基于湿式除尘的扬尘抑制技术研究进展

扬尘作为一种常见的无组织排放源,是大气污染物的重要组成部分.随着环境质量要求的提高,扬尘的高效去除问题受到重视.研究揭示湿式抑尘的作用机理,分析影响抑尘效率的条件因素,对不同湿式方法抑制扬尘的工艺特点及应用情况进行评价.结果表明,湿式抑尘技术主要作用机理为碰撞、拦截、重力沉降、布朗扩散,细水雾与粉尘间存在核化凝结过程与...     

抑尘车科学化管理调度的设想

针对抑尘车管理调度中存在的问题，提出了利用GPS定位监管调度系统，严格监管抑尘车、驾驶员和对突发事件、应急任务及时响应的设想．     

抑尘、防尘措施在甘肃某火电厂的研究应用

系统分析火电厂粉尘的来源类型和产生环节,介绍甘肃某火电厂的抑尘、防尘措施.     

挡风抑尘墙在散堆料场的应用

介绍挡风抑尘墙的原理及设置应考虑的各种因素.     

铁路煤炭运输抑尘剂喷洒系统的设计思路

叙述了铁路煤炭运输抑尘的方法及摆臂式防尘喷洒智能控制系统设备,分析了该设备的效益。     

火电厂喷雾抑尘系统设计研究

结合实际工程对带式输送机喷雾抑尘系统进行探讨,提出不足与解决方案,可以对今后类似工程的燃料输送系统设计提供借鉴。     

微米级干雾抑尘在桥式卸船机及圆形煤场的运用

传统抑尘技术已无法满足大型燃煤火电厂输煤系统的需求,而微米级干雾抑尘技术较完善地解决了重点抑尘部位的粉尘治理问题。简要介绍了燃煤火电厂起尘点以及现有的抑尘技术,并通过某厂微米级干雾抑尘技术在大型煤码头及圆形储煤场中的运用,证明了该技术基本满足了大型燃煤火电厂输煤系统粉尘治理需要,有效地减少了粉尘对人体和环境的危害。     

阜新市主要城市绿化树种滞尘能力评价

对阜新市10种主要绿化树种的滞尘能力进行了测定.结果表明,不同树种的滞尘量差异显著,树种间滞尘能力的差值可达2倍以上.落叶乔木中,臭椿、枫树的滞尘能力较强.紫丁香,榆叶梅为滞尘能力较强的落叶灌木.同种树种在不同功能区的滞尘能力也存在较大的差异,这是由于叶片滞尘受外界环境干扰较大造成的.在上述研究的基础上提出以植物的滞尘功能作为城市绿化设计的重要依据.     

低排尘浓度流动燃烧锅炉的实验研究

详细叙述了一种低排尘浓度流动燃烧锅炉的工业实验研究结果。采用这种燃烧方式,在不装设除尘器条件下,燃用一般原煤时,排尘浓度可明显低于我国1类地区的烟尘排放浓度限值——200mg/m~3。     

碎煤机无动力控风抑尘系统研究

针对PM2.5颗粒在生活和生产中的危害,讨论燃煤电厂存储运输过程中抑尘方法,对传统除尘设备进行改进,结合目前行业比较先进的无动力控风抑尘系统进行全面解析,探索输煤抑尘的新途径。     

塔山白洞井综合防尘技术应用研究

对采用的煤体注水、采煤机内外喷雾、负压二次降尘综合防尘技术进行了分析,并探讨了其应用情况及经济效益。采用煤层注水后,工作面产生粉尘的质量浓度明显降低。在采煤机摇臂上增设外喷雾装置,割煤时打开,可有效提高采煤机喷雾降尘效果。采煤机负压二次降尘装置能在不同角度喷雾形成水雾,且喷雾形成的负压将摇臂和滚筒底部的粉尘吸入降尘器湿润后落下,对抑制粉尘起到关键性作用,相比粉尘质量浓度下降了40%。     

Suppression of hydrogen/oxygen/nitrogen explosions by fine water mist containing sodium hydroxide additive

Complementary sets of experiments, consisting of burning velocity measurements and vented explosion tests, have been undertaken for a wide range of hydrogen–oxygen–air test compositions using fine water mist with NaOH additive (SMD ∼ 4 μm). In contrast to pure water mists, burning velocity measurements identified a critical mist concentration (for a given gas composition) above which a sudden large decrease in burning velocity is observed. The critical concentration was also found to correspond to an inerting concentration during vented explosion testing. Prior to reaching the critical concentration, the NaOH additive had a negligible effect on both the burning velocity measurements and explosion tests. This clearly indicates that the NaOH additive is acting as a chemical inhibitor. The inhibiting effect is generally considered to occur due to homogeneous gas phase mechanisms and it is thought likely that only the fraction of the entire mist (with droplet diameter < 2.5 μm) would evaporate sufficiently quickly to allow vaporised NaOH to take part in the inhibition. The experimental data obtained have enabled the construction of an inerting map to facilitate the design of a practical mist inerting system.     

细水雾对油池火热释放速率影响的初步研究

热释放速率是反映火场规模与发展的最重要的基础参数，利用ISO9705实验台进行细水雾灭火有效性的影响因素及相关机理研究，不仅能营造出一个真实的室内火灾环境，而且能够得到火场的热释放速率。对汽油池火的初步实验表明：热释放速率曲线能直接反映出细水雾对火源的作用；细水雾作用下燃烧总的热释放量减少很大；开启水雾的时间不同，细水雾对热释放速率峰值的削减程度不同。     

Numerical model validation and prediction of mist/steam cooling in a 180-degree bend tube

To achieve higher efficiency target of the advanced turbine systems, the closed-loop steam cooling scheme is employed to cool the airfoil. It is proven from the experimental results at laboratory working conditions that injecting mist into steam can significantly augment the heat transfer in the turbine blades with several fundamental studies. The mist cooling technique has to be tested at gas turbine working conditions before implementation. Realizing the fact that conducting experiment at gas turbine working condition would be expensive and time consuming, the computational simulation is performed to get a preliminary evaluation on the potential success of mist cooling at gas turbine working conditions. The present investigation aims at validating a CFD model against experimental results in a 180-degree tube bend and applying the model to predict the mist/steam cooling performance at gas turbine working conditions. The results show that the CFD model can predict the wall temperature within 8% of experimental steam-only flow and 16% of mist/steam flow condition. Five turbulence models have been employed and their results are compared. Inclusion of radiation into CFD model causes noticeable increase in accuracy of prediction. The reflect Discrete Phase Model (DPM) wall boundary condition predicts better than the wall-film boundary condition. The CFD simulation identifies that mist impingement over outer wall is the cause for maximum mist cooling enhancement at 45° of bend portion. The computed results also reveal the phenomenon of mist secondary flow interaction at bend portion, adding the mist cooling enhancement at the inner wall. The validated CFD simulation predicts that average of 100% mist cooling enhancement can be achieved by injecting 5% mist at elevated GT working condition.     

Numerical Simulation on Turbine Blade Leading-Edge High-Efficiency Film Cooling by the Application of Water Mist

Numerical simulation is performed to explore leading film cooling enhancement by the application of injecting water mist into the air. The accuracy of numerical simulation program for conjugate heat transfer methodology is verified with the C3X gas turbine vanes cooled with leading edge films. The effect of various parameters including mist concentration, mist diameter, different particle wall interactions conditions, and different forces on the improvement of cooling performance is investigated in this paper. It indicates that mist film cooling can decrease the temperature of boundary layer without impact on the temperature of the mainstream and the thickness of boundary layer.     

细水雾灭油池火过程中火焰强化现象的实验研究

细水雾灭火初期,在短时间内会观察到剧烈燃烧的火焰强化现象。设计了多组实验对比不同燃料在不同工况下的火焰强化现象,发现液滴通过撞击油盘燃料引起的液滴飞溅可以增大燃料与空气的接触面积,强化火焰燃烧。细水雾在燃料内发生扬沸也可能强化火焰,但增益效果不明显,同时燃料气化率对于火焰强化程度有很大关系。     

Modelling of improved energy performance of air-cooled chillers with mist pre-cooling

Air-cooled chillers are widely used to provide cooling energy and yet pragmatic and simple energy efficient measures for them are still lacking. This paper considers how their coefficient of performance (COP) can be improved by using mist to pre-cool ambient air entering the condensers. The benefit of this application rests on the decrease of compressor power resulting from the reduced condenser air temperature with insignificant consumption of water and pump power associated with the mist generation. Based on a simulation analysis of an air-cooled screw chiller operating under head pressure control, applying such mist pre-cooling enables the COP to increase by up to 7.7%. Precise control of mist generation rate and integration with floating condensing temperature control are the major challenges of using a mist system to maximize electricity savings. The results of this study will prompt low-energy operation of existing air-cooled chillers working for various climatic conditions.     

细水雾作用下气体射流火焰熄灭的临界条件

设计了开放空间条件下细水雾扑灭气体射流火的模拟实验,发现可燃气体流率大小和火焰上升力大小都直接影响了灭火成功与否,进而通过理论分析和计算分别得出了细水雾灭射流火的临界条件,细水雾的吸热功率大于11%～15%射流火的火源功率时可实现灭火,射流上升力与细水雾下压力的比值小于1.0～2.8时细水雾也能够通过克服火焰上升力进而实现灭火,实验结果也显示,相同气体流率情况下气体射流上升力与细水雾下压力的比值越大则灭火时间越长.     

A numerical simulation of the suppression of hydrogen jet fires on hydrogen fuel cell ships using a fine water mist

In this paper, in order to evaluate the reliability of a fine water mist for the suppression of fires on hydrogen fuel cell ships, the fire dynamics simulator (FDS) software was used to simulate the jet fire process and the action of a fine water mist on a fire caused by a hydrogen leakage in the hydrogen storage tank areas of hydrogen fuel cell ships. The fire scenario was classified into vertical or horizontal jet fires according to the location of the leakage in the hydrogen storage tank area, and the suppression effects of a fine water mist on hydrogen jet fires under a different droplet size, spray velocity, and ambient wind speed were compared and analyzed. The results indicate that a fine water mist is not effective in extinguishing hydrogen jet fires; however, by selecting suitable parameters (a spray velocity of 30 m/s and average droplet size of 30 μm), it can effectively reduce the fire field temperature of hydrogen jet fires and prevent the fire from developing further. Increasing the average droplet size of the fine water mist results in a gradual degradation of the suppression effect, while a higher spray velocity of the mist enhances the suppression effect to a certain extent. The ambient wind speed is an important factor that influences the suppression effect of a fine water mist on hydrogen jet fires, and when this speed is less than 4 m/s, a fine water mist with a higher spray velocity and smaller average droplet size is still a superior way of suppressing fires.     

Experimental study on the effect of fan-shaped water mist on horizontal under-expanded hydrogen jet flames

A series of experiments were performed on the fan-shaped water mist interaction with the horizontal under-expanded hydrogen jet flames. The effects of various water mist pressures and horizontal release positions were focused on flame length, temperature, and radiant heat flux. The results show that, water mist causes the flame to be tilted and the tilt angle of the flame increases with the water mist pressure, and the horizontal length of the flame is shortened. It is also found that water mist may lead to the radiation and temperature enhancement on the axis and downstream of the action position of water mist and flame, which is closely related to the configuration of water mist. However, this situation disappears and the temperature and radiation decrease with the increase of water mist pressure.