建筑物走廊型通道中火灾烟气流动特性的研究

应用网络模型方法,将建筑物走廊型通道合理地划分为多个节点,在火源为10kg木材的情况下,利用已开发成功的烟流性状预测软件对四川消防科研所的一座实体建筑物进行了模拟计算,获得了各节点烟流性状的发展变化规律。经比较,模型计算结果与实验数据十分符合。证明走廊型通道的多节点划分方法正确、预测软件实用可靠。根据烟气侵入走道中两节点的时间差及两节点间距,提出了烟气弥漫速度的计算方法。该算法与实测结果间的相对误差小于3%,实例应用及研究的成果,为建筑物火灾时安全疏散动态模拟研究提供了理论依据。     

矿井用箱体防爆面加工安全技术研究

箱体零件是矿井机械中重要的基础零件。它的加工质量直接关系矿井设备的寿命、机器的性能和安全性。针对煤矿井下煤尘和瓦斯存在的环境特性、煤矿井用箱体防爆面加工的特殊要求,采用控制理论的信息流图,对工艺过程中传统方块图进行简化,使繁杂的方块图解采用信息流图表示工艺过程的工序(变量)之间关系。进而讨论箱体零件加工工艺过程误差转换模型、形状精度特征、传递图、描述方程、误差转换结构图;提出防爆面磨削工艺系统的数学模型;求解出振动特性、幅值和相位,得出了形状误差与工艺参数的关系曲线。实践证明,合理选择磨削参数,能够保证煤矿井下工作机械具有高的防爆性能,达到矿井安全生产的技术要求。     

Material flows of end-of-life home appliances in Japan

In Japan, the Law for the Recycling of Specified Kinds of Home Appliances came into effect in April 2001. This law aims to introduce appropriate waste treatment and promote the efficient use of resources so that we can achieve a sound material-cycle society. The law introduces a new framework for recycling that places obligations principally on the manufacturers and retailers of home appliances. Material flow analysis of this new framework is essential for evaluation of the system and for finding any problems that may exist. We therefore analyzed the material flows in facilities that recycle electrical home appliances. The mass balances in the recycling facilities were appropriately estimated. Then the potential destinations were surveyed and analyzed, even though the legal framework does not include flows after the recycling facilities. The potential destination after the facilities varies and depends on both the economy and the related regulations. Currently, considerable amounts of recovered materials are exported and recycled. However, the sustainability of these trades is unknown. Therefore, we should keep a close eye on the situation and make sure that our recycling system is adaptable to meet any future changes.     

单室燃气火灾后果模拟研究

燃气泄漏着火是引发火灾的一个重要原因，其发展过程包括多相湍流流动、燃烧、传热多个分过程。本文将理想单室燃气泄漏火灾的传热传质过程采用CFD（Compulational Fluid Dynamics）方法进行了计算机模拟，对其发展规律及危害性进行了深入研究，得出了火场中的流场、泻度场及有害气体浓度场的分布，为定量研究火灾烟气流动过程以及建立不同危险等级的危险区域提出了依据和研究方法。     

CEMS检测平台流场效应研究与工程设计

本研究项目设计了小型立式环型风洞系统和流场模拟两套实验装置。用工程流体力学实验的方法，对系统内气体压力、流量变化的调节控制方法、通风机的能量消耗，以及在检测平台系统工作段形成均匀流动流场的设计方法等工程实际问题，进行了一系列的试验研究。在试验研究的基础上确定了检测平台系统的设计方案。     

在线浓缩-流动注射分光光度法测定海水中痕量的镉

本文针对海水中镉含量低、海水基体干扰严重等特点，建立了在线浓缩一流动注射分光光度法测定海水中痕量镉的新方法。优化了Cd（Ⅱ）的显色条件、浓缩条件和解吸条件，在最佳检测条件下，Cd（Ⅱ）的检出限为0．02μg/L，线性范围为0．05～2μg/L，相对标准偏差RSD为2.74％（n=g，Ccd（Ⅱ）=1μg／L）。将该方法应用于实际海水中Cd（Ⅱ）的测定。结果满意。     

压入式局部通风工作面风流分布数值模拟研究

笔者应用三维k -ε紊流模型描述压入式局部通风工作面风流的流动过程 ,并采用控制容积法导出了描述流体流动方程的离散化方程式 ;用计算流体力学的方法求得了三维k -ε紊流模型的数值解。采用SIMPLE(压力耦合方程式的半阴解法 )算法解算流场 ;TDMA(三对角线算法 )和Gauss Seidel法结合通过线顺法求解离散方程。利用弱松弛法防止非线性方程组迭代求解过程中的发散现象 ,获得了掘进工作面空间的速度分布 ;并将模拟解算结果与在具有实际尺寸的拱形巷道模型中测得的实验结果进行了对比。数值计算结果与模型实验测定结果非常一致 ,验证了笔者的数学模型和数值模拟方法的正确性。     

Thermal Effects on the Airflow in a Street Canyon – Nantes'99 Experimental Results and Model Simulations

The thermal effects on the airflow within a street canyon, which are produced by the variation of direct solar heating of the street sides and ground, are examined in this article. The investigation is based on the experimental results of the Nantes'99 campaign and numerical simulations performed with the Computational Fluid Dynamics (CFD) code CHENSI using the standard k- model. The Nantes'99 experimental campaign was performed in a North-to-South oriented central street canyon of Nantes, France. It was observed that a thin thermal layer develops locally within a few centimetres from the heated wall. It is anticipated that, the convective flow close to the windward wall, which was visualised during the experiment, carries air masses from the street level upwards, where normally cleaner air is transported. Consequently, thermal effects may be important for the air quality in the street.Based on the temperature and wind flow measurements, the flow and temperature fields were simulated first in two dimensions with the CFD code CHENSI. It was found that CHENSI overestimates the thermal effects on the canyon airflow showing the main re-circulation simulated in the isothermal case to change into two counter-rotating vortices after the inclusion of the heating of the windward wall. A reason for this overestimation is possibly the temperature wall function implemented for such thin thermal boundary layers in conjunction with the limitations in grid resolution.     

泥石流的运动机理和减阻

野外调查研究发现,存在着两种具有不同动力学特征和机理的泥石流,粘滞性泥石流和两相泥石流,粘滞性泥石流由卵石、沙和粘土构成,难以区分固相和液相,为典型的非牛顿体,具有间歇性流动,“铺床现象”,高达60％的减阻和显著超高等流动特点,粘滞性泥石流的阻力远小于流变参数所代表的阻力,传统的利用本构方程研究阻力的方法不能解决问题,研究表明,其30％的减阻是由于铺床作用,另外20％－30％,是由于流动混合物充气所致,两相泥石流主要由粗颗粒物质构成,两相之间有明显的相对流动,显示较大的阻力和发生“石街”现象。粘滞性泥石流沟谷的中值坡度为0．16,两相泥石流阻力大,因而河谷的平均坡度较大（0．19－0．27）。     

一体式膜-生物反应器的水动力学特性

以研究一体式膜 -生物反应器的水动力学特性为目的 ,通过试验测定了反应器中膜间液体错流流速的分布和大小 ,建立了描述错流流速的计算模型 ,并考察了曝气量和反应器结构对错流流速的影响 .曝气量为 40 m³/h时 ,膜组件中部的错流流速为0.36～ 0.4³m/s,比膜组件 2边的流速约大 6.2%～ 21%.错流流速实测值与模型计算值吻合良好 .曝气量为 20～50 m³/h时 ,错流流速随曝气量的升高而增大 ,当曝气量大于 50 m³/h后错流流速逐渐趋向平稳 ;反应器高度越高 ,上升流通道越窄、下降流道和底部流道越宽 ,在同样曝气量条件下 ,可获得越大的错流流速 .