Experimental Study of Thermal Behavior of Insulation Material Rigid Polyurethane in Parallel, Symmetric, and Adjacent Building Façade Constructions
Abstract
:1. Introduction
2. Materials and Methods
3. Results and Discussion
3.1. Flame morphology and Spreading Behavior
3.2. Overall Comparison of Burning Rates
3.3. Flame Height and Flame Front Variations
3.4. Flame Spreading Rates
4. Conclusions
- The parallel symmetric flame leading edge front was observed to change from one-dimensional to a unique morphology with an inverted ‘W’ shape, and finally exhibited an inverted ‘V’ shape. This occurred in conjunction with a narrow sample width due to the edge effect and the shear force that supplied additional heat feedback with enriched oxygen diffusion. The angle of the inverted ‘V’ shape was found to decrease as the flame spreading progressed.
- As the adjacent façade angle decreased, the burning rate varied in a nonlinear manner. This is attributed to the competition between the negative and positive effects of the parallel adjacent façade configuration. The downward flame spreading over the PUR was essentially stable during the early stage of flame spreading while accelerated flame spreading was observed during the later period. Phenomenological two-pass processing of the mass loss data showed complex combustion behavior that could complicate fire rescue.
- The average flame spreading rate and flame height both initially increased and then decreased with increases in the adjacent angle, similar to the trend displayed by the burning rate data. A critical angle of approximately was identified, due to the combined chimney and restriction effects induced by changes in the adjacent façade configuration. At smaller angles ( to ), the radiative heat transfer increased as a result of increases in the heat transfer from the opposite flame and the weakened chimney effect. At larger angles, the radiative heat transfer from the opposite flame and ember was gradually decreased, resulting in a lower flame spreading rate.
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
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Tested Material | Density (kg/m3) | Heat Capacity (J/kg·K) | Thermal Conductivity coefficient (W/m·K) | Pyrolysis Temperature (K) | Heat of Combustion (MJ/kg) |
---|---|---|---|---|---|
PUR | 60 | 1300 | 0.03 | 470 | 27 |
Percentage (%) | 60° | 90° | 120° | 150° | 180° |
34.10% | 31.78% | 33.20% | 40.48% | 51.52% |
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Ma, X.; Tu, R.; Cheng, X.; Zhu, S.; Ma, J.; Fang, T. Experimental Study of Thermal Behavior of Insulation Material Rigid Polyurethane in Parallel, Symmetric, and Adjacent Building Façade Constructions. Polymers 2018, 10, 1104. https://doi.org/10.3390/polym10101104
Ma X, Tu R, Cheng X, Zhu S, Ma J, Fang T. Experimental Study of Thermal Behavior of Insulation Material Rigid Polyurethane in Parallel, Symmetric, and Adjacent Building Façade Constructions. Polymers. 2018; 10(10):1104. https://doi.org/10.3390/polym10101104
Chicago/Turabian StyleMa, Xin, Ran Tu, Xudong Cheng, Shuguang Zhu, Jinwei Ma, and Tingyong Fang. 2018. "Experimental Study of Thermal Behavior of Insulation Material Rigid Polyurethane in Parallel, Symmetric, and Adjacent Building Façade Constructions" Polymers 10, no. 10: 1104. https://doi.org/10.3390/polym10101104