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雷电与飞机雷电与飞机的科技翻译How often are aircraft struck by lightning ?It is estimated that on average , each airplane in the U.S. commercial fleet is struck slightly more than once per year . In fact , aircraft often trigger lightning when flying through a heavily charged region of a cloud . In these instances , the lighting flash originates at the airplane and extends away in opposite directions .although record keeping is poor , smaller business and private airplanes are thought to be struck less frequently because they usually do not adhere to rigid schedules . 飞机遭受雷击的频率有多高？平均估计，美国的商业飞机机队中每架飞机每年都会遭受不止一次的轻微雷击。事实上，飞机在穿越电荷集中的云区时，经常会引起雷击。在这些事例中，闪电是在飞机上的某一点产生并从飞机上另外一点消逝。虽然有关闪电击中飞机这方面的记录不是很健全，但一般认为小型公务机和私人飞机被闪电击中的机率要小一些，因为它们通常不执行固定的计划航班。Does lightning cause aircraft to crash ?The last confirmed civilian plane crash that was directly attributed to lighting in the U.S. was in 1976 , when lightning caused a catastrophic fuel tank explosion . since then , much has been learned about how lightning can affect airplanes , and protection techniques have improved . Airplanes receive a rigorous set of lightning certification tests to verify the safety of their designs.闪电会导致飞机坠毁吗？1976年，在美国发生了闪电引发油箱爆炸并导致了一架民用客机坠毁的灾难性事件，这是距今最近的一起闪电引起的飞机坠毁事故。从那时起，人们更多地认识到了闪电是如何影响飞机的，同时保护性的技术措施也得到了改进。飞机要接受一系列严格的防雷测试以证明设计的安全性。What happens when an aircraft is struck by lightning?Although passengers and crew may see a flash and hear a loud noise , nothing serious should happen because of the careful lighting protection engineered into the aircraft and its sensitive components. Initially , the lightning will attach to an extremity , such as the nose or wing tip . the airplane then flies through the lightning flash , which reattaches itself to the fuselage at other locations while the airplane is in the electric ‘circuit’ between the regions of opposite polarity . the current will travel through the conductive exterior skin and structures of the aircraft and exit off some other extremity , such as the tail . pilots occasionally report temporary flickering of lights or short-lived interference with instruments . We have heard reports of the activation of cabin oxygen masks ; no doubt frightening for the passengers .闪电击中飞机时究竟发生了什么变化？尽管有时候机组和乘客看到了闪电，也听到了巨大的雷鸣，但是飞机并不一定受到严重的损坏，这主要是飞机本身和它的敏感元件事先都得到了仔细的雷电防护。开始时，闪电会从飞机上的一个尖端部位切入，如机头和翼尖。接着整架飞机会飞入闪电区，这样飞机就处于两个相反极性的闪电回路中，此时闪电会重新附着在机身其他部位上。闪电电流会流经机身导电层和飞机结构并从飞机的其他尖端流出，如飞机尾部。飞行员偶尔会报告在飞行过程中短暂的灯光闪烁或短时的仪表干扰；我们也听说过一些客舱氧气面罩被激活的报告。对乘客来说，这无疑是令人恐惧的。How is an aircraft protected from lighting ?飞机如何防雷击？Most aircraft skins are made primarily of aluminum.… By making sure that there are no gaps in this conductive path , the engineer can assure that most of the lightning current will remain on the exterior skin of the aircraft . some modern aircraft are made of advanced composite materials , which by themselves are significantly less conductive than aluminum . In this case , the composites are made with an embedded layer of conductive fibers or screens designed to carry lighting currents . these designs are thoroughly tested before they are incorporated in an aircraft .大多数的飞机蒙皮主要是铝质的…。工程师在确信导电通路上没有间隙后，便可以判定绝大部分的闪电电流是在飞机的外表面。一些现代飞机是由先进的复合材料制成的，它们比铝的导电性要差。这种情况下，制造复合材料时就要夹入一层导电光纤或导电屏，以便传导闪电电流。这些设计在运用到飞机上之前已经经过了全面仔细的测试。Modern passenger jets have miles of wires and dozens of computers and other instruments that control everything from the engines to the passengers’ music headsets . these computers , like all computers are sometimes susceptible to upset from power surges . so , in addition to the design of the exterior of the aircraft , the lightning protection engineer must assure that no damaging surges or transients can be induced into the sensitive equipment inside of the aircraft . lightning traveling on the exterior skin of an aircraft has the potential to induce transients into wires or equipment beneath the skin . these transients are called lightning indirect effects . problems caused by indirect effects in cables and equipment are averted by careful shielding ,grounding and the application of surge suppression devices when necessary . Every circuit and piece of equipment that is critical or essential to the safe flight and landing of an aircraft must be verified by the manufactures to be protected against lighting in accordance with regulations of the FAA or a similar authority in the country of the aircraft’s origin .现代喷气式客机都拥有数公里长的导线、成打的计算机和其他设备，他们可以控制所有事情，大到发动机，小至乘客音乐耳机。同所有的计算机一样，这些计算机都对电流波动较为敏感。因此，在设计飞机外围时，防雷电工程师要确保不会有破坏性或瞬间电流引起飞机内敏感设备损坏。闪电流过飞机外部蒙皮时会引起线路或飞机内设备产生强大的感应电流。这些感应电流被称为‘闪电间接效应’。消除‘闪电间接效应’引起的电缆及设备损坏，可以通过‘屏蔽’或‘接地’方式，必要时甚至可以采用‘镇流装置’法。根据FAA规章或航空器制造国适航部门规章要求，每一个密切关系飞机安全飞行和安全着陆的部件，它的内部电路和模块要由制造商验证可以防闪电干扰。The other main area of concern is the fuel system , where even a tiny spark could be disastrous .Therefore , extreme precautions are taken to assure that lightning currents cannot cause sparks in any portion of an aircraft’s fuel system .The aircraft skin around the fuel tanks must be thick enough to withstand a burn through . All the structural joints and fasteners must be tightly designed to prevent sparks as lightning current passes from one section to another . Access doors , fuel filler caps and any vents must be designed and tested to withstand lighting . All the pipes and fuel lines that carry fuel to the engines , and the engines themselves , must be verified to be protected against lighting . In addition , new fuels that produce less explosive vapors are now widely used .另一个备受关注的区域就是燃油系统，任何一个微弱的电火花都可能引起灾难性后果。因此，必须提高警惕以确保闪电电流在飞机燃油系统的任何部位都不会产生电火花。油箱附近的机身蒙皮要足够厚，要可以耐受燃烧的高温。机身结构上的结合处和紧固件要严格设计，避免闪电电流流过时产生电火花。一些接近门，燃油加油口盖和一些通气口都要通过防闪电设计和测试。所有输送燃油到发动机的管路和燃油管，以及发动机自己的管路都要能够防雷电。另外，现在广泛使用了一种产生较少爆炸性蒸汽的新型燃油。Radomes are the nose cones of aircraft that contain radar and other flight instruments . The radome is an area of special concern for lighting protection engineers . In order to function , radar cannot be contained within a conductive enclosure . Protection is afforded by the application of lightning diverter strips along the outer surface of the radome . These strips can be solid metal bars or a series of closely spaced buttons of conductive material affixed to a plastic strip that is bonded adhesively to the radome . these strips are sized and spaced carefully according to simulated lightning attachment tests , while at the same time not significantly interfering with the radar . In many ways , diverter strips function like a lighting rod on a building .雷达罩是飞机的头锥，它里面安装有雷达和其他飞行仪表设备，雷达罩对防雷电工程师来说是涉及雷电的特殊区域。雷达功能要求，它不能工作在导电的舱罩内。防护是通过使用沿着雷达罩外表面的闪电分流条实现的。这些分流条可以是固态金属条，也可以是粘在塑料条上的一系列紧密排列的导电点，分流条粘结在雷达罩上。通过模拟雷电接入试验，保证雷达不受雷电干扰，这些分流条被设计成标准的大小并按一定的间距精确地排列。在许多方面，分流条的作用就像建筑物的避雷针。 |
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发表于 2010-11-8 08:58:39
