scholarly journals A study on burning behavior and convective flows in Methanol pool fires bound by ice

2017 ◽  
Vol 2017 (1) ◽  
pp. 1983-1998 ◽  
Author(s):  
Hamed Farmahini Farahani ◽  
Grunde Jomaas ◽  
Ali S. Rangwala
Keyword(s):  
Liquid Phase ◽  
Flow Field ◽  
Particle Image Velocimetry System ◽  
Pool Fires ◽  
Convective Flows ◽  
Burning Behavior ◽  
Image Velocimetry ◽  
Lateral Cavity ◽  
Burning Rates ◽  
Burning Parameters

Abstract (ID: 2017-170) An experimental study on methanol pool fires bound by ice was carried to research the burning behavior and flow field (within the liquid-phase) of methanol. The experiments were conducted in two parts: 1- in a cylindrical ice cavity/pan (10.2 cm diameter and 6 cm depth) at three different conditions to analyze burning parameters of methanol, 2- in a square glass tray with outside dimensions of 10 × 10 cm and a depth of 5 cm to obtain flow field of methanol pool with a two-dimensional PIV (Particle Image Velocimetry) system. The results of the experiments of the first part show the cold boundaries of the ice cavity/pan act as a heat sink causing considerable heat losses. Thus, burning rates and burning efficiencies are found to be lower with cold boundaries. However, the burning rate values in ice cavity are found to be the highest because of the melting of the ice and expansion of the cavity. The analysis of the results obtained by the PIV system showed the velocity magnitudes and flow patterns in the liquid-phase of icy methanol fire significantly change over the course of burning. In the instants after ignition a horizontal flow induced by Marangoni near the surface was observed. Later on, mixing of melt-water with methanol and sinking of this mixture caused a cycle in the tray that resulted in a vortex appearing in the middle of the pool. Magnitudes of velocity were also observed to increase after ignition. The increase in the velocity magnitudes is expected to significantly impact the melting and size of the lateral cavity.

Particle image velocimetry investigation on air distribution of surface-source buoyancy plume changing heating intensity and structure size in a thermostatic chamber

2020 ◽  
pp. 1420326X2092624
Author(s):  
Xin Wang ◽  
Yukun Xu ◽  
Yinchen Yang ◽  
Bingyan Song
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Axial Velocity ◽  
Particle Image ◽  
Source Parameters ◽  
Air Distribution ◽  
Particle Image Velocimetry System ◽  
Surface Source ◽  
Large Space ◽  
Image Velocimetry

For large space buildings like industrial plants with huge heat generation, the role that surface-source plumes play becomes more crucial. To study the air distribution and movement of plumes, the first step is to quantify how the airflow gets distributed in chambers. The experiment was carried out in a thermostatic chamber where there was no ventilation. Four hundred flow field snapshots (in each region) were measured by a two-dimensional particle image velocimetry system at a sampling frequency of 3 Hz, and the time-average flow field was processed by the adaptive correlation algorithm to quantify the air distribution of the plume. According to the measured data, the variation law of the axial velocity of the surface-source plume under different heat source parameters was analysed. The formula coefficients of the axial velocity, the extended radius and the mass flow of the plume were discussed, and the coefficients from current two mainstream methods and those obtained in this paper were compared. The results of this study will be useful to predict motion of surface-plumes and optimize airflow patterns in large spaces.

Flow Field Analysis of a Single Piezoelectric Fan

2009 ◽  
Author(s):  
Andrew Eastman ◽  
Mark Kimber
Keyword(s):  
Flow Field ◽  
Piezoelectric Material ◽  
Electronics Cooling ◽  
Three Dimensions ◽  
Field Analysis ◽  
Particle Image Velocimetry System ◽  
Starting Point ◽  
Image Velocimetry ◽  
Fan Blade ◽  
Common Application

Piezoelectrically actuated fans are relatively simple structures consisting of a piezoelectric material affixed to a thin cantilever beam. It is then subjected to a current that causes the beam to oscillate by the constriction and expansion of the piezoelectric material. A common application is that of electronics cooling where the induced flows can greatly augment natural or forced convection. Previous studies have sought to explore the flow field of piezoelectric fans in relation to its heat transfer application. This research seeks to expand upon that knowledge with a focus on measuring the flow parallel to the fan blade. A fan with length and width of 36.5 mm and 12.7 mm, respectively, is excited with an oscillating voltage input of 62.5 Hz and varying amplitudes. A Particle Image Velocimetry system, able to chart particle movement in the x and y directions, is employed to aid in understanding the flow field created by the fan with an emphasis on studying the vortex shed by a single half period of oscillation. This information has the potential to be a starting point for further exploration into a dual fan application and how their interactions alter vortex shedding in both two and three dimensions.

Correlation of Burning Rates and Energy Transport Mechanisms in Open and Enclosed Liquid Pool Fires

1991 ◽  
Author(s):  
David E. Ramaker ◽  
K. C. Adiga ◽  
H. Zhang ◽  
M. Pivovarov ◽  
S. W. Baek
Keyword(s):  
Energy Transport ◽  
Liquid Pool ◽  
Pool Fires ◽  
Transport Mechanisms ◽  
Burning Rates

scholarly journals Influence of a Standing Wave Flow-Field on the Dynamics of a Spray Diffusion Flame

Fluids ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 27
Author(s):  
J. Barry Greenberg ◽  
David Katoshevski
Keyword(s):  
Liquid Phase ◽  
Flow Field ◽  
Standing Wave ◽  
Diffusion Flame ◽  
Stokes Number ◽  
Flame Height ◽  
Wave Flow ◽  
Two Dimensional ◽  
Governing Equations ◽  
First Time

A theoretical investigation of the influence of a standing wave flow-field on the dynamics of a laminar two-dimensional spray diffusion flame is presented for the first time. The mathematical analysis permits mild slip between the droplets and their host surroundings. For the liquid phase, the use of a small Stokes number as the perturbation parameater enables a solution of the governing equations to be developed. Influence of the standing wave flow-field on droplet grouping is described by a specially constructed modification of the vaporization Damkohler number. Instantaneous flame front shapes are found via a solution for the usual Schwab–Zeldovitch parameter. Numerical results obtained from the analytical solution uncover the strong bearing that droplet grouping, induced by the standing wave flow-field, can have on flame height, shape, and type (over- or under-ventilated) and on the existence of multiple flame fronts.

Endoscopic 2D particle image velocimetry (PIV) flow field measurements in IC engines

2002 ◽  
Vol 33 (6) ◽  
pp. 794-800 ◽  
Author(s):  
U. Dierksheide ◽  
P. Meyer ◽  
T. Hovestadt ◽  
W. Hentschel
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Particle Image ◽  
Field Measurements ◽  
Image Velocimetry ◽  
Ic Engines

scholarly journals Manifold reduction techniques for the comparison of crank angle-resolved particle image velocimetry (PIV) data and Reynolds-averaged Navier-Stokes (RANS) simulations in a spark ignition direct injection (SIDI) engine

2021 ◽  
pp. 146808742110131
Author(s):  
Xiaohang Fang ◽  
Li Shen ◽  
Christopher Willman ◽  
Rachel Magnanon ◽  
Giuseppe Virelli ◽  
...  
Keyword(s):  
Flow Field ◽  
Particle Image ◽  
Direct Injection ◽  
Linear Manifold ◽  
Main Flow ◽  
Navier Stokes ◽  
Reduction Techniques ◽  
Image Velocimetry ◽  
Manifold Reduction ◽  
Relevance Index

In this article, different manifold reduction techniques are implemented for the post-processing of Particle Image Velocimetry (PIV) images from a Spark Ignition Direct Injection (SIDI) engine. The methods are proposed to help make a more objective comparison between Reynolds-averaged Navier-Stokes (RANS) simulations and PIV experiments when Cycle-to-Cycle Variations (CCV) are present in the flow field. The two different methods used here are based on Singular Value Decomposition (SVD) principles where Proper Orthogonal Decomposition (POD) and Kernel Principal Component Analysis (KPCA) are used for representing linear and non-linear manifold reduction techniques. To the authors’ best knowledge, this is the first time a non-linear manifold reduction technique, such as KPCA, has ever been used in the study of in-cylinder flow fields. Both qualitative and quantitative studies are given to show the capability of each method in validating the simulation and incorporating CCV for each engine cycle. Traditional Relevance Index (RI) and two other previously developed novel indexes: the Weighted Relevance Index (WRI) and the Weighted Magnitude Index (WMI), are used for the quantitative study. The results indicate that both POD and KPCA show improvements in capturing the main flow field features compared to ensemble-averaged PIV experimental data and single cycle experimental flow fields while capturing CCV. Both methods present similar quantitative accuracy when using the three indexes. However, challenges were highlighted in the POD method for the selection of the number of POD modes needed for a representative reconstruction. When the flow field region presents a Gaussian distribution, the KPCA method is seen to provide a more objective numerical process as the reconstructed flow field will see convergence with an increasing number of modes due to its usage of Gaussian properties. No additional criterion is needed to determine how to reconstruct the main flow field feature. Using KPCA can, therefore, reduce the amount of analysis needed in the process of extracting the main flow field while incorporating CCV.

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