Ventilation simulation for system adjustment of Huangling Coal Mine

Through the usage of simulation software based on the network layout,airway resistances and parameters of main fans,ventilation calculations were performed to ana- lyse the current situation as a ventilation wall built in No.1 west airway to separate the two subsystems.A comparison of simulation results and in-site measurements show that the maximum deviation is less than 10%.Further calculations for the case that the ventilation wall in No.1 west airway is removed to consider the consequences when the two sub- systems are merged together.Results of the simulation show that the total airflow rate in- creases,and the ventilation resistance of the mine decreases in comparing with that of the foregoing simulation.

Coupled heat and moisture transfer in walls featuring moisture-buffering materials and ventilating layers:An Experimental study

The moisture performance of building envelopes largely depends on the building materials,construction tech-niques,and exposure loads from the indoor and outdoor regions.A ventilated air interlayer placed in a wall can help dehumidify the wall and indoor air.This paper presents an experimental study of the heat,air,and moisture variations within the envelope wall of a chamber featuring different air interlayer settings under real outdoor air conditions during the summer of 2020 in Shanghai,China.Self-developed humidity-controlling building mate-rials were applied to the inner building envelope.Temperature,humidity,wind velocity,and heat-flow sensors were placed at different positions in the middle of the wall.These parameters were measured and recorded in real-time under three working conditions:humidification,dehumidification,and ventilation.The experimental results show that under the ventilation working conditions,moisture content of 0.52 kg can be removed after a 2-h air layer ventilation,which can benefit the design strategy for the humidification and ventilation of dehu-midification walls.

综掘工作面风幕阻尘效果影响因素研究

目前综掘工作面粉尘污染的研究多集中于单一因素对综掘工作面风幕阻尘效果的影响,而未充分考虑各因素间的交互作用,使得压风分流技术的工程应用效果欠佳。为明确附壁风筒径向出风距离、径向出风比及轴向出风距离对风幕阻尘效果的影响,以潘三矿810西翼机巷综掘工作面为研究对象,运用Fluent软件对径向出风距离为10~25 m、径向出风比为0.6~0.9及轴向出风距离为6~12 m条件下的风流分布和粉尘扩散情况进行数值模拟。结果表明:(1)随着径向出风距离增大,径向涡流风幕在巷道内的转变更充分,综掘机司机前端的风流分布越均匀,更有利于形成风速方向均指向工作面的轴向阻尘风幕。当径向出风距离为10 m时,距工作面7 m断面内涡流特性明显,风速方向紊乱;当径向出风距离为25 m时,距工作面7 m断面内,风流分布趋于均匀,风速方向均指向工作面,形成了能够覆盖全断面的轴向阻尘风幕。(2)随着径向出风比增大,整流风筒轴向风流风量减小,轴向风流风速和射流强度降低,轴向风流对综掘工作面前端气流的扰动减弱;径向出风比越大,越有利于形成风流方向指向工作面且能覆盖全断面的轴向阻尘流场,即轴向阻尘风幕。(3)径向涡流风幕的阻尘能力随径向出风比的增大先增强后减弱,轴向阻尘风幕的阻尘能力随径向出风比的增大而不断增强。(4)在采取压风分流风幕阻尘技术后,当压风总量为300 m^(3)/min,吸风量为400 m^(3)/min,附壁风筒径向出风距离为20 m,径向出风比为0.9,整流风筒轴向出风距离为8~10 m时,能很好地将粉尘聚集在吸尘口附近,达到高效控尘除尘的目的。在810西翼机巷综掘工作面进行现场测试,测点风速和粉尘质量浓度实测值与模拟值基本一致,高浓度粉尘被有效阻控于工作面前端,隔尘效果较为明显,验证了数值模拟的有效性。

排风口位置对竖壁贴附射流夜间通风降温效果影响的分析

针对成都地区气候特征,开展排风口位置对竖壁贴附射流夜间通风降温效果的分析。选取夏季典型日气象参数进行数值模拟,针对s/b=2,送风速度为4m/s,分析上部排风和下部排风对室内速度场和温度场的影响。上排风和下排风对竖壁贴附区速度场无明显影响,但是下排风情况下水平贴附区射流主体性保持较好,水平空气湖区速度较大。上排风模式下射流沿着壁面继续向上“攀附”一段距离,对贴附墙体降温效果更好。

超高层建筑幕墙全封闭作业环境下的通风降温措施研究

玻璃幕墙封闭环境下的施工作业存在高温、高湿、噪声、大颗粒扬尘、气味等恶劣因素。分析上海浦东某超高层建筑幕墙全封闭情况下对施工环境及作业人员的影响和危害,对比分析目前超高层建筑施工过程中几种常见通风方式现状及其特点,引入结构简单、有通风降温效果、可作为开启窗保护罩的简易通风降温装置,计算夏季高温气候时楼层的所需风量及需要的换气次数。根据项目特点及计算结果制定幕墙全封闭施工作业环境下的通风降温装置研发方案并确定通风降温装置的布置方式,解决了因幕墙封闭给施工现场带来的通风不良、高温等问题。

重症肺炎患儿仰、俯卧位通气联合高频胸壁振荡排痰及超短波理疗的效果比较

目的:探讨仰、俯卧位通气联合高频胸壁振荡排痰及肺部超短波理疗(SW)对重症肺炎患儿氧合指标、痰液特点、血清细胞因子及临床症状改善的影响。方法:选取行机械通气的重症肺炎患儿60例,随机分为仰卧位通气组(SP组)、SP+SW组、俯卧位通气组(PP组)、PP+SW组,各15例。分别观察各组不同时点肺泡-动脉氧分压差、血氧分压、二氧化碳分压、脉搏血氧饱和度、氧合指数、气道内痰液黏稠度和痰液量及血清肿瘤坏死因子α、白细胞介素(IL)-2、IL-6、IL-10水平,以及各组发热时间、啰音消失时间、机械通气时间情况。结果:PP组、PP+SW组各时点动脉血氧分压、脉搏血氧饱和度、氧合指数均明显高于SP组和SP+SW组(P<0.01),肺泡-动脉氧分压差、二氧化碳分压均明显低于SP组和SP+SW组(P<0.01)。机械通气48、72 h,PP+SW组痰液排出量均明显低于其他3组(P<0.01)。PP+SW组24、48、72 h时肿瘤坏死因子α、IL-2、IL-6、IL-10水平均明显低于其他3组(P<0.01)。PP+SW组退热、肺部啰音消失、X线片病灶吸收和机械通气时长均明显低于其他3组(P<0.01)。结论:俯卧位通气下联合高频胸壁振荡排痰及SW能改善重症肺炎患儿氧合指标,降低气道痰液黏稠度并利于排痰,控制机体炎症免疫反应,促进临床症状恢复。

大万山隧道通风斜井中隔墙优化设计方案研究

大万山隧道设有两道通风斜井,长度共计3155m。原设计斜井中隔墙采用钢筋混凝土结构。鉴于钢筋混凝土中隔墙施工进度较慢,延缓整体工期,故文章提出将中隔墙优化为波纹钢板中隔墙的设计方案。该优化方案契合国家推广使用钢结构的理念,可降低施工难度,加快施工进度。经过结构受力验算,采用波纹钢板中隔墙满足受力要求,该方案具有可行性。

均压技术在矿井防灭火中的应用

为了避免毒害气体在煤矿工作面的大面积扩散,防止矿井发生火灾隐患,文章采用均压防灭火技术对单侯矿采区及回采工作面采空区进行了风压调控及防灭火管理。通过均压技术在采区之间风压调节、回采工作面回采结束的封闭及火区控制中的实践应用可知,均压防灭火技术的应用能够有效保障矿工的生命安全,推动煤矿的安全稳定可持续发展。

Experimental Study of the Diffusion of a Confined Wall Jet through a Perforated Plate: Influence of the Porosity and the Geometry

This paper investigated lateral diffusion of a confined two-dimensional wall jet (air inlet height: 5 cm) through a perforated plate. We considered two plates with porosities of and . The plates were positioned at distances of 10 cm and 20 cm below the jet inlet. The experiments were realized using 2D Laser Doppler Anemometer (LDA). Different profiles of mean and fluctuating velocities are presented. The presence of a perforated plate strongly modified the airflow pattern compared to an empty enclosure. The velocities above and below the plate depend on several parameters, including the porosity and the plate’s position relative to the inlet slot and the longitudinal position. The difference between the flow velocity above and below the plates could not be related using a universal formula that depends on these parameters. We also investigated the influence of a porous media of a height of 20 cm (a stack of spheres having a diameter of 3.75 cm) located below the perforated plate. The results highlight that the porous medium strengthens the effects of the perforated plate on the flow.

Experimental and Numerical Investigation of the Diffusion of a Confined Wall Jet through a Perforated Plate

When performing numerical modeling of fluid flows where a clear medium is adjacent to a porous medium, a degree of difficulty related to the condition at the interface between the two media, where slip velocity exists, is encountered. A similar situation can be found when a jet flow interacts with a perforated plate. The numerical modeling of a perforated plate by meshing in detail each hole is most often impossible in a practical case (many holes with different shapes). Therefore, perforated plates are often modeled as porous zones with a simplified hypothesis based on pressure losses related to the normal flow through the plate. Nevertheless, previous investigations of flow over permeable walls highlight the impossibility of deducing a universal analytical law governing the slip velocity coefficient since the latter depends on many parameters such as the Reynolds number, porosity, interface structure, design of perforations, and flow direction. This makes the modeling of such a configuration difficult. The present study proposes an original numerical interface law for a perforated plate. It is used to model the turbulent jet flow interacting with a perforated plate considered as a fictitious porous medium without a detailed description of the perforations. It considers the normal and tangential effects of the flow over the plate. Validation of the model is realized through comparison with experimental data.

合肥地区窗墙比对动态自然通风能耗的影响研究

以合肥地区某实际办公建筑为例,采用计算流体力学与建筑环境及暖通系统模拟技术,采用自然通风与建筑室内热动态耦合模拟分析,基于不同自然通风形式,利用多区域通风网络原理,得到了自然通风量逐时动态变化的耦合基准模型,研究在动态自然通风情景下窗墙比对建筑能耗的影响。研究结果表明,在合肥地区实际动态自然通风情景下,随窗墙比的增加,混合自然通风形式的全年节能率在16.65%~17.17%之间,贯流自然通风形式的全年节能率在16.56%~17.41%之间,单侧自然通风全年节能率则在15.39%~18.65%之间,可为合肥地区基于实际自然通风量逐时变化情景下建筑节能设计工作提供参考。

基于均流板原理的通风墙型植物工厂循环送风系统设计与模拟

植物工厂是当前可控农业环境的最高形式之一,但植物工厂内温度、气流空间分布不均,不同栽培架之间存在一定温差、气流速度差。为解决气流植物工厂内局部环境因子差异大的问题,该研究对植物工厂进风口设置进行改进,在侧进上出气流循环模式下,借鉴均流板原理设计了一款全网孔通风墙型植物工厂,并通过计算流体力学软件(computational fluid dynamics,CFD)进行模拟,分析该类型工厂下温度、气流速度、CO_(2)浓度、相对湿度、适宜风速占比、空气龄、指定流线速度变化情况,以评价全网孔通风墙对植物工厂内局部环境差异的改进效果。该设计平均空气龄为7.5 s,是无全网孔通风墙条件下的1/9,空气更新效率有效提升。研究表明全网孔通风墙型植物工厂能有效提升植物工厂内环境因子分布均匀性。

壁面受热位置对非均匀街谷内流动的影响研究

为探讨弱风条件下,街谷壁面受热位置给不对称街区的内部流动及扩散造成的影响,对具有不稳定热分层效应的非均匀街谷进行了数值模拟研究。探讨了3种街谷壁面受热位置对非均匀城市街区通风换气特性与远场气态污染物扩散规律的影响。结果表明,壁面受热位置的改变会显著影响街谷内的气流形态与污染物分布;街谷壁面的热效应可以促进街谷内部的通风换气能力;在非均匀街谷内,远场污染物扩散路径的影响要大于气流特性的影响,上阶梯型街谷的大气弥散因子显然高于下阶梯型街谷。

易燃易爆试剂室安全性工艺设计探索

易燃易爆试剂室存有重大安全隐患,是消防安全管理的要害部位,是各行业检验检测实验室的必备功能间。依据国家标准,易燃易爆试剂室不能放进民用建筑,大多数实验室工程项目没有建设在工业用地,也没有条件在实验楼外单独建设试剂室。设计与建设单位为通过审图和消防验收,设计图样回避“试剂室”字样,竣工消防验收后,在装饰装修阶段把试剂室放进实验楼,违反建筑规范,给实验楼带来安全隐患。针对上述问题,提出了较为安全的新型试剂室与民用建筑的结合方法。创新点如下:1)在不违反标准规范的情况下,让易燃易爆试剂室能够“间接放进”按民用建筑设计的实验室;2)试剂室建于实验楼北侧一角能形成自然对流通风的位置;3)试剂室具有自然通风、防雨、泄爆、遮光的特征,通风泄爆轻质外墙采用竖直曲面百叶集成;4)试剂室的安全内装。

冬季太阳能相变蓄热通风墙热工性能的数值模拟

在建筑通风墙体中加入相变材料被认为是改善其冬季热工性能的有效方法。相变材料在墙体中可采用分块的方法进行宏观封装,此时材料在熔化过程中产生的自然对流现象十分显著,不能被忽略。该文使用开源计算流体力学框架OpenFOAM下开发的求解器针对被动式相变蓄热通风墙体的热工性能开展了数值研究,以准确模拟相关传热、流动、相变等物理过程。计算结果表明:相变材料蓄热墙能有效降低室内温度波动;相变材料内部的自然对流作用很大程度上影响着材料的熔化与凝固速度,因此材料封装时的长宽比以及分块方式应做出审慎选择。

附壁风筒出风口参数对掘进工作面控尘效果的影响

为明确径向出风式附壁风筒出风口宽度、径轴向出风比对综掘工作面控尘效果的影响,以冯家塔煤矿某综掘工作面为原型,运用FLUENT软件,对建立的长压短抽式通风综掘巷道模型进行数值模拟,并对模拟结果进行现场验证。结果表明:保持压抽比为1.3,径向出风口长为0.8 m时,随着出风口宽度增加,巷道空间内的粉尘浓度先减小随后增大,改变出风口宽度,当出风口宽度为0.05 m时,司机处粉尘浓度降至100 mg/m^(3),距掘进工作面20 m巷道内基本无粉尘,控尘效果最佳;保持最佳出风口宽度为0.05 m,随着径轴向出风比变小,巷道内粉尘浓度先减小后增大,当径向轴向出风比为1:2时,粉尘被集中控制在负压抽吸区,掘锚机司机位置处粉尘浓度降至1.2 mg/m^(3),此时径向出风式附壁风筒控尘效果最佳。

基于能耗计量的建筑节能降耗策略优化研究

能耗计量是科学评价建筑能源应用的方式,从行业能源应用的角度展开分析,有必要降低建筑全生命周期的能耗。从建筑能耗计量的角度提出节能降耗的应用策略,通过外墙保温技术、建筑暖通空调应用,从项目管理和应用技术等方面提出践行建筑节能的有效方式。高品质的外墙保温工程和新型暖通空调设备均能够实现建筑节能效果,从能耗计量的角度分析,两种措施均能够有效降低建筑能耗。在建筑节能探索的过程中,应进一步完善能源管理体系、应用先进技术形式,有助于建筑节能目标的达成。

Study on attached ventilation based on inclined walls

In practical engineering,inclined building walls are often presented due to their functional and aesthetic needs.A reasonable air distribution design is essential for creating a satisfactory indoor environment in such buildings.In the present study,inclined walls with a variable inclination angle β were used as the research object to explore a novel air supply mode.Visualization experiments and numerical simulations were conducted to investigate the induced airflow,such as the airflow pattern,the airflow characteristics(maximum jet velocity decay and jet spreading rate)and the ventilation effect(vertical air temperature difference,draft rate,air diffusion performance index).The results show that the"air lake"phenomena occurred over the floor,which resembles the displacement ventilation to some extent.The proposed air supply mode has a good ventilation effect and could be applied to building spaces with inclined walls.The current study can be used as a reference for ventilation design in buildings with inclined walls.

LNG动力船双壁管通风设计及风机选型

LNG动力船的应用已经进入快速发展阶段,但作为气体燃料,LNG仍存在较大的安全风险。因此,在设计时需额外考虑更多的安全措施,来保证燃气系统的安全性。大型船舶中燃料准备间到机舱距离较远,比中小型船舶的泄露风险更高,燃气供应除了由供气管路主阀控制,还需要GECU协同控制。以16000TEU LNG双燃料集装箱船为例,介绍了LNG动力船双壁管通风设计的方法,完成了GVU及GECU通风管路的双壁管通风量计算、进风口流量分配及管路压强损失等完整计算,为之后风机初步选型工作提供了参考。

以礼河四级水电站复建工程通风空调系统设计

以礼河四级水电站复建工程的地下厂房采用以机械通风为主、空调和除湿为辅的通风空调方案,利用进厂交通洞和厂区进风洞作为进风道,利用厂区排风洞和出线竖井作为排风道,地下厂房形成“二进二排”的气流组织。地下厂房通风系统充分利用岩壁夹墙内空间安装通风管道,采用夹墙风管方案,节省厂房内的安装空间。通风空调系统经济合理、稳定可靠。