【作者】 王静立；

【导师】 朱玉泉；

【作者基本信息】 华中科技大学 ， 机械电子工程， 2005， 硕士

【摘要】 现代社会的发展和科学技术的进步,对抑制火灾的方法提出了更高的要求。哈龙灭火系统严重破坏大气臭氧层,将被全面禁止使用,寻找有效的替代技术已成为世界各国研究的焦点。高压细水雾灭火技术无污染、灭火效率高,已成为国际上公认的哈龙灭火系统的主流替代技术之一。喷嘴是各种类型高压细水雾灭火系统中必不可少的关键部件,因此,本课题关于喷嘴的雾化机理、雾化特性及其灭火性能的研究,对推动高压细水雾灭火技术在我国的发展和应用具有十分重要的意义。本文分析了高压细水雾灭火的机理和优越性。探讨了液体雾化的机理,通过对各种雾化装置的分析比较,选定了离心式喷嘴作为高压细水雾灭火系统的喷嘴形式。对离心式喷嘴的内部流场进行了理论分析,得出了对喷嘴的设计有一定的指导作用的结论。利用激光粒度仪对多种喷嘴进行了大量的雾化特性实验,结果表明:随着压力的增大,雾滴粒径减小,粒度分布更均匀;流量随着压力的增大而增大,但喷嘴的流量系数是基本不变的;在测试距离增大时雾滴的粒径有所增大,雾滴均匀度指数下降;喷射角较大时形成的雾滴粒径较小;雾滴粒径与喷孔直径的平方成正比。这些结论为喷嘴的设计及应用提供了依据。根据不同的应用要求,提出了不同类型的灭火系统方案,设计出了手提式高压细水雾灭火器初样机。用固定式灭火系统和手提式灭火器初样机进行了灭火性能试验,结果表明:高压细水雾灭火系统灭火性能良好,耗水量少,灭火迅速,对人员、设备基本不会产生危害。更多还原

【Abstract】 As development of morden society and advance of science & technology, methods to suppress and extinguish fire bring up the higher requirement. Halon will be banned by most countries worldwide due to its adverse effect on the ozone layer. It has brought the development of alternative fire-fighting methods into focus. In view of its significant advantages including environment-friendly, fast and effective fire suppression, etc., water mist fire extinguishing system has been recognized as the most potential substitute of halon fire-fighting system. Nozzle is a key component that is essential to all kinds of high-pressure water mist fire extinguishing systems. Therefore, research on nozzle’s atomizing mechanisms and characteristics and its fire suppression characteristics in this dissertation has great significance for the development and application of the high-pressure water mist fire extinguishing technology. The mechanisms and advantages of high-pressure water mist fire extinguishing technology are analysed. Atomizing mechanisms of liquid is discussed. After comparison of various atomizers, centrifugal nozzle is selected for the spray head used in the high-pressure water mist fire extinguishing systems. The inner flow field of centrifugal nozzle is theoretically analysed. Conclusions that are useful for the design of nozzles are deduced. Lots of experiments on the atomizing characteristics of several types of nozzles are carried out by the use of a laser particle size analyzer. The results show that: The increase of pressure can lead to the decrease of particle size and it is beneficial to particle size distribution. The increase of pressure can result in the increase of flux, but the flow coefficient of nozzle is constant. With the increase of measure distance, particle size of mist droplets becomes bigger. Meanwhile it decreases the coefficient of uniformity degree of mist droplets. The augment of spray angle can lead to the decrease of particle size. Particle size of droplets is in direct proportion to the square of the diameter of spout. These conclusions lay the foundation for the design and application of nozzles. Different extinguishing systems are proposed to meet various application requirements. The prototype of a portable high-pressure water mist fire extinguisher is designed. Experiments of fire suppression characteristics are carried out with fixed extinguishing systems and portable extinguisher. The results show that high-pressure water mist fire extinguishing systems perform well in extinguishing fires. It has advantages such as less water consume, fast and effective fire suppression, no harm to human beings and little damage to equipments.更多还原