阀门低温试验节能性研究

阀门低温试验是检验低温阀门质量的一个重要手段,试验过程中需要消耗大量的试验冷媒和试验介质。针对阀门低温深冷试验装置,运用低温传热学原理,进行试验冷媒和试验介质消耗的定量分析,确定消耗公式,提出节能优化的解决方案。     

低温阀门深冷试验装置的设计

结合工程实际,提出了一种较完整的低温阀门深冷试验装置设计方案,并就装置结构、参数检测、深冷处理机理和低温试验方法等方面的内容进行了探讨.     

基于计算机数据采集的低温阀门性能测试装置

介绍了一种基于计算机数据采集的低温阀门性能测试装置,该装置具有对试验数据集中储存、显示和打印等功能,并可实现对液氮罐自增压系统的自动控制,可提高试验的工作效率、操作及时性、准确性和安全性。指出将计算机技术、光电技术等应用于试验装置上是今后的发展方向。     

基于计算机数据采集的低温阀门性能测试装置

介绍一种基于计算机数据采集的低温阀门性能测试装置,该装置具有对试验数据集中储存、显示和打印功能,并可实现对液氮罐自增压系统的自动控制,可提高试验的工作效率、操作及时性、准确性和安全性。指出将计算机技术和光电技术等应用于试验装置上是今后的发展方向。     

阀门低温试验装置

阐述了采用浸渍法的阀门低温试验装置在设计、制造中应注意的问题，并对低温试验作了简要介绍。     

降低低温截止阀波纹管破坏率的研究

低温截止阀门是运输液氢、液氧、液氮等低温介质时的关键设备,广泛应用于我国航天领域试车和发射任务中.波纹管是低温截止阀门中重要的组件,起到补偿低温介质引起的阀门管壁伸缩变形的作用.在低温阀门的制造、组装和试验的过程中,阀门波纹管的破坏率较高,使得阀门局部或整体结构失效,难以修复.论文通过对实际操作的调研和理论研究,从人员、设计、工艺、材料等方面分析了导致阀门波纹管破坏的原因,并基于这些破坏的原因制定了一系列避免波纹管损坏的方法,有效避免了在阀门的制造、组装和试验过程中波纹管的破坏,达到了降低阀门的生产成本、缩短阀门的生产周期,保证阀门的高可靠性的目的.     

低温阀门的设计与研制

介绍了低温阀门的结构设计；给出了低温阀门长颈阀盖设计公式；论述了３．５Ｎｉ低温铸钢的冶炼方法及低温阀门的试验方法以及低温试验介质的选择原则。     

DL-1低温拉伸试验装置的设计

介绍了一种专门用于低温拉伸试验的新型试验装置,对试验中使用的低温箱、制冷剂、材料试验机等进行了选择,并对装置中的关键部件—拉头以及低温引伸仪进行了设计计算。     

球阀的低温试验

低温试验是对低温阀门性能验证的一个重要手段,现行标准规定的阀门低温试验方法与实际工况有一定的差异,不当的操作容易造成试验结果的失真,甚至对受试阀门的损害。本文主要针对低温球阀的特殊结构,分析了阀门低温试验中容易出现的问题,并结合实际操作经验,提出了一些应对措施。     

液化天然气用超低温阀门的设计与研究

介绍了液化天然气装置用超低温阀门的工况特性、结构设计、制造工艺及其材料的选择与处理方法。分析了超低温阀门的密封结构、关闭力矩及相关零件的材料性能。给出了超低温阀门的低温密封试验装置系统和试验的步骤与结果。     

Flow instability due to cryogenic cavitation in the downstream of orifice

Flow instability in LRE (liquid rocket engine) occurs due to various reasons such as flow interactions with valve, orifice and venturi, etc. The inception of cavitation, especially in the propellant feeding system, is the primary cause of mass and pressure oscillations because of the cyclic formation and depletion of cavitation. Meanwhile, the main propellant in a liquid rocket engine is the cryogenic fluid, which properties are very sensitive to temperature variation. And the change of propellant properties to temperature variation by thermodynamic effect needs to be properly taken into account in the flow analysis in order to understand basic mechanisms for cryogenic cavitation. The present study focuses on the formation of cryogenic cavitation by using the IDM model suggested by Shyy and coworkers. The flow instability was also numerically investigated in the downstream of orifice with a developed numerical code. Calculation results show that cryogenic cavitation can be a primary source of flow instability, leading to mass fluctuations accompanied by pressure oscillations. The prediction of cavitation in cryogenic fluid is of vital importance in designing a feeding system of an LRE. This paper was recommended for publication in revised form by Associate Editor Jun Sang Park Changjin Lee received his B.S. and M.S. degrees in Aeronautical Engineering from Seoul National University in 1983 and 1985. He then went on to receive his Ph.D. degree from University of Illinois at Urbana- Champaign in 1992. Dr. Lee is currently a Professor at the department of Aerospace Engineering at Konkuk University in SEOUL, Korea. His research interests are in the area of combustion instabilities of hybrid, liquid rocket and jet propulsions. Tae-Seong Roh received his B.S. and M.S. degrees in Aeronautical Engineering from Seoul National University in 1984 and 1986. He then went on to receive his Ph.D. degree from Pennsylvania State University in 1995. Dr. Roh is currently a Professor at the department of Aerospace Engineering at Inha University in Incheon, Korea. His research interests are in the area of combustion instabilities, rocket and jet propulsions, interior ballistics, and gas turbine engine defect diagnostics.     

低温低噪声放大器噪声测试系统

在低噪声放大器噪声线性的基础上，介绍了负载温度可变法，用于测量低温低噪声放大器的噪声。建立一套低温放大器噪声测试系统，并分析了系统的测量误差。利用系统测量了S波段和C波段低温放大器各1个，测试结果与国外同类测试系统的测试结果相符。系统的建立为我国自主研发低温低噪声放大器提供了必要条件。     

Cryogenic tilt table

We describe the design and development of a cryogenic tilt table that will be used to test the flight hardware for NASA’s Satellite Test of the Equivalence Principle (STEP). Our table can tilt the hardware around two axes and is part of a test bed that has 6-degree-of-freedom controllability. The goal was to build a tilt table with a resolution better than ∼5 μrad (1 arcsec). Our table consists of three aluminum plates. The outermost plate is attached to the cryogenic probe and is fixed. The middle and inner plates rest on the outer and middle plates, respectively, using knife edges and knife edge holders made of silicon nitride that are glued to the aluminum plates. A cryogenic tilt sensor was also developed and integrated with the table. The sensor consists of an electrically grounded copper cube hanging from a support, and is placed between two pairs of capacitive electrodes. Any motion of the cube caused by tilting is measured differentially using a Wheatstone bridge circuit. The table is connected to the bottom of a cryogenic probe. A voice coil actuator, located on top of the probe at room temperature, is used to create the necessary tilt. A thin fiber is used to connect the actuator and the table. The system is controlled using a dSPACE control card. A test of the table at cryogenic temperatures (4.5 K) and low pressure (1 μTorr) showed a noise level of ∼0.7 μrad (150 marcsec), which is nearly an order of magnitude better than the required resolution.     

Lubrication effect of liquid nitrogen in cryogenic machining friction on the tool-chip interface

The liquid nitrogen as an environmentally safe coolant has been widely recognized in cryogenic machining, its function as a lubricant is plausible due to its chemical inertness, physical volatility and low viscosity. Since a reduced friction is a direct witness of the lubrication effect from a tribological viewpoint, this paper presents an evaluation of the apparent friction coefficient on the tool-chip interface in cryogenic cutting operations to prove and characterize the lubricity of LN2 in cryogenic machining. The cryogenic cutting technology used in this study is based on a cooling approach and liquid nitrogen delivery system which are intended to apply liquid nitrogen in well-controlled fine jets to selectively localized cutting zones and to penetrate liquid nitrogen to the tool-chip interface. It has been found that the apparent friction coefficient can be significantly reduced in cryogenic machining, depending on the approach of liquid nitrogen delivery.     

CP—4010型低温吹扫捕集装置及其在环境样品测定中的应用

系统地介绍了CP－4010型低温吹扫捕集装置的结构和原理,并结合实际,介绍了低温吹扫捕集装置在环境样品分析中的应用。     

深冷处理的铝合金点焊电极寿命研究

为了提高铝合金点焊电极寿命,提出了点焊电极的深冷处理方法。采用不同深冷处理工艺参数加工了点焊电极,用这些电极进行了铝合金点焊电极寿命试验,比较了深冷处理电极与未深冷处理电极寿命,观测、比较了深冷处理前后点焊电极端面、焊点表面的宏观形貌,观察了深冷处理电极与未深冷处理电极微观组织,测试了深冷处理电极与未深冷处理电极物理性能。试验结果表明:深冷处理改变了电极微观组织,改善了电极导电、导热性能,提高了点焊电极寿命,使电极寿命由原来的620点提高到2 145点。     

LNG接收站低温控制阀的选型设计

低温控制阀是LNG接收站操作控制中的主要执行单元,控制阀的正确选型是保证阀门正常运行及工艺操作的关键环节。该文具体分析了LNG接收站低温控制阀的选型设计要点,包括阀门类型、材料选择、特殊设计、口径选择、执行机构、低温试验等。