重庆市嘉华隧道通风系统设计

结合工程实际情况,对目前重庆主城区最大隧道嘉华隧道的通风方式选择、需风量计算、风机组合设计等具体过程以及火灾时的通风控制进行了介绍,以满足车辆正常行驶条件下的隧道需风量。     

公路隧道平行导洞结合分段纵向通风系统研究

针对高海拔隧道和水下隧道因建设条件、地理条件和环评要求等因素影响不便修建竖、斜井的问题,提出了平行导洞—分段纵向通风系统。在隧道通风理论的基础上,推导了适用于该通风系统的设计参量的计算公式;同时结合隧道通风设计程序,给出了从隧道分段位置确定、设计风量计算、设计参数初始值计算到污染物浓度校核的设计流程,从隧道长度限制和需风量,初步分析了混合通风方式的适用条件。结合工程案例,给出了混合通风方式的实际应用方案,方案在不修建竖井的前提下,结合集中排烟通道很好地解决了火灾人员逃生问题,具备实际可行性,为今后穿越高海拔和跨海公路隧道的通风设计提供了新思路。     

长大隧道独头压入式通风技术

结合某隧道工程实例,介绍了长大隧道独头压入式通风技术,设计参考了国内其他隧道通风的实际情况,通过计算隧道施工通风的理论通风量,并根据现场实际情况,提出变更加大斜井断面尺寸和采用柔性风管,配用两台隧道施工专用通风机,可以随隧道掘进长度的增加逐步加大通风量,以达到节能目的。     

红石岩隧道施工通风技术研究

介绍了红石岩隧道针对瓦斯的施工通风解决方案,主要从施工通风方式的选择、风量风压计算和通风设备的选择等方面对施工通风进行了研究,并提出相应建议,为类似的工程问题提供了经验和指导。     

地铁区间隧道火灾通风模式的数值模拟

针对列车中部着火且停靠在区间隧道中部的地铁隧道火灾情况,提出了一种改进的纵向通风模式,即疏散平台下先送风、再采用传统的纵向通风,并进行了数值模拟.模拟结果表明,时单线矩形区间隧道,在10 MW的火源强度下,当疏散平台下送风风口组间距为10m且隧道风机风量为50 m3/s时(或风口组间距不超过30 m且隧道风机风量为70m3/s时),可以满足安全消防的温度指标、能见度指标和CO浓度指标.同时模拟得出区间隧道两端纵向通风的临界风速在2.4～2.8 m/s之间.     

大直径长距离盾构隧道施工通风方案探讨

文章以福州滨海快线富水砂层盾构法施工为工程背景,对长达4 000 m隧道独头掘进和内部结构同时施工的隧道通风进行了研究。首先,通过相关规范和施工经验选择压入接力式通风方式;然后针对工程特点对隧道所需通风量进行了理论计算,充分考虑了地质有害气体、人员需风量、漏风率的因数;最后通过所需通风量计算风压,确定风机的技术参数,实现了富水砂层长距离大直径独头掘进4 000 m的压入式通风,为类似项目隧道施工通风提供了可靠的借鉴。     

公路隧道稀释NO_2需风量确定的必要性分析

本文通过分析公路隧道通风系统设计风量的确定方法,探讨公路隧道控制NO_2浓度需风量确定的必要性。结合工程案例,对公路隧道通风系统设计风量与控制NO_2浓度需风量进行了对比。结果表明:隧道通风系统设计风量并未明显大于控制NO_2浓度需风量,在进行公路隧道通风系统设计时宜进行NO_2需风量验算。     

特长隧道通风方式的分析

文章以博深高速公路石鼓特长隧道为实际案例,从隧道内一氧化碳、烟雾允许浓度、汽车尾气排放量等因素分析隧道需风量,依据需风量对隧道各通风方案进行比选,进而选择最优的通风方案。     

风口参数对集热蓄热墙通风及换热特性的模拟研究

为了提高集热蓄热墙的通风与换热特性,分别设计了有外保温结构的集热蓄热墙通风和供热的模型,使用Fluent模拟软件对有外保温结构的集热蓄热墙的不同风口参数下的集热蓄热墙通风和供热性能进行模拟。得知风口形状、风口面积及进出风口的相对大小都对有外保温结构的集热蓄热墙通风和供热特性产生了较大影响,其中长方形风口优于正方形风口;风口面积等比增大可提高其通风量减少其换热量;对于夏季通风模式,风口的出口面积大于进口面积可增大通风量;对于冬季供热模式,出口面积小于进口面积可增大换热量。在实际工程中应合理设计风口,以达到集热蓄热墙的最佳性能。     

盾构施工通风的初步探讨

以某工程为例,对长距离隧道通风所需的风压、风量进行了计算,对出现的通风不足的问题提出了解决方法,并对盾构施工的通风方式提出建议,指出隧道通风对保障作业人员的健康以及盾构机的正常运行,有着重要的作用。     

冬季北方地区住宅建筑通风方式对比研究

随着住宅节能技术的广泛推行,对窗户的气密性要求越来越高,冬季冷风渗透远远不能满足室内人员对新风的最低需求。为了寻找节能、舒适的通风方式,本研究利用FLUENT对工程中较为常见的通风方式：自然通风方式、自然进机械排通风方式、带热交换的墙式通风器方式、带热交换的通风换气机组方式在气流组织、舒适性能、能耗特性及初投资方面进行了应用效果评价。最终得出：对于层高和装修标准较高的高级住宅中使用带热交换的通风换气机组,可以使通风系统在满足热舒适性和空气品质的基础上,更加节能,而对于一般住宅建筑,自然进机械排通风方式是相对最优选择。     

地铁隧道活塞风井通风性能的数值模拟研究

本文采用CFD方法对某设有站台屏蔽门和活塞风井的地铁站中的自然通风系统进行了研究。文中建立了全尺寸几何模型,采用动网格方法模拟列车运行时引起的流域边界变化,通过求解三维非稳态雷诺时均N-S方程来获得地铁隧道、站台区域以及通风竖井中的流动特点。本文定义了2个参数,有效排风量Ne和有效进风量Ns,用来评价活塞风井的通风效率,主要分析了实际列车运营状况下,地铁站不同的风井数量、风井位置对活塞风井通风性能的影响。研究结果对于拟建地铁站的风井结构设计具有参考意义。     

合肥地区公共建筑夏季通风分析

本文首先根据合肥地区典型气象年(设计典型)夏季气象参数,得出该地区夏季通风的基本原则:白天在满足卫生要求的前提下,限制通风为主;夜间加强通风,在室外温度空气温度升高时停止通风。然后以该地区某办公建筑为研究对象,分析了不同等级热惰性围护结构下最佳通风策略,得出Ⅰ型结构在白天通风策略一定时,夜间通风为9次/h左右较为经济,Ⅱ、Ⅲ、Ⅳ型结构夜间通风为5次/h左右较为经济,并指出该地区较适合夜间通风的围护结构的热惰性类型。     

On the transition from displacement to mixing ventilation with a localized heat source

We investigate the steady state natural ventilation of a room heated at the base and consisting of two vents at different levels. We explore how the air flow rate and internal temperature relative to the exterior vary as a function of the vent areas, position of the vents and heat load in order to establish appropriate ventilation strategies for a room. When the room is heated by a distributed source, the room becomes well mixed and the steady state ventilation rate depends on the heating rate, the area of the vents and the distance between the lower and upper level vents. However, when the room is heated by a localised source the room becomes stratified. If the effective ventilation area is sufficiently large, then the interface separating the two layers lies above the inlet vent and the lower layer is comprised of ambient fluid. In this case the upper layer is warmer than in the well mixed case and the ventilation rate is smaller. However, if the effective area for ventilation is sufficiently small, then the interface separating the two layers lies below the inlet vent and the lower layer is comprised of warm fluid which originates as the cold incoming fluid mixes during descent from the vent through the upper layer. In this case both the ventilation rate and the upper layer temperature are the same as in the case of a distributed heat load. As the vertical separation between lower and upper level vents decreases, then the temperature difference between the layers falls to zero and the room becomes approximately well mixed. These findings suggest how the appropriate ventilation strategy for a room can be varied depending on the exterior temperature, with mixing ventilation more suitable for winter conditions and displacement ventilation for warmer external temperatures.     

Effects of vent shaft location on the ventilation performance in a subway tunnel

A computational analysis of a ventilation system in a subway tunnel is carried out by solving 3D Reynolds-averaged Navier–Stokes equations for train-induced unsteady flow using the sharp interface method as the model for the moving boundary of an immersed solid. The ventilation performance is evaluated depending on the location of the vent shaft by analyzing the ventilating flow rate through the shaft and the feature of the flow field in the subway tunnel around the shaft. It is found that the optimum location of the vent shaft with respect to maximizing ventilation performance lies near the station.     

综合管廊电缆舱室通风形式数值模拟研究

通过数值模拟的方法,对青岛某综合管廊电缆舱室通风系统进行研究。采用传统的机械排风加自然补风通风系统,舱室平均温度为31.8℃,但排风口平均温度达到43.6℃,高于设计标准的限值40℃。采用诱导通风系统,舱室内平均温度为31.5℃,排风口平均温度降至37.3℃,保障了舱室顶部设备的正常运行。对两种通风方式下电缆舱内温度场均匀性进行分析,研究发现:舱室内温度场方差分别为6.645和4.667,诱导通风系统空气温度分布均匀性优于机械排风加自然补风通风系统。此外,对两种通风方式下电缆舱内速度场进行分析对比,结果表明:沿舱室高度方向,诱导通风系统的平均风速大于机械排风加自然补风通风系统,空气流动死角较少,更有利于舱室内的气流组织。     

Heat source modelling and natural ventilation efficiency

We compare natural ventilation flows established by a range of heat source distributions at floor level. Both evenly distributed and highly localised line and point source distributions are considered. We demonstrate that modelling the ventilation flow driven by a uniformly distributed heat source is equivalent to the flow driven by a large number of localised sources. A model is developed for the transient flow development in a room with a uniform heat distribution and is compared with existing models for localised buoyancy inputs. For large vent areas the flow driven by localised heat sources reaches a steady state more rapidly than the uniformly distributed case. For small vent areas there is little difference in the transient development times. Our transient model is then extended to consider the time taken to flush a neutrally buoyant pollutant from a naturally ventilated room. Again comparisons are drawn between uniform and localised (point and line) heat source geometries. It is demonstrated that for large vent areas a uniform heat distribution provides the fastest flushing. However, for smaller vent areas, localised heat sources produce the fastest flushing. These results are used to suggest a definition for the term ‘natural ventilation efficiency’, and a model is developed to estimate this efficiency as a function of the room and heat source geometries.     

Natural ventilation of indoor spaces while minimizing heat losses: Theoretical and experimental investigation

Limiting heat losses during ventilation of indoor building spaces has become a basic aim for architects, particularly since the oil crisis of 1970. Much experience has been gained in terms of ventilation of indoor spaces. Nevertheless, due to the complex applications, attempts to create a theoretical base for solving the problems related to the issue are limited, especially determining the minimum ventilation period required within a designated space. In this paper we have approached this matter, both theoretically and experimentally. The conclusion we reached was that controlled ventilation of spaces through vent holes that successively open and close at regular time intervals can limit the excessive circulation of air masses, which in turn limits heat losses.     

舞台自然排烟口风量计算

本文着重介绍了舞台自然排烟排烟口面积的计算及排烟口风量计算。     

置换通风气流组织及其影响因素分析研究

利用数值模拟置换通风的气流组织的速度场，温度场，分析了热源的大小以及所处的位置，送回风口相对位置等因素对气流组织的不同影响，为评价这种通风方式的舒适性提供参考依据。