Cellular flame structures and thermal characteristics of axi-symmetric ceiling fires: An experimental study and scaling analysis

It is well known that attaching fins on the tubes surfaces can enhance the heat transfer into and out from the phase change materials (PCMs). This paper presents the results of an experimental study on the thermal characteristics of finned coil latent heat storage unit (LHSU) using paraffin as the phase change material (PCM). The paraffin LHSU is a rectangular cube consists of continuous horizontal multibended tubes attached vertical fins at the pitches of 2.5, 5.0, and 7.5 mm that creates the heat transfer surface. The shell side along with the space around the tubes and fins is filled with the material RT54 allocated to store energy of water, which flows inside the tubes as heat transfer fluid (HTF). The measurement is carried out under four different water flow rates: 1.01, 1.30, 1.50, and 1.70 L/min in the charging and discharging process, respectively. The temperature of paraffin and water, charging and discharging wattage, and heat transfer coefficient are plotted in relation to the working time and water flow rate.

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Preparation and experimental study on the thermal characteristics of lightweight prefabricated nano-silica aerogel foam concrete wallboards

Construction and Building Materials ◽

10.1016/j.conbuildmat.2020.121895 ◽

2021 ◽

Vol 272 ◽

pp. 121895

Author(s):

Peng Liu ◽

Yan Feng Gong ◽

Guo Hua Tian ◽

Zheng Kun Miao

Keyword(s):

Experimental Study ◽

Silica Aerogel ◽

Thermal Characteristics ◽

Nano Silica ◽

Foam Concrete

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Experimental Study on Thermal Characteristics of DC Arc Formation between Ice-Electrode Gap

IEEE Transactions on Dielectrics and Electrical Insulation ◽

10.1109/tdei.2021.009546 ◽

2021 ◽

Vol 28 (5) ◽

pp. 1497-1505

Author(s):

Meng Wei ◽

Jianlin Hu ◽

Xiaofeng Wang ◽

Xingliang Jiang ◽

Ruihe Zhang ◽

...

Keyword(s):

Experimental Study ◽

Thermal Characteristics ◽

Electrode Gap ◽

Dc Arc

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Experimental study on thermal characteristics of positive leader discharges using Mach-Zehnder interferometry

Physics of Plasmas ◽

10.1063/1.4922660 ◽

2015 ◽

Vol 22 (6) ◽

pp. 063508 ◽

Cited By ~ 8

Author(s):

X. Zhou ◽

R. Zeng ◽

C. Zhuang ◽

S. Chen

Keyword(s):

Experimental Study ◽

Thermal Characteristics

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Role of Darrieus–Landau instability in propagation of expanding turbulent flames

Journal of Fluid Mechanics ◽

10.1017/jfm.2018.426 ◽

2018 ◽

Vol 850 ◽

pp. 784-802 ◽

Cited By ~ 15

Author(s):

Sheng Yang ◽

Abhishek Saha ◽

Zirui Liu ◽

Chung K. Law

Keyword(s):

Flame Front ◽

Flame Propagation ◽

High Pressures ◽

Turbulent Flame ◽

Turbulent Flames ◽

Scaling Analysis ◽

Turbulent Eddies ◽

Front Instability ◽

Cellular Flame

In this paper we study the essential role of Darrieus–Landau (DL), hydrodynamic, cellular flame-front instability in the propagation of expanding turbulent flames. First, we analyse and compare the characteristic time scales of flame wrinkling under the simultaneous actions of DL instability and turbulent eddies, based on which three turbulent flame propagation regimes are identified, namely, instability dominated, instability–turbulence interaction and turbulence dominated regimes. We then perform experiments over an extensive range of conditions, including high pressures, to promote and manipulate the DL instability. The results clearly demonstrate the increase in the acceleration exponent of the turbulent flame propagation as these three regimes are traversed from the weakest to the strongest, which are respectively similar to those of the laminar cellularly unstable flame and the turbulent flame without flame-front instability, and thus validating the scaling analysis. Finally, based on the scaling analysis and the experimental results, we propose a modification of the conventional turbulent flame regime diagram to account for the effects of DL instability.

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