【作者】 朱仁胜；

【导师】 赵韩；

【作者基本信息】 合肥工业大学 ， 机械设计及理论， 2016， 博士

【摘要】 本课题来源于中国航空工业集团公司产学研合作项目:复杂大气环境条件下气囊气密性检测方法。主要针对中国特种飞行器研究所浮空气囊进行气密性检测方法研究。气密性是浮空器一项重要的技术指标,它关系着浮空器安全、留空时间及使用成本。然而,气囊气密性的检测,尤其是复杂大气环境温度变化下浮空气囊气密性检测是一项难点。传统的办法是对气囊内部充空气使其压强超过外界大气压强,然后,检测某一段时间内气囊内部与外界大气压强差的变化值,利用理想气体状态方程,推导气囊内部气体泄漏量。但考虑到外界温度、太阳辐射等环境变化,会对气囊内部气体产生影响,从而对气囊内部与外界大气压强差产生影响,其影响量甚至大于气囊内气体泄漏本身产生的影响。因此,需要开展复杂大气环境温度变化的气囊气密性检测方法研究。旨在找到泄漏量与环境温度及压差变化之间的关系,建立数学模型,从而计算出气囊的泄漏量。本文的主要研究工作和成果总结如下:1、为了解决实际浮空气囊尺度太大,几千立方米到几十万立方米,建立实际气囊检测平台不现实,故通过有限元仿真方法开展研究,首先对蒙皮热特性进行了研究,其次对无泄漏浮空气囊不同工况下定点过程、不同海拔高度和升空过程中的热特性进行了研究,得出任意时刻浮空气囊热特性的分布规律。2、研究了直径1.5m浮空气囊泄漏热特性,即在不同工况下浮空气囊内外压差、内部气体密度和内部气体温度分布及随时间变化的规律,并研究壁面温度恒定条件下气囊泄漏热特性,建立了浮空气囊泄漏量与温度及压差变化之间的关系式。并外推到一款直径50m的实际浮空气囊泄漏仿真计算。3、研究了浮空气囊的充气和放气特性。针对现有的检测方法不能满足浮空气囊的泄漏检测,提出了定量泄漏检测方法,并申请发明专利获得授权(专利号:2013107391232),该方法首先通过对模型气囊在不同温度及压差变化下一段时间内的泄漏量进行仿真计算,将其数据进行数学建模,得到泄漏量和其温度、压差变化之间的关系式;然后搭建实验平台建立可控的泄漏通道,对不同泄漏量和温度及压差变化进行测量,进而得到大量的测量数据,利用这些数据对仿真模型进行验证和修正;进一步把仿真方法外推到任意实际气囊,可得到相应的数学模型,该模型只要测量实际气囊一段时间内温度及压差的变化就可精确计算浮空气囊的泄漏量。4、针对目前国内外尚无浮空气囊泄漏检测实验装置,基于浮空气囊定量泄漏检测方法提出了实验思路和实验平台方案,运用理论分析和数值模拟方法开发了一套新型的实验装置,并进行了气路系统设计、总控硬件设计及采集系统软件开发。同时对实验装置精度进行了分析及不确定度评定。并申请发明专利浮空气囊检漏试验台获得授权(专利号:2013107328563)和浮空气囊检漏试验台风源发生装置进入实审(专利号:2013107328332)。5、运用浮空气囊实验平台安排实验进一步研究浮空气囊泄漏问题。采用正交试验法安排环境温度T、初始压差P和泄漏时间t进行实验,对实验数据采用极差分析法,分析影响因素的显著性,并运用逐步回归方法建立了泄漏量与各项因素之间的最优回归方程。根据最优回归方程可以得出各因素和泄漏量之间的定量关系。实验平台在同仿真边界条件设置一样的情况下对气囊泄漏量进行测定,得出的实验数据和仿真数据进行比较,误差在5%以内,说明仿真方法正确,进一步证明了定量泄漏检测方法正确。更多还原

【Abstract】 The study is originated from industry-university research cooperation project of Aviation Industry Corporation of China: Investigation on Detecting Gas Tightness of Aerostat in Complex Surroundings. The study aims to find good methods to detecting quantitatively gas leakage of aerostat manufactured by Special aircraft Research Institute of China.Gas tightness is an important technical index for aerostat, which is related to the aerostat safety, loiter time and use cost. However, it is difficult to detect the gas tightness of aerostat, especially in the complex atmospheric surroundings. A traditional way is as follows: first, the air is filled into the aerostat so that the internal pressure of aerostat is higher than the atmospheric pressure; then the difference between the internal pressure of aerostat and atmospheric pressure is measured at certain time, finally the air leakage of aerostat is derived by use of ideal gas equation of state. But the traditional way is not good since atmospheric temperature, solar radiation, etc can affect both the internal pressure of aerostat and the pressure difference of internal and external aerostat.Sometimes these factors’ impact is even greater than the impact of gas leakage of aerostat. Therefore, it is necessary to study the gas tightness of aerostat in the complex atmospheric surroundings to find the factors which affect gas leakage,and establish a mathematical model by which can the leakage of aerostat can be calculated.This dissertation includes the following parts:1、The finite element model for aerostat balloon is created, and the numerical investigation on thermal characteristics of aerostat balloon at certain location and during floating without leakage is performed, then the numerical investigation on the same condition with leakage is performed.2、The gas leakage is numerically calculated at certain time at certain temperature and pressure change. In the end, the gas leakage of aerostat balloon is calculated by use of the mathematical model developed in chapter 2, and the results are verified by the numerical simulation developed in this chapter. and a lot of data collected are fused to fit the mathematical model by use of the controlled leakage method proposed in Chapter 4. which shows that the numerical simulation is reasonable.3、The inflation and deflation processes of gas in aerostat balloon are simulated, A new method——controlled leakage method for measuring leakage of aerostat balloon is put forward and the application for patent of invention based on it is granted (Patent No.:201310739123.2). More importantly, the multifunctional experiment devices are designed, the principle of which is as follows: a gas export valve is added in the balloon so that the leakage condition of aerostat balloon can be simulated by deflating gas.Because the gas deflation by export valve amplifies gas leakage effect of aerostat balloon, it is easier to build the mathematical model of the air leakage quantity.4、The gas leakage testing experiment platform for aerostat balloon according to the controlled leakage method proposed in Chapter 2 is established. The application for patent of invention named ’Gas Leakage Testing Experiment Platform for Aerostat Balloon(Patent Application No.: 2013107328563 )’ is granted and The application for patent of invention named ’Wind Generating Device for Leakage Testing Experiment Platform for Aerostat balloon’ based on the experiment platform is under substantive examination (Patent Application No.: 2013107328332 ). Moreover, the pneumatic system, controlling system and the software of data acquisition of experiment platform are designed and established. And the accuracy of the experimental device is analyzed and the uncertainty evaluation is made.5、The parameters during controlled leakage processes of aerostat balloon are measured by use of the gas leakage testing experiment platform,and a lot of data collected are fused to fit the mathematical model by use of the controlled leakage method proposed in Chapter 4. Moreover, the numerical simulation in Chapter 3 is verified by the experimental results, and the controlled leakage equation of aerostat balloon is derived. The comparison between both the experimental and numerical results are made,which shows that the numerical simulation is reasonable. Moreover,the numerical simulation in Chapter 3 is verified by the experimental results, and the controlled leakage equation of aerostat balloon is derived. The comparison between both the experimental and numerical results are made.更多还原