In order to develop further the application of high temperature heat pipe in hypersonic vehicles thermal protection, the principles and characteristics of high temperature heat pipe used in hypersonic vehicles thermal...In order to develop further the application of high temperature heat pipe in hypersonic vehicles thermal protection, the principles and characteristics of high temperature heat pipe used in hypersonic vehicles thermal protection were introduced. The methods of numerical simulation, theory analysis and experiment research were utilized to analyze the frozen start-up and steady state characteristic of the heat pipe as well as the machining improvement for fabricating irregularly shaped heat pipe which is suitable for leading edge of hypersonic vehicles. The results indicate that the frozen start-up time of heat pipe is long （10 min） and there exists large temperature difference along the heat pipe （47 ℃/cm）, but the heat pipe can reduce the temperature in stagnation area of hypersonic vehicles from 1 926 to 982 ℃ and work normally during 1 000-1 200℃. How to improve the maximum heat transfer capability and reduce the time needed for start-up from frozen state of the heat pipe by optimizing thermostructure such as designing of a novel wick with high performance is the key point in hypersonic vehicles thermal protection of heat pipe.展开更多
The Embankment with Crushed-Stone Slope Protection(ECSSP) in permafrost regions is an effective measure to cool subgrade and protect permafrost.It can mitigate the engineering hazards of the Qinghai-Tibet railway in t...The Embankment with Crushed-Stone Slope Protection(ECSSP) in permafrost regions is an effective measure to cool subgrade and protect permafrost.It can mitigate the engineering hazards of the Qinghai-Tibet railway in the permafrost regions. Considering the influence of the noctumal cold air during summer months in Qinghai-Tibet Plateau。展开更多
引信热防护技术与等效试验技术是提升引信快速烤燃安全性与热防护多轮优化设计效率的关键。根据引信一维热传导模型,构建炸药及引信壳体径向温度分布方程,建立基于铝-硅气凝胶的航空炸弹引信热防护模型,通过引信快速烤燃仿真模拟研究,...引信热防护技术与等效试验技术是提升引信快速烤燃安全性与热防护多轮优化设计效率的关键。根据引信一维热传导模型,构建炸药及引信壳体径向温度分布方程,建立基于铝-硅气凝胶的航空炸弹引信热防护模型,通过引信快速烤燃仿真模拟研究,获得引信内部炸药经历20 min 800℃烤燃环境的温度变化曲线。隔铝-硅气凝胶的临界厚度为3 mm,炸药最终温度比其5 s爆发点(280℃)低87.8℃,可以保证引信的热安全性。以铝-硅气凝胶包覆的引信为验证主体,结合快速烤燃标准试验方法建立基于仿真分析-高温火焰喷射试验平台的引信快速烤燃等效试验方法。试验结果表明,标准试验的引信易损点测温数据与仿真数据对比,精度优于91%;等效试验下引信易损点测量温度与标准试验测量结果对比,精度优于95%。试验结果表明,标准试验的引信易损点测温数据与仿真数据对比,标准试验精度优于91%;等效试验下引信易损点测量温度与标准试验测量结果对比,等效试验精度优于95%。展开更多
基金Project(51076062) supported by the National Natural Science Foundation of China
文摘In order to develop further the application of high temperature heat pipe in hypersonic vehicles thermal protection, the principles and characteristics of high temperature heat pipe used in hypersonic vehicles thermal protection were introduced. The methods of numerical simulation, theory analysis and experiment research were utilized to analyze the frozen start-up and steady state characteristic of the heat pipe as well as the machining improvement for fabricating irregularly shaped heat pipe which is suitable for leading edge of hypersonic vehicles. The results indicate that the frozen start-up time of heat pipe is long （10 min） and there exists large temperature difference along the heat pipe （47 ℃/cm）, but the heat pipe can reduce the temperature in stagnation area of hypersonic vehicles from 1 926 to 982 ℃ and work normally during 1 000-1 200℃. How to improve the maximum heat transfer capability and reduce the time needed for start-up from frozen state of the heat pipe by optimizing thermostructure such as designing of a novel wick with high performance is the key point in hypersonic vehicles thermal protection of heat pipe.
文摘The Embankment with Crushed-Stone Slope Protection(ECSSP) in permafrost regions is an effective measure to cool subgrade and protect permafrost.It can mitigate the engineering hazards of the Qinghai-Tibet railway in the permafrost regions. Considering the influence of the noctumal cold air during summer months in Qinghai-Tibet Plateau。
文摘引信热防护技术与等效试验技术是提升引信快速烤燃安全性与热防护多轮优化设计效率的关键。根据引信一维热传导模型,构建炸药及引信壳体径向温度分布方程,建立基于铝-硅气凝胶的航空炸弹引信热防护模型,通过引信快速烤燃仿真模拟研究,获得引信内部炸药经历20 min 800℃烤燃环境的温度变化曲线。隔铝-硅气凝胶的临界厚度为3 mm,炸药最终温度比其5 s爆发点(280℃)低87.8℃,可以保证引信的热安全性。以铝-硅气凝胶包覆的引信为验证主体,结合快速烤燃标准试验方法建立基于仿真分析-高温火焰喷射试验平台的引信快速烤燃等效试验方法。试验结果表明,标准试验的引信易损点测温数据与仿真数据对比,精度优于91%;等效试验下引信易损点测量温度与标准试验测量结果对比,精度优于95%。试验结果表明,标准试验的引信易损点测温数据与仿真数据对比,标准试验精度优于91%;等效试验下引信易损点测量温度与标准试验测量结果对比,等效试验精度优于95%。
