低温液体火箭发动机循环预冷模拟试验

进行了低温液体火箭发动机自然循环预冷过程的模拟实验,试验证明了回流管进入储箱液面之上和进入液面之下的两种方案均可实现自然循环预冷,但是要维持自然循环继续进行,前者必须增加引射,而后者不需引射。模拟试验结果可供进一步试验研究参考。     

大推力氢氧火箭发动机试验噪声治理技术概述

在大推力氢氧火箭发动机试验中,噪声问题越来越突出,有必要对其采取噪声治理措施。总结大推力氢氧火箭发动机噪声治理的难点和影响大推力氢氧火箭发动机噪声治理的因素,介绍大推力氢氧火箭发动机高空模拟试验和地面试验的降噪方法,并对喷水降噪后进一步的噪声治理措施给出建议。     

低温推进剂输送系统循环预冷非稳态数值模拟研究

针对某带引射装置的循环预冷系统,基于一维非平衡两流体模型,结合引射器模型建立采用交错网格与两步求解法,数值模拟并分析了整个自然循环(含引射增强)预冷非稳态进程,定量评价了循环流动特性、引射增强及预冷效果.数值模拟并探讨了循环预冷系统参数对预冷状态与过程的影响.     

氦气/液氧喷射泵水调试验

在水调试验台上对自行设计的氦气/液氧喷射泵进行了试验研究.研究结果表明,在其它条件相同的情况下,随着氦气耗量增加,液氧流量呈先增加后减小趋势,其最大值对应的氦气压力比为1.62-2.95,引射效率约100-160.实践表明,水调试验结果与预冷循环系统调试结果基本一致,为预冷循环系统喷射泵设计提供了高可靠的模拟环境.     

共底贮箱氢氧泄漏监测设备研制

本文介绍了共底贮箱氢氧泄漏监测设备的详细结构设计，包括共底抽真空装置、共底气体成分分析装置、发射现场抽空管路和现场使用流程优化等内容。目前，所研制的2套共底氢氧泄漏监测设备已顺利交付使用，并已参与了3次发射任务，确保了火箭发射任务期间的航天器安全和发射人员人身安全，未来将持续服务于新一代中型运载火箭高密度发射任务。     

管路流体对氢氧发动机推力测量的影响分析

为了进一步量化管路流动特性对氢氧火箭发动机推力测量的影响,通过对试验系统低温调试进行推力校准,主要采用常温常压和低温增压两种方式确定校准过程结果,结合误差分析理论计算出管路流体对推力测量引入的误差,同时得出推力测量结果的修正值,并与发动机试验点火前数据进行比对分析,确定两者的一致性.     

基于时间序列模型的荔枝预冷过程果肉温度变化特性

目的 解决荔枝在采后预冷过程中预冷时间难把握、预冷后处理时间长导致的果肉温度偏高等问题。方法 通过研究不同环境下荔枝果肉温度变化与时间的关系，设计荔枝果肉的温降和温升试验，模拟荔枝预冷和晾干包装阶段的温度变化过程，提出一种时间序列下的荔枝果肉温度预测模型。结果 基于时间序列模型的荔枝果肉温度变化预测值与试验值具有高度的一致性，均方差均在80%以上，表明预测结果稳定、可靠。在2～3℃冰水预冷环境下，荔枝果肉从26℃降至5℃约需14 min，将预冷后在室温（25℃）下晾干的处理时间控制在4～6 min内，可以有效地减少荔枝入库贮藏前果肉温度过高的问题，提高了荔枝的冰水预冷效果，保证荔枝在贮藏期间具有较佳的品质。结论 通过构建时间序列模型，研究荔枝预冷过程中果肉的温度变化特性，可为荔枝在预冷、晾干、包装环节的过程参数控制提供参考依据。     

低温推进剂火箭发动机循环预冷系统喷泉非稳现象的数值研究

通过数值模拟,分析了低温推进剂(液氧)火箭发动机循环预冷系统中喷泉非稳现象的过程与机理;计算分析了不同影响因素下的喷泉现象及行为规律;同时,参照针对竖直立管的喷泉失稳边界Murphy曲线,对比探讨了输送管几何与保温参数影响下的自然循环预冷回路的喷泉稳定性边界;进一步地,针对特定循环预冷回路,数值分析并验证了消除喷泉效应的有效措施.     

提高多管火箭射击密集度设计技术研究

为了提高多管火箭的射击密集度,利用多体系统传递矩阵法建立了某多管火箭发射动力学模型和射击密集度仿真系统,用多管火箭固有振动特性的模态试验结果验证了相关仿真结果,利用仿真系统对不同发射环境下振动特性、动力响应和密集度进行仿真研究,并对射序和射击间隔对密集度的影响进行仿真研究,得到提高多管火箭密集度发射的最佳射序和射击间隔,研发了小型化的多管火箭可变射序和射击间隔发火装置,可实现最佳射序和射击间隔高密集度发射,在某次密集度试验中,利用该发射技术使某多管火箭射击密集度提高20％以上.     

氮水预冷系统冷却水循环路线的改进

<正>我厂根据生产规模不断扩大的需要,于1991年年底购买原总后2672-1-厂闲置的1974年杭氧厂产的1000m~3/h空分设备,1992年12月2日联动试车,一次成功,氧产量达1123m~3/h。但裸冷试车过程中,发现原来氮水预冷系统工况达不到空气进塔工况的要求,因此我们对氮水预冷系统进行了改造。     

Metallurgical Investigation of Cracked Adaptor Welded to Cryogenic Dump Coolant Line of Engine Test Stand

In the upper stages of satellite launch vehicles, a cryogenic propulsion system is used because of its high specific impulse. Such stages were tested for qualification using ground hot test facility. During one of the hot tests, the stainless steel adaptor welded to the engine dump coolant line, and used for accommodating temperature sensors, broke away from the tube. The detailed metallurgical investigation was carried out, and the reason for cracking was attributed to improper welding. This article highlights the details of investigation carried out.     

液氧煤油火箭发动机排放预冷数值仿真

针对预冷过程中输送系统和发动机流道内沸腾传热和两相流动过程,建立一维二流体模型。以某液氧煤油发动机为原型,对不同气枕压力、排放管径和空中排放时间条件下排放预冷过程进行仿真,分析进出口温度以及流量特性的变化情况,结果表明增大排放管径和排放压力均可以增强预冷效果,而空中排放预冷时达到同样预冷效果所需的推进剂量则与管径大小无关,并且预冷效果受到地面状态的影响。     

Metallurgical investigation of cracked stainless steel plumbing tubes used in engine gimbal control system of satellite launch vehicle

The attitude control of satellite launch vehicle employs various control modules. Gimbling the engine nozzle within a specified angle through actuator modules is commonly used to control the deviation in predetermined trajectory path of satellite launch vehicles. During one of the hot test of a liquid engine stage, a drop in pressure in actuator module was noticed due to cracking of plumbing line. This called for disabling the gimbal control during the test.Subsequently to the test, while opening the leaked joint, a through circumferential crack was seen at the neck of the flared tube. Detailed metallurgical investigation revealed that the failure was due to fatigue. This paper brings out the detail of investigation carried out and conclusion arrived on.     

Optimization of the process of plasma ignition of coal

Results are given of experimental and theoretical investigations of plasma ignition of coal as a result of its thermochemical preparation in application to the processes of firing up a boiler and stabilizing the flame combustion. The experimental test bed with a commercial-scale burner is used for determining the conditions of plasma ignition of low-reactivity high-ash anthracite depending on the concentration of coal in the air mixture and velocity of the latter. The calculations produce an equation (important from the standpoint of practical applications) for determining the energy expenditure for plasma ignition of coal depending on the basic process parameters. The tests reveal the difficulties arising in firing up a boiler with direct delivery of pulverized coal from the mill to furnace. A scheme is suggested, which enables one to reduce the energy expenditure for ignition of coal and improve the reliability of the process of firing up such a boiler. Results are given of calculation of plasma thermochemical preparation of coal under conditions of lower concentration of oxygen in the air mixture.     

汽车排气消声器的降噪优化设计

以控制汽车加速噪声为背景，通过对某微型卡车排气消声器的测试分析结果，提出相应的改进措施。在利用数值模拟优化的基础上，完善改进方案。台架试验证明改进后的消声器插入损失增加7.1dB（A），而背压没有明显变化。整车加速噪声试验证明改进后的消声器可以使整车加速噪声降低2dB（A），降噪效果显著。     

低温推进剂贮箱增压过程的传热传质数学模拟

针对火箭发动机地面试验中低温液氧贮箱的预增压和增压过程建立了气相空间的传热、传质数学模型.运用实际气体的状态方程、连续性方程、能量守恒方程以及推进剂与气相空间的传热、传质方程等组成了关于气相空间参数的微分方程组,并运用四阶Runge-Kutta算法对其进行求解.获得了气相空间的压力、温度、增压气体流量、液氧挥发速率以及贮箱壁温等参数的变化规律.结果表明,在发动机启动前的预增压过程中,气相空间的温度和压力急剧增加,液氧的挥发速率也增加很快;发动机启动后的保持增压阶段,由于气相空间的体积不断发生变化,气相空间参数的变化趋于平缓,液氧表面向气相空间的传质速率也趋于稳定.     

弹性支撑模型对火箭发射过程结构振动响应影响研究EI北大核心CSCD

固体火箭从发射筒发射过程中,采用弹性支撑降低火箭结构与发射筒内壁接触引起的冲击,弹性支撑力学模型对火箭发射过程中结构振动响应计算存在影响。利用多体动力学建立包含火箭、发射筒、弹性支撑在内的发射动力学模型,在火箭发射物理过程分析基础上,利用ANSYS/LS-DYNA软件建立火箭壳体与弹性支撑局部有限元模型,获得了火箭壳体与弹性支撑接触面积变化对支撑刚度影响规律,在此基础上,提出了用于火箭发射多体动力学建模的弹性支撑改进模型,求解弹性支撑模型改进前后火箭发射过程结构振动响应与弹性支撑支反力,分析了弹性支撑模型改进对结构振动响应的影响及其原因。结果表明:提出的弹性支撑改进模型可以准确描述火箭尾部结构脱离弹性支撑过程中接触面积逐渐变化到零的物理过程;与弹性支撑模型改进前相比,改进后结构弯矩响应峰值显著减小。该成果有助于准确评估火箭发射过程结构响应水平,对于火箭结构精细化设计具有工程意义。     

Aquacells — Flagellates under long-term microgravity and potential usage for life support systems

The motile behavior of the unicellular photosynthetic flagellate Euglena gracilis was studied during a two-week mission on the Russian satellite Foton M2. The precision of gravitactic orientation was high before launch and, as expected, the cells were unoriented during microgravity. While after previous short-term TEXUS flights the precision of orientation was as high as before launch, it took several hours for the organisms to regain their gravitaxis. Also the percentage of motile cells and the swimming velocity of the remaining motile cells were considerably lower than in the ground control. In preparatory experiments the flagellate Euglena was shown to produce considerable amounts of photosynthetically generated oxygen. In a coupling experiment in a prototype for a planned space mission on Foton M3, the photosynthetic producers were shown to supply sufficient amounts of oxygen to a fish compartment with 35 larval cichlids, Oreochromis mossambicus.     

机载多管火箭非满管射击试验方法研究

研究机载多管火箭非满管射击试验方法,为减少机载多管火箭密集度试验用弹量提供新的试验方法。应用发射动力学和多体系统传递矩阵法理论,基于等起始扰动思想,建立了机载多管火箭发射动力学模型、特征方程和动力响应方程,并应用随机整数规划方法,形成了减少机载多管火箭试验用弹量方法。针对某19管机载多管火箭,提出了6发连射的密集度试验方案,试验验证使密集度试验用弹量比常规试验方法减少了68.4%,节省了大量试验费用。     

Experience with platinum aluminide coatings in land-based gas turbines

Hot-corrosion crucible tests with salt mixtures which simulated actual blade deposits were carried out to evaluate the potential of platinum-modified aluminide coatings for application in advanced industrial gas turbines. In comparison with simple aluminide coatings, a significantly improved resistance against hot corrosion at intermediate temperatures was found. At the highest turbine-operating temperature, coating life exceeds that of conventional plasma-sprayed NiCrSi coatings. Actual engine test results are presented which confirm the beneficial role of platinum. However, the susceptibility of platinum aluminide coatings to crack formation and propagation may make them unsuitable for application to rotating blades.