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published in(发表于) 2016/6/25 11:59:29
The long seventh rocket “ice fire“

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The long seventh rocket "ice fire"
Xinhua News Agency, Hainan, Wenchang June 25 (reporters Zeng Tao and and Chen Xi and and Wang Yushan)-new generation medium-launch vehicles at the long seventh fuel with liquid oxygen and kerosene, the rocket fuel storage and heat treatment after ignition put forward higher requirements. Aerospace Science and Technology Corporation technician Academy of launch vehicle technology said, deal with the very low fuel tank temperatures and the rockets the ultra high temperature of the flame, the "ice fire" is one of the important technology of rocket launches.
  Long seventh "ice": the temperature of the fuel is extremely low, raise store about
Prior to launch, long seventh to complete the 170 cubic meters of kerosene and 340 tonnes of liquid oxygen filling. Among them, the temperature reached lingxia183sheshidu of liquid oxygen. Storage tank of liquid oxygen, using mechanical milling process, chemical milling process tanks are more lightweight than in the past, environmental protection and pollution-free. Meanwhile, tanks manufactured by adiabatic process, in the vacuum between the various layers to ensure the tank the "cold" effect.
Liquid nitrogen is not one of the fuel, but it also plays an important role in the rocket. Before fueling, launch site staff to use liquid nitrogen to purge the fuel pipeline. Because liquid nitrogen temperature lower than the liquid oxygen, liquid nitrogen purge pipe not only reduces the cost, but also more effectively and quickly to cool the pipes.
Hainan Wenchang satellite launching site filling team leader Zhang Ji's introduction, when they raise need to wear protective clothing and gloves. Liquid oxygen and liquid nitrogen delivery will produce a lot of noise, they also wear a noisy earplugs. Connecting pipe of the long seventh and filling stations reach more than 5,000 meters, valves, 214, raise staff workload is very large.
12 hours before the rockets start to raise kerosene, this process lasts approximately 4 hours. Subsequently, 3 liquid oxygen storage tanks split, to raise the 6 modules. Reporters noted that the Lox station has 4 liquid oxygen tank. Zhang JI explained that 1 do not directly raise, but the addition of 3 oxygen filling pressure.
At the beginning of lox, to cooling your tank. In front of the tank temperature is not less than lingxia183sheshidu, and discharge all the liquid oxygen, not to be stored. Fuel tank temperature and pressure values are being monitored in real time and displayed on the filling control system.
Filling of liquid oxygen to last about 8 hours, the entire filling procedure until 2 minutes before ignition will end.
  Long seventh "fire": the flame temperature is extremely high, insulated cooling means
Reason long seventh to go through "ice fire", is because after the moment of ignition, the fuel will become more than 3,000 of the more than 100 degrees Celsius below zero degrees Celsius the flames, instant conversion to fire ice.
In the commanders ' release 7.4 seconds after ignition instructions, rocket's tail moment spewed a huge flame. Deputy Chief Designer long seventh launch vehicle introduced Hu Xiaojun, because fuel, belched flame color orange as ever, but is white, the vent gas temperature is much higher than in the past, making the launch platform moments close to 3,000 degrees Celsius.
The temperature enough to melt most metals and non-metals, rocket-launching platforms and arrow itself withstand such high temperatures. Launch pads and rocket boosters, the core level, are painted with exothermic coating. Two or three centimeters thick coating of heat more than 10 layers, every painting is different, and only a few millimetres of thickness, processing is very difficult. In addition, on the rocket boosters and the core stage, also with flexible insulation, which can further enhance the effect.
Xiaojun Hu introduce, rocket flight speed, also produces heat, resulting in arrows of the heat flux density increases. Easy to understand, is the increased heat of rocket surface within a certain time, which have higher requirements for materials of rocket bodies. At the long seventh in the manufacture of rockets, they learn from other processes, using a thermal efficiency of better material.
In addition, the long seventh rocket launch tower with a capacity of 600 tons of water tank, hooked up the water and set aside. This is currently on the international State of the art "high-flow water cooling and noise reduction system." According to Chen Jinsong, head of technology of the system introduced, rockets to arrows after getting to 5-meter-high Center of the body and tail of flame spray, two-stage Jet water jet for more than 20 seconds, completing 400 tons of water spray.
Injection of 400 tons of water, 30% water will vaporize into the atmosphere, 60% water flow away through the diversion channel, water evaporation took a lot of heat, launch platform core cooling rate at around 1000 degrees Celsius. In addition, the system would also have good noise reduction effect.
Author: Zeng Tao Chen Wang Yushan (source: Xinhua)
(Editors: Pan Yi burn UN657)
2016-06-25 21:06:35
China News Network
长征七号火箭的“冰火两重天”
新华社海南文昌6月25日电 (记者曾涛、陈曦、王玉山)新一代中型运载火箭长征七号在燃料使用上以液氧和煤油为主,这就对火箭的燃料加注贮存以及点火后的高温处理提出了更高要求。航天科技集团运载火箭技术研究院的技术人员称,处理好燃料贮箱的极低温度与火箭火焰的超高温度这个“冰火两重天”,是火箭发射的重要工艺之一。

  长征七号之“冰”:燃料温度极低,加注贮存有讲究

  在发射之前,长征七号要完成170立方米的煤油和340吨液氧的加注。其中,液氧的温度达到了零下183摄氏度。存储液氧的贮箱,采用机械铣工艺,较以往化学铣工艺的贮箱更加轻质化、环保无污染。同时,贮箱的制造采用绝热工艺,在各层之间抽真空,保证了贮箱的保“冷”效果。

  液氮虽然不是燃料之一,但是它在火箭发射中也起到了重要作用。在燃料加注前,发射场的工作人员要用液氮对燃料管道进行吹除。因为液氮的温度比液氧还低,用液氮吹除管道不仅降低了成本,还能更加高效快速地为管道降温。

  据海南文昌卫星发射场加注团队负责人张继介绍,他们在加注时需穿防护服、戴手套。液氧液氮输送时会产生大量噪音,他们还要戴上高噪音耳塞。连接长征七号与加注站的管道达到5000多米,阀门有214个,加注人员工作量很大。

  火箭发射前12个小时,要开始加注煤油,这个过程大约要持续4个小时。随后,3个液氧储罐各分两路,对6个模块进行加注。记者注意到,在液氧加注站,有4个液氧储罐。张继解释,有1个不直接进行加注,而是对另外3个氧灌进行增压。

  在液氧加注初期,要对贮箱进行预冷。在贮箱的温度未低于零下183摄氏度前,所有的液氧都将排放出去,不被贮存。燃料贮箱的温度和压力值,都实时被监测并显示在加注控制系统上。

  液氧的加注要持续将近8个小时,整个加注程序一直到点火前2分钟才会结束。

  长征七号之“火”:火焰温度极高,隔热降温多手段

  之所以说长征七号要经历“冰火两重天”,是因为在点火一瞬间之后,零下100多摄氏度的燃料就将变成3000多摄氏度的热焰,瞬间完成冰到火的转化。

  在指挥员下达点火的指令7.4秒之后,火箭的尾部瞬间喷出巨大火焰。长征七号运载火箭副总设计师胡晓军介绍,因为燃料不同,喷出的火焰颜色不像以往的橘红色,而是呈白色,喷口燃气的温度也比以往火箭高得多,使得发射平台瞬间接近3000摄氏度。

  这个温度足以熔化绝大多数金属和非金属材料,火箭发射平台和箭体本身都难以承受如此高的温度。在发射平台和火箭助推器、芯级上,均喷有放热涂层。两三厘米厚的防热涂层分为十几层,每一次喷涂都是不同材质,且厚度只有几毫米,工艺处理难度非常大。另外,在火箭助推器和芯级上,还贴有柔性隔热毡,它能进一步提升隔热效果。

  胡晓军介绍,火箭飞行速度快,也会产生热量,导致箭体的热流密度增大。通俗理解,就是一定时间内通过火箭表面的热量增多,这就对火箭箭体的材质有更高要求。在长征七号火箭的制造中,他们还借鉴其它工艺,采用了承热效能更好的材质。

  除此之外,长征七号火箭发射塔还装有一个能容纳600吨的水箱,装好了自来水备用。这就是目前国际上先进的“大流量喷水降温降噪系统”。据这个系统技术负责人陈劲松介绍,在火箭飞到5米高以后向箭体尾部火焰中心喷水,两级喷水设施各喷20余秒,完成400吨的喷水量。

  喷射的400吨水中,有30%的水会汽化到大气中,60%的水则通过导流槽流走,水分蒸发带走大量的热,发射平台核心区降温幅度在1000摄氏度左右。此外,这个系统还有良好的降低噪音效果。

  作者:曾涛 陈曦 王玉山 (来源:新华网)
(责任编辑:潘奕燃 UN657)
2016-06-25 21:06:35
中国新闻网




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