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。     

油雾探测器应用于大功率柴油机的重要性

通过实际案例说明了油雾探测器应用于大功率柴油机运行的重要性。介绍了油雾探测器的工作原理和正确使用。     

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。     

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。     

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。     

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。     

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。     

水轮发电机组下导轴承油雾成因分析

为了研究水轮发电机组下导轴承油雾成因和机理,设计了抑制油雾逸出的新型轴承结构。运用VOF两相流模型和SST k-ω湍流模型,基于有限差分法,从流场特性、温度特性和相分布等方面分析了轴承油雾形成的原因和流动特性。结果表明：下导轴承的油雾形成主要与轴承结构相关;轴领内外两侧空腔的巨大压力差为油雾的逸出提供了驱动力,下导轴承挡油管缺乏密封结构,巨大空腔为油雾提供了逸出通道,最终导致油箱油雾大量逸出;轴瓦与轴领的摩擦生热导致部分润滑油气化形成气态油雾,油雾从轴领与挡油管之间的空腔散发出去。     

立式水轮发电机组轴承油雾的治理

常规立式水轮发电机组轴承在运行时容易出现油雾外溢的问题,该问题对很多水电站都曾造成过困扰。本文对油雾产生的原因进行了分析,介绍了多种防油雾结构并指明其优缺点,指出了油雾治理的难点和常见误区,为立式水轮发电机轴承油雾的治理提供了借鉴。     

小浪底电厂发电机轴承油雾研究与治理

为解决小浪底电厂6台水轮发电机组轴承油雾问题,对轴承的结构、油位、温度、渗漏、内部油循环情况进行了分析,从油雾的消减、密封和收集入手,采取了降低轴承油位、改进轴承结构、增加密封装置等一系列有效措施,成功地解决了轴承油雾问题.经现场运行检验,效果非常明显.     

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。     

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.     

柴油机迷宫式油气分离器分离效率数值模拟

应用商用CFD软件AVL-FIRE对某三缸柴油机迷宫式油气分离器进行CFD分析,模拟迷宫内的流速与压力分布;采用离散模型模拟油滴粒子喷射,假定油滴粒子与壁面碰撞后即被捕捉,进而得出不同直径的油滴分离效率;对比了几种迷宫结构方案的进出口压降以及油气分离效率。结果显示:计算结果虽偏高,但趋势与试验值较吻合,证明了采用CFD技术对油气分离器进行模拟的可行性。     

船舱中油的存在状态及危害分析和预防措施

介绍了船舱中油的主要存在状态包括:液态油、油烟、油雾、喷雾等。当油雾或喷雾的浓度增大到一定程度时,有引起火灾和爆炸的危险。主要预防措施可以安装油雾探测装置(OMD),OMD可通过检测油雾的浓度并发出报警信号来预防爆炸的发生。     

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．     

一种新型气密封防油雾装置及其应用

针对目前机组防油雾密封问题,介绍了一种新型的气密封防油雾装置,该装置采用机组自身旋转产生的气压对机组的油雾进行有效密封,其主要结构由气密封盖、进气腔、高压进气管道、低压排气管道及冷凝器等组成,并将该装置应用于那邦水电站发电机中。实例应用结果表明,该装置不仅可自动平衡油槽内外的气压,还能有效将油雾进行疏导、收集并净化,且结构简单、成本低廉、便于安装和维护。     

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.     

Experiment and prediction of fire extinguishment with water mist in an enclosed room

The correlation between oxygen concentration and fire temperature when fire was extinguished with water mist was theoretically studied. The Semenov theory was applied to analyze the critical condition when fire was extinguished with water mist, from which the correlation could be obtained. The water mist experiments were carried out by varying the fire size, atomizer number, ceiling height, system pressure, and pre-burn time in an enclosed room. The oxygen concentration near the edge of the liquid pool and the fire temperature above the center of the liquid pool were measured. A comparison of the experimental data with the correlation was made under different conditions. The results showed that fire extinguishment was a stochastic process which could be affected by many factors. This theoretical model could predict the correlation between fire temperature and oxygen concentration when fire was extinguished with water mist in an enclosed room and it can also be treated as a critical condition for fire extinguishment.