Canjun Liang

Bio: Canjun Liang is an academic researcher from University of Science and Technology of China. The author has contributed to research in topics: Fire protection & Heat flux. The author has an hindex of 2, co-authored 2 publications receiving 20 citations. Previous affiliations of Canjun Liang include City University of Hong Kong.

Experimental study of vertically upward flame spread over polymethyl methacrylate slabs at different altitudes

Abstract: Summary Experiments of vertically upward flame spread over polymethyl methacrylate slabs were conducted in Hefei (with an altitude of 29.8 m) and Lhasa (with an altitude of 3658.0 m). Measurements were taken for the flame heights, the flame heat flux to the fuel surface and the flame spread rate. Two regions were identified for the dependence of the flame height on the heat release rate per unit width . When is less than 22 kW/m, the flame height scales as while it scales as , when is greater than 22 kW/m. The flame heights in Lhasa are approximately 1.34 and 1.25 times, respectively, of those in Hefei for these two regions. The flame heat flux to the fuel surface decreases significantly from the pyrolysis front to the flame tip, whereas it decreases slowly above the flame tip. In both regions, it can be correlated reasonably well with (x − xp)/(xf − xp) using the form of . The flame heat flux to the fuel surface in Lhasa is approximately 0.75 times of that in Hefei. The flame spread process can be divided into three stages, which correspond to a flow region of laminar, transitional, and turbulent, respectively. The transition to a turbulent flow is delayed in Lhasa compared with Hefei. The flame spread rate in Lhasa is about half of that in Hefei because of the lower flame heat flux caused by the lower ambient pressure. Copyright © 2015 John Wiley & Sons, Ltd.

Improving the performance of fluoroprotein foam in extinguishing gasoline pool fires with addition of bromofluoropropene

Abstract: SUMMARY The fluoroprotein foam is one of the most widely used fire suppressants for its low cost, low toxicity and biodegradability. However, its fire extinguishing performance is limited. In this article, fluoroprotein foam was combined with a clean and degradable fire suppressant of 2-bromo-3,3,3-trifluoropropene (BTP) to improve its fire extinguishing efficiency. Laboratory scale suppression experiments on gasoline pool fires were conducted in a 27 m3 confined space. An optimized volume flow ratio of air to foam solution was found out first to acquire fluoroprotein foam with best fire extinguishing efficiency; then varied amounts of BTP were added to the foam at the optimal flow ratio for performance examination. Results demonstrated: at the optimized volume flow ratio of air to foam solution of 9 and the volume flow ratio of BTP to foam solution of 3.75%, a superior fire extinguishing performance was achieved with the fire extinguishing time reduced by 43% in comparison to that without any BTP added. The fire suppression mechanism of the foam with BTP additive was discussed based on established fire suppression theories and experimental results. Copyright © 2014 John Wiley & Sons, Ltd.

Experimental Analysis of Critical Acceleration Condition for Two-Sided Upward Flame Spread Over Inclined Thin Fuel Surfaces

Abstract: Most of previous work focused on the one-sided upward flame spread over inclined surfaces. However, few investigations have systematically addressed the dependence of spread rate on the inclination angle for two-sided upward flame spreading. The present paper investigates the two-sided upward flame behaviors over inclined surfaces by performing experiments using 0.255 mm thick, 100 cm tall and 5 cm wide cotton sample sheets with various inclination angles varying 0° to 90° from the horizontal. The pyrolysis spread rate, pyrolysis length, preheating length, ignition time, flame tilt angle and standoff distance are obtained and analyzed. The corresponding results are as follows: As the inclination angle increases, the pyrolysis spread rate, pyrolysis length and preheating length increase, but the ignition time decreases. One transition zone is observed around 10° to 15° for flame spread rate, pyrolysis length and preheating length, which is an external manifestation of the change of flame spread from steady state to acceleration. Two parameters of tilt angle and standoff distance are used to qualitatively modify the heat flux profiles ahead of the flame front, which control the flame spread rate. Generally, the tilt angle and standoff distance of upper flame decrease as a function of inclination angle. On the contrary, the standoff distance shows an opposite trend with inclination angle. The combined effects of radiation and convection of upper and lower flames result in a sharp increase in net heat flux, and correspondingly a transition zone occurs around 10° to 15°. The results of this study have implications concerning designs for fire safety and may help advance understanding of two-sided flame spread over inclined surfaces.