Modeling the trajectory of window flames with regard to flow attachment to the adjacent wall

A model for predicting the trajectory of window flame ejected from a fire compartment was formulated incorporating the effect of wall above the opening. Based on the observation in the reduced scale experiments, window flames were divided into the following categories with regard to its trajectory configuration: the flow which ascends almost vertically up after ejection maintaining a certain separation from the wall; and the flow which ascends upward after ejection and gradually approaches to the wall in the downstream. In the model, trajectories of these flows were approximated by cubic polynomials whose coefficients were given as functions of a dimensionless parameter F*. The parameter F* was derived from the conservation equation of momentum which incorporates the effect of pressure gradient across the ascending flows. Critical condition for the occurrence of flow attachment was described as a proportion of the maximum separation from the wall versus the opening width. Trajectories predicted by the proposed model were then compared with the measurement data which indicated reasonable agreements.     

Modeling thermal behaviors of window flame ejected from a fire compartment

A series of reduced-scale experiments were carried out in order to investigate thermal behaviors of window flame, which exposes the upper floors as well as the adjacent buildings to potential risks of fire spread. A stainless pan filled with alcohol was used as the fire source and was placed inside a cubic compartment of 900 mm side. Temperatures and velocities at various points inside and outside of the compartment were measured. The compartment was pressurized during the experiment by mechanically supplying air at several mass inflow rates through an inlet duct set at the bottom part of the compartment. This was for simulating fire conditions under the effect of external wind pressure. On the basis of the experimental observation, line (i.e., two-dimensional) heat source assumption was adopted for developing a model of window flame behavior. A dimensionless parameter Q^′*${Q^{\prime }}^{*}$ was derived from the governing differential equations in order to generalize the measurement results. Expressions for temperature rise along the trajectory ΔT_m and characteristic flame width b_T were developed incorporating the parameter Q^′*${Q^{\prime }}^{*}$.     

Width effect on upward flame spread

One previous experimental study has reported a width effect for upward flame spread rate on thermally thin fuels. A similar effect is expected for thermally thick fuels. This study revisited this topic by developing a hypothesis and performing experiments with sidewalls using 18 mm thick, 1000 mm tall PMMA slabs of widths 100, 200, 300, 500 and 700 mm. In the hypothesis, a lateral diffusion throughout the flame width was proposed to cause thicker flame along its centerline for wider flames and enhance combustion efficiency. Higher heat release rate per unit width, larger flame height, higher flame temperature and more heat feedback to the surface were consequently present. The corresponding flame spread rate was also increased and a power value of 0.35 existed between the flame spread rate and width in this study. All the experimental results clearly supported the hypothesis.     

增容剂对膨胀型阻燃聚丙烯力学性能的影响

选取聚磷酸铵（APP）/季戊四醇（PER）/三聚氰胺（MEL）组成膨胀阻燃体系,采用马来酸酐接枝聚丙烯（MAH-g-PP）为增容剂,研究了三种膨胀阻燃成分及MAH-g-PP的含量的变化对阻燃聚丙烯力学性能的影响。研究结果表明：随着MAH-g-PP含量的增加,阻燃聚丙烯的力学性能有所改善,在10%以前提高较大,在10%以后增幅趋缓。     

环氧树脂改性水性聚氨酯阻燃涂料的研究

以E-44环氧树脂改性水性聚氨酯为基料,三聚氰胺、季戊四醇为阻燃剂,制备了一种阻燃涂料.测试了该涂料的附着力、耐水性、吸水率、阻燃性及热失重.结果表明,改性后涂料的涂膜附着力达到1级,耐水时间为240 h,吸水率16.5%,阻燃时间可达10 min以上,耐高温及阻燃性能明显提高.     

溴系阻燃剂的应用研究及发展趋势

经过对溴系阻燃剂的市场消费量的分析,表明溴系阻燃剂是一时难以被替代且具有良好发展前景的阻燃剂。阐述了溴系阻燃剂的特点和阻燃机理,重点介绍了阻燃体系中溴系阻燃剂产品及阻燃技术的开发与应用。并针对溴系阻燃剂在使用中存在的二英和毒气等问题,提出了新的研究方向,预测了溴系阻燃剂今后的发展趋势。     

改性聚磷酸铵对三嗪类膨胀阻燃聚丙烯性能的影响

由改性聚磷酸铵(APP)、自制的三嗪类成炭发泡剂(CFA)等复配制成膨胀型阻燃剂(IFR),以二氧化硅、二氧化钛等为协效剂阻燃聚丙烯(PP)。研究了不同组分的IFR及协效剂对阻燃PP复合材料阻燃性能、力学性能和耐水性能的影响。结果表明:改性APP的亲水性下降;由改性APP/CFA(4/1)、二氧化硅协效剂复配的PP复合材料阻燃性能、力学性能优良,助剂在PP基体中分散性好,热水浸泡后氧指数为32.5%,仍能达到UL94V—1级,失重率为2.92%。     

微胶囊红磷膨胀型阻燃剂的制备及应用

制备了微胶囊红磷/季戊四醇/三聚氰胺膨胀型阻燃剂(IFR)。采用吸湿性、抗氧化性、SEM、TG等测试方法对阻燃剂进行了表征。结果表明:微胶囊红磷的吸湿性减小、抗氧化性增强;TG分析显示,微胶囊红磷在385~422℃、470~553℃有两个失重阶段;600℃时,未包覆红磷残重仅为6%,而微胶囊包覆红磷的残重为12%;微胶囊红磷膨胀型阻燃剂的最佳组成为:微胶囊红磷:季戊四醇:三聚氰胺=4.00:0.75:2.00(摩尔比);500℃下,IFR残重高达65.06%;当IFR添加量为30%时,阻燃环氧树脂的氧指数从未添加IFR时的19.0%提高到26.3%。     

我国非炼焦煤在炼焦中的应用

介绍了我国无烟煤、贫煤、不黏煤和长焰煤等非炼焦煤的性质及在炼焦生产中的应用情况。利用非炼焦煤代替部分焦煤炼焦,成本优势十分明显,既可缓解焦煤资源不足的压力,还能优化我国煤炭资源的利用。     

新型高温缓凝剂WHJ在深井固井中的应用

缓凝剂对于保证水泥浆在高温下的流变性是不可缺少的,但目前国内自主开发的高温缓凝剂使用温度均低于180 ℃。为了确保深井高温条件下固井施工的顺利进行,以含磷化合物为主要原料研制出了高分子油井水泥缓凝剂WHJ。该缓凝剂中含有多种易被水泥颗粒吸附、抑制水泥水化能力强的基团,分子与水泥颗粒之间的作用力大,另外缓凝剂分子量大,在高温下的脱附能力差,高温下缓凝性能优良。现场应用结果表明,缓凝剂WHJ在高温下具有良好的抑制水泥水化的能力,具有广阔的推广应用前景。