双燃料发动机油雾-燃气混合探测装置研制

针对传统的柴油机油雾探测器只能探测颗粒状油雾质量浓度,而传统的可燃气体探测器只能探测气态介质的体积分数,开发了一款新型双燃料发动机油雾-燃气混合探测器。该装置能够同时探测油雾质量浓度和燃气体积分数,并且可在不同混合比例下按不同的爆炸极限进行报警。     

小粒径油雾发生装置研制

针对现有的油雾发生装置油雾粒径(7~40 μm)不符合中国船级社《钢制海船入级规范》关于油雾发生装置油雾粒径不得超过5 μm的规范要求,研制了一种小粒径油雾发生装置。经测量验证:所研制的油雾发生装置油雾粒径可控制在5 μm以内，并能控制油雾浓度、雾化温度及油雾流量，可为油雾探测器研制提供平台试验条件。     

柴油机曲轴箱油雾探测装置研制

所述油雾探测装置系利用光透射原理设计,主要包括光路、电路、气路三部分,并设计了标定系统对试验过程进行监测。试验表明：该装置能够实时反映油雾浓度的变化,在必要时能及时发出报警信号,满足柴油机曲轴箱对油雾探测装置的性能要求。     

新型油雾探测器的光路设计

为解决现有曲轴箱油雾探测器普遍存在的油雾测量室体积大的问题,并在原型油雾探测器的基础上提高测量准确度和精度, 设计了一种新型油雾探测器。该油雾探测器利用红外分光光度法原理测量油雾浓度。平台试验结果表明:与原型油雾探测器相比，采用新光路设计的油雾探测器测量室体积大幅减小，测量准确度和精度均有所提高。     

新型油雾探测器测量室的仿真及优化设计

针对某型油雾探测器的测量室，分别从油雾采样时间、油雾过滤迷宫、探测头新鲜空气吹扫气路等方面开展仿真计算，根据仿真结果对测量室进行优化设计并通过试验验证优化设计的效果。优化后的油雾探测器满足中国船级社的相关规范要求。     

细水雾与油雾火焰相互作用的实验及数值模拟研究

开展了细水雾抑制熄灭燃油油雾火的实验研究,并在试验研究的基础上,利用大型计算流体力学商业软件模拟研究细水雾与油雾火焰的相互作用。研究表明,细水雾熄灭油雾火的机理是降低可燃物与氧气混合浓度比和动力学效应、火焰冷却与衰减热辐射。在细水雾与油雾火焰相互作用动态过程中模拟计算与实验有一定程度的吻合;模拟计算表明细水雾有效灭火的前提是快速穿透火焰。     

曲轴箱油雾探测器研制过程中几个关键问题的分析

曲轴箱油雾探测器对保证机舱工作安全性意义重大。介绍了在研制过程中涉及到的关键技术,如油雾浓度的测量方法、波长及传感器的选择、油雾样品的制取、误差修正、减少误报警等,同时指出,开发过程应严格按照有关船规要求,避免在今后产业化过程中走弯路。     

大功率中速柴油机曲轴箱油雾爆炸分析

针对大功率柴油机电站主机曲轴箱油雾爆炸的部件损坏现象进行分析。分析表明：曲轴箱爆炸非运行不当,而为部件自身疲劳损坏引发。据此制定防范措施并加以执行,且执行情况也有效验证分析结果的可靠性。     

浅谈温度测量在油雾探测器中的应用

油雾探测器是柴油机工作状态监测的重要设备,针对油雾探测存在的误动作等问题,从油雾探测器的种类、工作原理出发进行分析,提出：将曲轴箱温度作为条件之一,加入油雾探测器的判断分析逻辑中,可降低误报警的出现,提高探测器的精度。     

机泵油雾润滑技术在某炼油厂的应用分析

联系油雾润滑技术在延安炼油厂的实际应用情况,从油雾润滑的机理、理论分析及使用效果等方面来说明油雾集中润滑方式具有极大的实用价值。     

Experimental research on hydrogen/air explosion inhibition by the ultrafine water mist

This experimental study focused on the inhibition of ultrafine water mist on hydrogen explosion inside the closed vessel. The inhibition law and mechanism were studied through changes of explosion intensity, flame propagation velocity and temperature under different mist concentrations. Results indicate that flame propagation and pressure rise inside the closed vessel were corresponding. Explosion intensity was reduced after adding mist, which was mainly manifested in the reductions of explosion pressure and flame propagation velocity. Flame was accelerated to extinguish and the inhibition effect was enhanced with increasing mist concentration. However, the explosion prussure did not present obvious reduction as the mist concentration reached a certain value. Besides, it indicates that the absoption heat effect of ultrafine water mist was an important factor on hydrogen explosion inhibition by the reductions of flame temperature and propagation velocity. The inhibition effect was mainly attributed to the combination effect of physical and chemical inhibitions.     

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.     

超细水雾作用下瓦斯的爆炸压力及升压速率

采用三面透明的长方体腔体模拟狭长空间内的瓦斯气体爆炸,研究了不同体积超细水雾对不同体积分数瓦斯气体爆炸的抑制作用.实验中采用GigaView高速摄影获取超细水雾抑制瓦斯爆炸的动态过程,采用两个PCB压力传感器测量超细水雾抑爆过程中腔内两个不同位置的压力变化情况.结果表明,瓦斯气体的爆炸压力、爆炸升压速率以及爆炸波的传播速度均随着超细水雾施加量的增加而明显降低.除爆炸被超细水雾完全抑制的情况外,爆炸波的传播速度可从接近声速下降到150,m/s,爆炸压力可降低78%,说明超细水雾抑制瓦斯爆炸是十分有效的.     

细水雾熄灭K类火灾的全尺寸模拟实验

利用ISO 9705全尺寸多功能热释放速率测试仪在开放空间研究了细水雾作用下K类火灾的发展过程,实验中对细水雾作用下食用油火的温度、热释放速率及烟气的主要特性参数变化规律进行了测量与研究,分析了预燃时间对灭火有效性的影响,系统地阐述了细水雾作用下K类火灾关键特性参数的变化规律．实验发现,细水雾可以有效地抑制K类火灾的发展,在其作用下火焰温度及热释放速率快速降低,并可以有效地冲刷烟气,降低一氧化碳及二氧化碳的浓度,提高氧气的浓度及火场能见度．同时利用稳定火源热释放速率模型计算了K类火灾发展阶段的热释放速率,与实验测量结果比较发现,模型可准确地预测K类火灾发展阶段的热释放速率的变化规律．     

Suppression effects of ultrafine water mist on hydrogen/methane mixture explosion in an obstructed chamber

The mitigation effects of ultrafine water mist on hydrogen/methane mixture explosions with hydrogen fraction (ϕ) of the range from 0% to 60% were experimentally studied in a vented chamber with obstacles. The spraying time, droplets size of water mist and the volume ratio of hydrogen were varied in the tests, and the key parameters that reflect the explosion characteristics such as the flame propagation imagines, flame propagation velocity, and explosion overpressure were obtained. The results show that the ultrafine water mist presents a significant mitigation effect on hydrogen/methane mixture explosions. The flame propagation structures are similar under the condition of without and with ultrafine water mist while the flame temperature is declined by the physical and chemical inhibition by ultrafine water mist. In addition, the mitigation effect increases with the increase of water mist flux. As a result, the maximum flame speed and overpressure of ϕ = 30% hydrogen/methane mixture explosion are declined by 33.3% and 58.4% under the condition of spraying for 2 min with 15 μm ultrafine water mist, respectively. Besides, the mitigation effects of ultrafine water mist on ϕ = 30% hydrogen/methane mixture explosion descends evidently with the increase of the droplets size of the range from 6 μm to 25 μm, which due to the easier evaporation and the greater total droplets surface area of the smaller water mist. However, the explosion mitigation effect of ultrafine water mist on the hydrogen/methane mixture actually descends with the increase hydrogen fraction.     

Hydrogen cloud explosion suppression by micron-size water mist

The primary purpose of this paper is to reveal the mechanism of suppressing hydrogen cloud explosion by micron-size water mist. On the basis of experimentally obtaining the characteristics of flame behavior and explosion pressure by changing equivalence ratio and water mist density, the physical and chemical mechanism of suppressing hydrogen cloud explosion is analyzed. The results indicated that with the increase of micron-size water mist density, the explosion-related parameters (including mean flame front speed, peak explosion pressure, peak rate of pressure rise and positive pressure impulse) of ER = 0.8 and ER = 1.0 decrease monotonously, the explosion-related parameters of ER = 2.0 increases firstly and then decreases which peak value is appeared at 26.73 g/m³. A considerable part of micron-size water mist is difficult to be completely evaporated in the reaction region, the temperature of combustion products region will be reduced due to subsequent continuous evaporation. In addition, the gasified micron-size water mist mainly interacts with H radicals through the elementary reactions of R3, R38 and R84. Due to incompletely evaporated micron-size water mist, the mist-induced turbulence is generated, which is the reason of enhancing hydrogen cloud explosion at lower micron-size water mist density of ER = 2.0.     

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.     

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%。