军用电子机箱的热分析与热设计.pdf

西安工业大学
硕士学位论文
军用电子机箱的热分析与热设计
姓名:向广超
申请学位级别:硕士
专业:机械工程
指导教师:马保吉;段生记
20080512
军用电子机箱的热分析与热设计
学科:机械工程
研究生签字:〈听起
指导教师签字:
摘要
任何电子设备均处于一定的环境条件下生产、运输、储存和使用。这些环境包括:气
候、机械、电磁、生物、化学以及特种环境等。在这些环境因素的作用下,如不采取有效
的环境保护措施,将导致电子设备或系统功能的降低、失效或损坏。而诸多环境因素中,
气候因素中的温度(高、低温及其循环),对电子设备或系统的影响,尤为人们所关注。
大量事实证明,热设计不当是导致军用电子产品失效的重要原因之一。实践表明,电
子元件的故障率随元件温度的升高呈指数关系增加,电子设备线路的性能则与温度的变化
成反比。在严酷的气候条件下,特别是高温高混和盐雾或大量工业气体污染等恶劣环境中,
雷达设备中的金属材料特别容易遭受腐蚀:;非金属材料也易老化和霉变,从而严重影响电
子设备的可靠性和寿命
某海防雷达,工作于高温高湿地区,要求有良好的环境适应性。位于操控舱内的某密
闭机箱,不仅受到操控台结构尺寸的限制,而且箱体内有电源,CPU等高热器件,因此,
该机箱的热设计与防护性设计成为一个突出的矛盾。本文介绍了对该密闭电子机箱的热设
计与热分析计算,并通过仿真软件对温度场进行了计算分析和优化设计。
文中介绍的密闭机箱的结构方式为以气冷式冷板作为密封式电子机箱的侧壁,再用强
迫风冷的方式将侧壁上的热量带出机箱,同时在机箱电连接器及盖板四周加装密封导电衬
垫,实现了机箱与外界环境的彻底隔绝,有效地解决了机箱的密闭和散热问题。这种结构
方式实现了机箱内元器件不与潮湿空气相接触,避免了海上恶劣气候条件对设备造成的直
接危害,该机箱目前已通过了高、低温试验,及冲击振动等一系列例行试验,证明这种以
气冷式冷板作为机箱侧壁的结构形式,其刚强度设计和热设计是合理和有效的。本工程的
设计将会为其他同类电子设备的热控制提供有益的借鉴。
关键词:电子设备;密闭机箱;热分析;热设计;热控制
Thermal analysis and design of a military electronic cabinet
Discipline: Mechanical Engineering
Student Signature: Xiang gue
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Supervisor Signature: /wwwi: Duo heg )a
Abstract
Any electronic device is manufactured, transpor ed, stored and used in some environments
which include weather, mechanical, electromagnetic, biological, chemical and special
surroundings. Effects of these environmental factors will lead to functional decrease, failure or
damage of the electronic device or system if effective measures are not taken. Among all these
factors, the temperature factor (high, low temperature and its circulation of the weather factors
has significant influence on the electronic devices or systems and hence needs to be studied
specially.
Numerous facts show that improper thermal design is one of key reasons causing failure of
military electronic products. Practices prove that the rate of failure of electronic components
increases exponentially as their temperature increase while the performance of the electronic
circuitry is inversely proportional to the change of temperature. The metallic materials used in
radars are very vulnerable to rust in adverse weather conditions, especially in an environment
with higher temperature and salty fog, or volumes of industrial gas pollution, The non-metallic
materials easily get aged or fungus in such surroundings, thus the reliability and service life of
electronic devices will be affected seriously
A coastal defence radar is used in an area with high temperature and humidity and is
required to have a good environmental adaptability. A closed cabinet placed in the operation
control shelter is limited by structure dimension of the console not only, but also some
heat-generating devices, such as a power supply and a CPU are mounted inside. Therefore, the
thermal design and protection design of this cabinet forms a conspicuous contradiction. This
paper introduces a thermal design and analysis calculation of this closed electronic cabinet
Calculation analysis and optimal design of its emperature field is made by simulation software
The structure of this closed cabinet takes the air-cooled plates as the side walls of closed
electronic cabinet and the heat of these walls is exhausted by using forced air cooling. In