远程传输型共底安全监测系统设计及特性

远程传输型共底安全监测系统是为满足当前火箭发射场自动化、高可靠性和缩短发射周期的需求,在原有火箭低温贮箱用共底安全监测系统基础上进行改进设计而研制的新一代安全监测系统。本文主要介绍了共底安全监测系统的历次设计变化情况,新一代远程传输型共底安全监测系统的主要结构及单元设计、性能与技术指标测试结果。     

液氧液甲烷同温共底贮存瞬态热力特性仿真研究

针对大面积冷屏保护下的液氧/液甲烷同温共底贮箱,建立了耦合真空多层绝热与主动制冷系统的瞬态传热模型,研究了液氧/液甲烷共底自增压与零蒸发贮存过程中贮箱外部绝热结构与内部气液相的热力参数变化规律,讨论了共底夹层采用不具有绝热能力的材料对液氧/液甲烷共底零蒸发贮存特性的影响。研究结果表明,在适当的冷量输入条件下,大面积冷屏方案可以实现外界漏热的有效阻挡;采用铝合金共底夹层有利于稳定液氧和液甲烷的共底贮存状态,使液氧/液甲烷在20 h内快速达到热平衡;在零蒸发贮存周期内,液氧/液甲烷共底贮存温度波动小于0.2 K,压力波动小于2.46 kPa且具有抗热扰动的能力。     

基于AMESim的贮箱增压过程仿真

某挤压式液体火箭发动机推进剂供应系统采取共底贮箱,增压过程中要求严格控制氧化剂箱和燃料贮箱的压差,防止贮箱中隔板破裂发生危险。利用AMESim软件,对该推进剂供应系统增压过程进行动态仿真,并进行系统地面增压试验,仿真结果与试验情况基本吻合。结果表明,在系统增压过程中,隔板压差在设计范围之内,能够保证贮箱安全、可靠工作。     

大型低温贮箱容积标定方法及不确定度评估

针对现有的大型低温推进剂贮箱标定要求,分析了大型贮箱容积标定常用的各种方法;阐述了标准围尺法/套管尺法的组合测量法容积标定技术,介绍了组合测量标定方法所需的计量器具、标定程序以及数据处理方法;给出了大型低温推进剂贮箱容积标定结果的不确定度评估。     

用于低温存储系统的多层绝热性能分析

真空多层绝热的性能好坏直接影响到低温贮箱的安全性。根据修正的Lockheed模型,计算冷边界温度、热边界温度、层密度等对均匀层密度多层绝热性能影响,并对三区域变密度的多层绝热性能进行分析,最后针对在轨、地面状态时对低温贮箱漏热方面的要求提出采用复合多层绝热的概念,得出复合多层绝热具有优良的隔热性能。     

国外单层共底贮箱的检漏

国外较多的运载火箭上，采用二种类型的单层共底贮箱存放Ｎ２Ｏ４（四氧化二氮）、ＵＤＭＨ（偏二甲肼）液体推进剂等。而对共底贮箱气密性泄漏检测，乌克兰＂旋风号一３＂二级共底贮箱采用大型真空罐真空法，法国＂阿里安１＂二级共底贮箱采用德国＂道尼尔公司＂研制的正压差累积法检漏。二种检漏方法的验收泄漏率均在１×１０－５Ｐａ·ｍ３／ｓ左右。     

火箭推进剂贮箱低温性能试验压力控制方法研究

为解决以往贮箱低温综合性能试验中压力控制精度不高的问题,通过研究贮箱低温综合性能试验中介质变化情况,根据现有试验条件,提出一种贮箱低温综合性能试验高精度压力控制方法,通过多次试验应用,达到了消除贮箱低温综合性能试验过程中由于低温介质的蒸发和冷凝引起的压力波动的效果,从而有效地提高了贮箱低温综合性能试验压力控制精度。     

液体火箭冷氦增压系统低温试验研究

为研究液体火箭低温氦增压系统中电磁阀与孔板组合方式的增压性能和优化孔板的设计,开展了使用液氢温区的氦气作为增压介质的冷氦增压系统试验,并通过排放液氧模拟火箭贮箱内液氧的消耗.通过分析试验过程中增压氦气流量和贮箱压力的情况,获得了该增压方式对贮箱的增压性能.试验结果表明电磁阀与孔板组合能将贮箱压力维持在设计范围内,是一种简单、可行的液体火箭液氧贮箱增压方案.     

致密化液甲烷/液氧作为推进燃料性能评价分析

为深入论证致密化低温推进剂带来的收益,系统性地分析了致密化液甲烷/液氧作为推进燃料的综合性能.构建了推进剂贮箱漏热、温升、增压压力、壁厚的动态热力模型,针对不同尺寸的液甲烷/液氧贮箱组合,分析了致密化液甲烷/液氧对燃料停放温升、发动机推力提升、贮箱增压压力降低、贮箱质量减轻的影响.并提出了致密化液甲烷/液氧过冷程度匹配...     

低温容器的隔热结构设计

对低温冷却器、低温循环器等设备中低温容器的隔热,用热阻分析的方法对隔热结构外壳不出现凝露的温度条件进行分析,导出了隔热结构最小热阻和限定单位漏热量时热阻的计算式、隔热材料的厚度设计方法。     

Layered composite thermal insulation system for nonvacuum cryogenic applications

A problem common to both space launch applications and cryogenic propulsion test facilities is providing suitable thermal insulation for complex cryogenic piping, tanks, and components that cannot be vacuum-jacketed or otherwise be broad-area-covered. To meet such requirements and provide a practical solution to the problem, a layered composite insulation system has been developed for nonvacuum applications and extreme environmental exposure conditions. Layered composite insulation system for extreme conditions (or LCX) is particularly suited for complex piping or tank systems that are difficult or practically impossible to insulate by conventional means. Consisting of several functional layers, the aerogel blanket-based system can be tailored to specific thermal and mechanical performance requirements. The operational principle of the system is layer-pairs working in combination. Each layer pair is comprised of a primary insulation layer and a compressible radiant barrier layer. Vacuum-jacketed piping systems, whether part of the ground equipment or the flight vehicle, typically include numerous terminations, disconnects, umbilical connections, or branches that must be insulated by nonvacuum means. Broad-area insulation systems, such as spray foam or rigid foam panels, are often the lightweight materials of choice for vehicle tanks, but the plumbing elements, feedthroughs, appurtenances, and structural supports all create “hot spot” areas that are not readily insulated by similar means. Finally, the design layouts of valve control skids used for launch pads and test stands can be nearly impossible to insulate because of their complexity and high density of components and instrumentation. Primary requirements for such nonvacuum thermal insulation systems include the combination of harsh conditions, including full weather exposure, vibration, and structural loads. Further requirements include reliability and the right level of system breathability for thermal cycling. The LCX system is suitable for temperatures from approximately 4 K to 400 K and can be designed to insulate liquid hydrogen, liquid nitrogen, liquid oxygen, or liquid methane equipment. Laboratory test data for thermal and mechanical performance are presented. Field demonstration cases and examples in operational cryogenic systems are also given.     

Spray-on foam insulations for launch vehicle cryogenic tanks

Spray-on foam insulation (SOFI) has been developed for use on the cryogenic tanks of space launch vehicles beginning in the 1960s with the Apollo program. The use of SOFI was further developed for the Space Shuttle program. The External Tank (ET) of the Space Shuttle, consisting of a forward liquid oxygen tank in line with an aft liquid hydrogen tank, requires thermal insulation over its outer surface to prevent ice formation and avoid in-flight damage to the ceramic tile thermal protection system on the adjacent Orbiter. The insulation also provides system control and stability throughout the lengthy process of cooldown, loading, and replenishing the tank. There are two main types of SOFI used on the ET: acreage (with the rind) and closeout (machined surface). The thermal performance of the seemingly simple SOFI system is a complex array of many variables starting with the large temperature difference of 200–260 K through the typical 25-mm thickness. Environmental factors include air temperature and humidity, wind speed, solar exposure, and aging or weathering history. Additional factors include manufacturing details, launch processing operations, and number of cryogenic thermal cycles. The study of the cryogenic thermal performance of SOFI under large temperature differentials is the subject of this article. The amount of moisture taken into the foam during the cold soak phase, termed Cryogenic Moisture Uptake, must also be considered. The heat leakage rates through these foams were measured under representative conditions using laboratory standard liquid nitrogen boiloff apparatus. Test articles included baseline, aged, and weathered specimens. Testing was performed over the entire pressure range from high vacuum to ambient pressure. Values for apparent thermal conductivity and heat flux were calculated and compared with prior data. As the prior data of record was obtained for small temperature differentials on non-weathered foams, analysis of the different methods is provided. Recent advancements and applications of SOFI systems on future launch vehicles and spacecraft are also addressed.     

高真空多层绝热低温液体运输半挂车的开发研制

简述高真空多层绝热低温液体运输半挂车的基本结构、绝热特性 ,并阐述了该车在低温液体运输的应用前景。     

绝热材料放气速率测试台研制

高真空条件下,绝热材料的放气速率会影响低温容器的真空性能,从而影响其绝热性能。根据GB/T31480-2015,搭建了绝热材料放气速率测试平台。通过本底放气速率的测定,验证了该测试平台的可靠性;利用静态法测试了某型号多层绝热材料的放气速率,给出了试验数据。本试验台将为绝热材料的应用及低温容器的设计提供数据支撑。     

Study on the Principle Mechanisms of Heat Transfer for Cryogenic Insulations: Especially Accounting for the Temperature-Dependent Deposition–Evacuation of the Filling Gas (Self-Evacuating Systems)

This study concentrates on the principles of heat transfer within cryogenic insulation systems, especially accounting for self-evacuating systems (deposition–evacuation of the filling gas). These principles allow the extrapolation to other temperatures, gases and other materials with the input of only a few experimentally derived or carefully estimated material properties. The type of gas (e.g. air or \(\hbox {CO}_{2}\)) within the porous insulation material dominates the behaviour of the effective thermal conductivity during the cooldown of the cryogenic application. This is due to the specific temperature-dependent saturation gas pressure which determines the contribution of the gas conductivity. The selected material classes include powders, fibrous insulations, foams, aerogels and multilayer insulations in the temperature range of 20 K to 300 K. Novel within this study is an analytical function for the total and the mean thermal conductivity with respect to the temperature, type of gas, external pressure and material class of the insulation. Furthermore, the integral mean value of the thermal conductivity, the so-called mean thermal conductivity, is calculated for a mechanically evacuated insulation material and an insulation material evacuated by deposition–evacuation of the filling gas, respectively. This enables a comparison of the total thermal conductivity of cryogenic insulation materials and their applicability for a self-evacuating cryogenic insulation system.     

无引线温度测量模块设计

针对温度场测量中使用常规温度传感器引线不方便的缺点,设计了一套无引线温度测量模块。该模块具有测量精度高、无需引线、使用方便的特点。测量模块配接热电阻传感器,利用参考电阻比例测量技术,大大提高了测量稳定性。测量模块采用真空隔热蓄热技术,在-65~200℃温度范围内正常工作不少于2 h,可满足该温区真空试验罐、热压罐,或其他密闭试验装置、大空间实验装置等温度场均匀性测量的需求。     

我国大型低温液体贮槽发展简况

近年来,随着现代化工业与科学技术的飞速发展,大型低温液体贮槽也得到相应的发展。我国先后设计并生产了容积３００ｍ＾３、４００ｍ＾３、５００ｍ＾３、１０００ｍ＾３的双层壳平底拱形顶常压粉末绝热的低温液体贮槽。文中简要介绍贮槽的结构特点、底部绝热、制造安装及相关的一些问题。     

有效导热系数对低温容器日蒸发率的影响

低温容器是气体液化分离加工工业中的重要设备，绝热设计是低温容器设计的重要组成部分，它直接影响低温容器的日蒸发率。在不同的绝热材料和一定漏热温差的条件下，给出了普通绝热和真空粉末绝热型低温容器的日蒸发率与热材料的有效导热系数以及绝热层厚度之间的关系曲线。为简化设计和比较低温容器的特性提供方法和依据。     

阻燃型低温绝热纸的出气速率和出气成分测试

低温绝热纸是制造多层绝热低温容器的重要材料之一。在真空条件下绝热纸的出气速率影响低温容器的真空性能,是低温容器设计的重要依据。介绍了低温绝热纸测试装置的设计及技术指标,利用静态法测试了阻燃型低温绝热纸的出气速率和出气成分,给出了试验数据。     

Experimental study on cryogenic moisture uptake in polyurethane foam insulation material

Rigid foam is widely used to insulate cryogenic tanks, in particular for space launch vehicles due to its lightweight, mechanical strength and thermal-insulating performance. Up to now, little information is available on the intrusion of moisture into the material under cryogenic conditions, which will bring substantial additional weight for the space vehicles at lift-off. A cryogenic moisture uptake apparatus has been designed and fabricated to measure the amount of water uptake into the polyurethane foam. One side of the specimen is exposed to an environment with high humidity and ambient temperature, while the other with cryogenic temperature at approximately 78 K. A total of 16 specimens were tested for up to 24 h to explore the effects of the surface thermal protection layer, the foam thickness, exposed time, the butt joints, and the material density on water uptake of the foam. The results are constructive for the applications of the foam to the cryogenic insulation system in space launch vehicles.