image Velocimetry ◽

Particle Image ◽

Wave Attenuation ◽

Laboratory Data ◽

Decomposition Analysis ◽

Small Scale ◽

Wave Tank ◽

Wave Elevation ◽

Image Velocimetry

Water wave attenuation by grease ice is a key mechanism for the polar regions, as waves in ice influence many phenomena such as ice drift, ice breaking and ice formation. However, the models presented so far in the literature are limited in a number of regards, and more insights are required from either laboratory experiments or fieldwork for these models to be validated and improved. Unfortunately, performing detailed measurements of wave propagation in grease ice, either in the field or in the laboratory, is challenging. As a consequence, laboratory data are relatively scarce, and often consist of only a couple of wave elevation measurements along the length of the wave tank. We present combined measurements of wave elevation using an array of ultrasonic probes, and water kinematics using particle image velocimetry (PIV), in a small-scale wave tank experiment. Experiments are performed over a wider frequency range than has been previously investigated. The wave elevation measurements are used to compute the wavenumber and exponential damping coefficient. In contrast to a previous study in grease ice, we find that the wavenumber is consistent with the mass loading model, i.e. it increases compared with the open water case. Wave attenuation is compared with a series of one-layer models, and we show that they satisfactorily describe the viscous damping occurring. PIV data are also consistent with exponential wave amplitude attenuation, and a proper orthogonal decomposition analysis reveals the existence of mean flows under the ice that are a consequence of the displacement and packing of the ice induced by the gradient in the wave-induced stress. Finally, we show that the dynamics of grease ice can generate eddy structures that inject eddy viscosity into the water under the grease ice, which would lead to enhanced mixing and participating in energy dissipation.

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Wave-in-Deck Impact Loads in Relation With Wave Kinematics

Volume 3A: Structures, Safety and Reliability ◽

10.1115/omae2017-61406 ◽

2017 ◽

Author(s):

Jule Scharnke ◽

Rene Lindeboom ◽

Bulent Duz

Keyword(s):

Particle Image Velocimetry ◽

Particle Image ◽

Impact Load ◽

Breaking Waves ◽

Offshore Structures ◽

Small Scale ◽

Impact Loads ◽

Piv Measurements ◽

Wave Kinematics ◽

Image Velocimetry

Breaking waves have been studied for many decades and are still of interest as these waves contribute significantly to the dynamics and loading of offshore structures. In current MARIN research this awareness has led to the setup of an experiment to determine the kinematics of breaking waves using Particle Image Velocimetry (PIV). The purpose of the measurement campaign is to determine the evolution of the kinematics of breaking focussed waves. In addition to the PIV measurements in waves, small scale wave-in-deck impact load measurements on a fixed deck box were carried out in the same wave conditions. To investigate the link between wave kinematics and wave-in-deck impact loads, simplified loading models for estimating horizontal deck impact loads were applied and compared to the measured impact loads. In this paper, the comparison of the model test data to estimated loads is presented.

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Application of Particle Image Velocimetry to a Small-Scale de Laval Nozzle

AIAA Journal ◽

10.2514/2.7526 ◽

1999 ◽

Vol 37 (7) ◽

pp. 798-804 ◽

Cited By ~ 6

Author(s):

N. J. Lawson ◽

G. J. Page ◽

N. A. Halliwell ◽

J. M. Coupland

Keyword(s):

Particle Image Velocimetry ◽

Laval Nozzle ◽

Particle Image ◽

Small Scale ◽

Image Velocimetry ◽

De Laval Nozzle

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High Resolution Particle Image Velocimetry and CH-PLIF Measurements and Analysis of a Shear Layer Stabilized Flame

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4031367 ◽

2015 ◽

Vol 138 (3) ◽

Cited By ~ 5

Author(s):

C. W. Foley ◽

I. Chterev ◽

J. Seitzman ◽

T. Lieuwen

Keyword(s):

Particle Image Velocimetry ◽

High Resolution ◽

Shear Layer ◽

Flow Velocity ◽

Particle Image ◽

Flame Stabilization ◽

Flow Conditions ◽

Local Flow ◽

Image Velocimetry ◽

Flow Velocities

Understanding the mechanisms and physics of flame stabilization and blowoff of premixed flames is critical toward the design of high velocity combustion devices. In the high bulk flow velocity situation typical of practical combustors, the flame anchors in shear layers where the local flow velocities are much lower. Within the shear layer, fluid strain deformation rates are very high and the flame can be subjected to significant stretch levels. The main goal of this work was to characterize the flow and stretch conditions that a premixed flame experiences in a practical combustor geometry and to compare these values to calculated extinction values. High resolution, simultaneous particle image velocimetry (PIV) and planar laser induced fluorescence of CH radicals (CH-PLIF) measurements are used to capture the flame edge and near-field stabilization region. When approaching lean limit extinction conditions, we note characteristic changes in the stretch and flow conditions experienced by the flame. Most notably, the flame becomes less critically stretched when fuel/air ratio is decreased. However, at these lean conditions, the flame is subject to higher mean flow velocities at the edge, suggesting less favorable flow conditions are present at the attachment point of the flame as blowoff is approached. These measurements suggest that blowoff of the flame from the shear layer is not directly stretch extinction induced, but rather the result of an imbalance between the speed of the flame edge and local tangential flow velocity.

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