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Your search keyword '"Dai, Jiakun"' showing total 3 results
Start Over Author "Dai, Jiakun" Topic pyrolysis
3 results on '"Dai, Jiakun"'

1. Experiment study of the altitude effects on spontaneous ignition characteristics of wood

Author

Deng Zhihua, Dai Jiakun, Zhou Xiaodong, Yang Lizhong, Wang Yafei, and Zhou Yupeng

Subjects
Chemistry, General Chemical Engineering, Organic Chemistry, Energy Engineering and Power Technology, Mineralogy, Autoignition temperature, Effects of high altitude on humans, Atmospheric sciences, law.invention, Ignition system, Fuel Technology, Altitude, Physics::Plasma Physics, law, Slab, Physics::Chemical Physics, Pyrolysis, Spontaneous combustion, Ambient pressure
Abstract

This paper has studied the influence of ambient pressure and oxygen content on spontaneous ignition of wood by conducting contrastive experiments with wood slab exposed to high temperature radiation at two different altitudes. The measurement of mass loss, time to ignition, and surface temperature of wood are carried out. Results show that mass loss rate of wood at high altitudes (3650 m) is higher than the one at low altitudes (50 m), while ignition delay time of the sample at high altitude is shorter. The surface temperatures at the time of ignition in the two different places are both close to each other, which indicates that the pressure did not affects the ignition temperature. The theoretical analysis on the phenomenon of different ignition behavior of wood in these two altitude environments has been presented.

Published
2010

2. Autoignition of solid combustibles subjected to a uniform incident heat flux: The effect of distance from the radiation source

Author

Dai Jiakun, Wang Yafei, Zhou Yupeng, Deng Zhihua, Zhou Xiaodong, and Yang Lizhong

Subjects
Mass flux, Chemistry, General Chemical Engineering, General Physics and Astronomy, Energy Engineering and Power Technology, Thermodynamics, Autoignition temperature, General Chemistry, Radiation, law.invention, Ignition system, Fuel Technology, Radiant heating, Heat flux, law, Physics::Chemical Physics, Pyrolysis, Dimensionless quantity
Abstract

The ignitability of solid combustibles by a radiation source has been investigated experimentally as a function of distance between the solid and the source, for heating with a uniform incident heat flux. Unlike piloted ignition, the critical incident heat flux for autoignition increases with the increase of radiant distance, which is a result that has not been reported before. It is found that the generation rate of combustible pyrolysis volatiles is a necessary but not sufficient condition for autoignition. By two dimensionless parameters, it is clearly indicated that the occurrence of autoignition needs both sufficient gas-phase temperature and sufficient concentration of combustible pyrolysis volatiles simultaneously, especially for the larger radiant heating distance condition which is also closer to realistic fire conditions.

Published
2011

3. Piloted ignition and extinction for solid fuels.

Author

Dai, Jiakun, Delichatsios, Michael A., Yang, Lizhong, and Zhang, Jianping

Subjects
CHEMICAL reactions, FUEL cells, TEMPERATURE effect, PYROLYSIS, TEMPERATURE measurements, METHANE, GAS phase reactions
Abstract

Abstract: Piloted ignition of solid fuels is investigated by simulating the transport and chemical reaction in a counter-flow arrangement where a known fuel (methane) is supplied through a porous burner and the power and the location of the igniter are varied. The porous burner arrangement simulates a pyrolyzing solid fuel at constant temperature by separating the gas phase from the solid conduction and pyrolysis phenomena. An Arrhenius one-step global reaction and a simplified transport model with Lewis number equal to one were used in the simulation. Only quasi-steady conditions are considered for the gas phase in this work because the response time for the solid phenomena is, in general, much larger than the response diffusion time for the gaseous phenomena. The relation of piloted ignition to extinction is also investigated. The effect of Damköhler number on ignition and extinction and the effect of the igniter on ignition are presented through a characteristic S curve obtained by plotting the evolving maximum temperature as a function of fuel mass flux. Based on the S-shaped curve (representing the maximum temperature in the system versus the mass flux of fuel), the relationship between the piloted ignition and extinction turning points and mass fluxes has been demonstrated in this paper. The piloted ignition turning point gradually approaches the extinction turning point with increasing Damköhler number and also with increasing power of the igniter. The ignition mass flux is found to depend basically on three parameters, Damköhler number, the location of the igniter and the power of the igniter all expressed in dimensionless forms. [Copyright &y& Elsevier]

Published
2013
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