共查询到19条相似文献,搜索用时 203 毫秒
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特长隧道通风系统选型的探讨 总被引:2,自引:0,他引:2
介绍国内外特长隧道通风系统设置现状,分析了影响通风系统形式的相关因素,并以目前国内某一特长水域公路隧道的通风设计方案比选进行分析。 相似文献
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基于FLUENT软件对自然风与交通风在公路隧道内运动特性进行数值模拟,考虑车辆行驶速度,交通量、自然风风速与风向对隧道通风影响.计算结果表明,交通风风速随着车辆行驶速度和交通量的增加而增大,两者之间存在一定的函数关系.自然风风向与行车方向相同时,隧道内风速随自然风风速增大而增大,两者相反时自然风明显抑制隧道通风. 相似文献
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蔡珊瑜 《地下空间与工程学报》2004,24(1):75-79
介绍国内外特长隧道通风系统设置现状 ,分析了影响通风系统形式的相关因素 ,并以目前国内某一特长水域公路隧道的通风设计方案比选进行分析。 相似文献
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针对高楼山隧道特殊的工程特点,本文展开通风方案研究。首先,借助规范及以往工程设计经验计算高楼山隧道的需风量,通过计算分析得出,全射流纵向通风不能满足高楼山隧道运营通风的需要,宜采用分段式通风。其次,通过对各分段式通风方案进行定量分析比选得出,高楼山隧道钻爆法施工采用2斜井送排式与射流风机组合通风方案,TBM导洞扩挖方案采用1斜+1竖井通风方案。 相似文献
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以青山界隧道为背景,对青山界隧道的通风方式进行了简要介绍,并对其进行了分析,根据相应规范确定了风机、风管的安装形式,最终通过通风量的计算,确定其通风方案、通风机型号,解决了本隧道的通风问题。 相似文献
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本文对隧道自然通风的传统模拟方法进行了修正,认为不断变化的加速度能够储存部分能量,交通风压及阻力做功并非全部转化为空气的动能。通过算例分析以及模型实验验证,证明修正的正确性及必要性。为设计人员进行隧道通风设计时提供更为准确的计算方法。 相似文献
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Wind tunnel investigation on influence of fluctuating wind direction on cross natural ventilation 总被引:1,自引:0,他引:1
The performance of wind driven natural ventilation is influenced significantly by the boundary conditions set for the wind. In real conditions the wind direction is fluctuating constantly so it is important to consider this fluctuation in experiments and simulations. This paper investigates the influence of fluctuating wind direction on cross-ventilation using wind tunnel experiments with the aim of improving the evaluation accuracy for natural ventilation. A periodically fluctuating wind direction was designed and reproduced in the experiment. Rapid Response FIDs (Flame Ionization Detector) were used to monitor the concentration of tracer gas. An index named diluting flow rate (DFR) is introduced to evaluate the ventilation performance of this kind of experiment. The results indicate that the DFRs of fluctuating cases are approximately 65–100% of the maximum airflow rate and DFR is influenced by the wind speed, the opening size and the wind direction fluctuation. Informed by the experimental data the mechanism of this combined influence is discussed in this paper. 相似文献
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针对公路隧道通风计算中存在的问题,对车辆有害物的基本排放量、修正系数、阻滞模式、允许浓度等做了较为详细的论述。介绍了公路隧道通风量的计算方法,以保证隧道的交通功能。 相似文献
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本文对隧道施工掘进中的通风方式、风量及设备选型等问题进行了较为系统的论述,提供了隧道施工通风的计算方法,在隧道施工中具有借鉴作用。 相似文献
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为研究不同百叶窗透风率下超大型冷却塔内吸力风振系数的分布特性和取值,以国内某在建210m高超大型冷却塔为工程背景,首先通过同步刚体测压风洞试验,得到了不同透风率(0%、15%、30%及100%)下冷却塔结构内表面平均与脉动风荷载。在此基础上,对比分析不同透风率平均和脉动风压分布特性,并采用有限元方法建立了塔筒-支柱-环基一体化仿真分析模型,对该超大型冷却塔进行四种内吸力作用工况下完全瞬态时域动力计算。对比了四种透风率下内吸力风振系数的一维、二维和三维分布特征,分析了以塔筒径向位移、子午向轴力、von Mises应力和环向弯矩四种典型目标响应下的风振系数取值标准,分别给出了此类超大型冷却塔不同透风率下内吸力风振系数的取值建议,即0%、15%、30%及100%透风率下内吸力风振系数分别取为1.69、1.79、1.69和1.57。 相似文献
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Even though opening a window for ventilation of a room seems very simple, the flow that occurs in this situation is rather complicated. The amount of air going through the window opening will depend on the wind speed near the building, the temperatures inside and outside the room, the wind direction, the turbulence characteristics in the wind and the pressure variations caused by e.g. wind gusts. Finally, it also depends on the size, type and location of the opening. Many of these parameters are unsteady which makes the calculation of air-change rates even more complicated. In this work, full-scale wind tunnel experiments have been made with the aim of making a new expression for calculation of the airflow rate in single-sided natural ventilation. During the wind tunnel experiments it was found that the dominating driving force differs between wind speed and temperature difference depending on the ratio between the forces and the wind direction. This change is also found in the velocity profiles measured in the opening, which might change from wind dominated to temperature dominated under the same wind direction but with increasing temperature difference. 相似文献