<p>狭长空间广泛存在于矿山、交通、市政等工程中。一旦发生火灾，高温烟气在较短时间内即可充满空间，能见度大幅降低，逃生路径单一且疏散困难。水作为主要灭火手段存在易流失的不足，灭火效率低，加入胶体灭火剂增加黏附性，能够延长冷却时间提升灭火效率。本文研究狭长空间木垛火源燃烧行为及温度场动态演化规律，研发高分子胶体及对狭长空间木垛火的抑制效能，揭示高分子胶体抑制狭长空间木材火的作用机制，对提升狭长空间火场控制能力具有重要的理论和现实意义。主要研究内容及成果如下：</p> <p>（1）依据Froude相似准则设计了1:10缩尺寸狭长空间火灾实验台，研究了不同空隙度木垛在六种风速条件下的燃烧特性和空间温度分布特征，确定了将烟气控制在上游0.8 m附近的约束风速。自然通风下，火焰竖直向上，氧气浓度谷值与一氧化碳浓度峰值同时出现，氧气供应不足导致木垛不充分燃烧。纵向通风条件下木垛火势发展速率增加5倍，热释放速率峰值增至1.5~1.7倍。建立了顶棚纵向温升分布预测模型和截面平均温度计算模型。</p> <p>（2）采用羟丙基甲基纤维素、十二烷基硫酸钠、高吸水树脂、聚磷酸铵和氢氧化铝复配高分子胶体，凝胶温度为32 ℃，升温后具有迅速凝胶化和黏弹性强的特点。建立不同质量分数高分子胶体流变方程，分析动态润湿性能，当质量分数为8%时，高分子胶体易于铺展润湿木材表面。研究了高分子胶体对木材热解过程中吸放热特性的影响，升温过程中木材吸热焓值增加，放热焓值降低。</p> <p>（3）开展了高分子胶体喷淋抑燃实验，研究了高分子胶体对木垛燃烧行为和狭长空间温度演化的影响规律。将喷淋抑制木垛火分为火焰压制、表面火熄灭和内部火熄灭三个阶段，喷淋压力与火源预燃时间是影响灭火有效性的主要参数。高分子胶体有利于缩短内部火熄灭时间，降低由灭火导致的一氧化碳增加量。喷淋高分子胶体时顶棚最高温度随时间推移呈指数衰减，顶棚温度最低点出现在木垛上游边界附近，火源下游附近截面高度10 cm~20 cm是发生烟气沉降的危险位置。基于实验数据建立二级指标体系，当喷淋压力0.6 MPa ~0.8 MPa时，高分子胶体抑制燃烧效率更高。</p> <p>（4）基于液滴与火焰的相互作用，分析了高分子胶体液滴在火场中蒸发、运动及木材表面的传热传质过程。结合表面铺展高分子胶体对木材燃烧的影响，揭示了喷淋高分子胶体抑制和熄灭木材火的主要机制。高分子胶体液滴动量压制并穿透火羽流，到达木材表面铺展形成隔热凝胶层，延迟木材的点燃时间；促进木材炭化，抑制纤维素和木质素热解，热释放速率降低；凝胶的热解气相产物稀释可燃气浓度并消耗火焰自由基，凝聚相产物形成致密炭层阻碍热质交换，总释热量降低，减少烟雾生成和有害气体释放。</p>

<p>Long and narrow spaces play an integral role in engineering applications, such as mining, transportation, and municipal projects. Once occurred a fire, high-temperature smoke can rapidly inundate the cross-section in a short period, substantially diminishing visibility. This situation poses a significant risk as the escape routes are limited and evacuation becomes challenging. Despite being a primary firefighting medium, water has a critical shortcoming of being easily lost due to runoff. Colloids enhance the effectiveness by increasing adhesion and prolonging the cooling time. This study investigated the combustion behavior and dynamic evolution of temperature fields in a long and narrow space with wood crib fire sources. A polymer colloid was developed and its suppressive efficiency against fires in these specific scenarios was analyzed. The suppression mechanism of the polymer colloid was also elucidated. These insights offer significant theoretical and practical value for enhancing fire management capabilities in such complicated environments. Highlighted below are the main research content and achievements:</p> <p>(1) A 1:10 scaled experimental setup for narrow and confined space fires was established according to the Froude similarity criterion. The combustion characteristics and temperature distribution features of wood cribs with various porosity types under six different ventilation conditions. Under natural ventilation, the flames predominantly rise vertically, with the lowest oxygen concentration and highest CO concentration occurring simultaneously. The insufficient oxygen supply led to incomplete combustion. In the cases of longitudinal ventilation, the fire growth rate of wood cribs increased by 5 times, and the peak heat release rate rose to 1.5 to 1.7 times. The predictive model of longitudinal ceiling temperature rise distribution and calculation model for cross-sectional average temperature have been established.</p> <p>(2) A thermal gelation polymer colloid has been developed with hydroxypropyl methyl cellulose, sodium dodecyl sulfate, superabsorbent resin, ammonium polyphosphate and aluminum hydroxide. The lower critical solution temperature was 32 ℃, exhibiting rapid gelation and strong viscoelastic properties depending on heating. Rheological equations for the polymeric colloid at different mass fractions were established and the dynamic wetting performance was analyzed. When added at a mass fraction of 8%, the polymer colloid was found to easily spread and wet the wood surface. The effect of polymer colloid on the heat absorption and release characteristics of wood was studied. As the temperature raises, the enthalpy of heat absorption increased, while the release enthalpy decreased.</p> <p>(3) Polymer colloid spray suppression experiments were conducted to investigate the influence on the combustion behavior and temperature evolution of wood crib fires in the long and narrow space. The process of fire suppression by spraying was divided into three stages: flame suppression, surface fire extinguishment, and internal fire extinguishment. The spraying pressure and wood pre-burn time were identified as the main parameters affecting the effectiveness of polymer colloid fire suppression. The polymer colloid was found to be beneficial in reducing the required time of internal fire extinguishment and the increasement of CO concentration caused by extinguishing. When spraying the polymer colloid, the maximum ceiling temperature exhibited exponential decay over time. The lowest point of ceiling temperature was observed near the upstream boundary of the wood cribs. Heights of 10 to 20 cm in the downstream vicinity of the fire source were considered as risky positions for smoke settlement. A secondary index system was constructed drawing from the experimental data to assess the efficiency of fire suppression. The polymer colloid demonstrated more superior performance with the spray pressure in the range of 0.6 to 0.8 MPa.</p> <p>(4) Relying on the interplay between droplets and flames, the processes of evaporation, movement, and heat and mass transfer of polymeric colloid droplets on the wood surface in a fire scenario were investigated. Coupled with the impact of polymeric colloid on wood combustion and pyrolysis, the fundamental suppression mechanisms of the polymeric colloid spray on wood fires were brought to light. The momentum of polymer colloid droplets suppressed the flame front and penetrated the fire plume, reaching the wood surface and spreading to form a heat-insulating gel layer, which delayed the ignition time. It also promoted wood carbonization, inhibited the pyrolysis of cellulose and lignin, and resulted in decreases in both the rate and total quantity of heat release. Gaseous products from the gel decomposition diluted flammable gas concentration and consumed flame radicals. Meanwhile, the condensed phase products formed a dense char layer, hindering heat and mass exchange and reducing smoke generation and harmful gases release.</p>