细长船对中深水底引起的动水压力系数计算

文献对水压场的基本方程进行分析,得出了水压场的“浅水理论”。本文用它对中深水细长船水压场某些方面进行分析,即用它对中深水细长船水压场进行计算(船的正下方除外)和对不同水底深度的动水压力系数进行换算。两者所得结果在亚临界流动范围内均较为满意。     

极压抗磨性能良好的润滑油添加剂

本文对含硫、钼的有机化合物的合成及性能进行了研究,并探讨了其化学结构对极压抗磨性能的影响。四球机试验表明:这类化合物有很好的抗磨性能和较高的承载能力,在润滑油中性能稳定,是较好的极压抗磨添加剂。烃基的改变对其极压抗磨性能有一定的影响。     

Experimental study on the cavity evolution and liquid spurt of hydrodynamic ram

In research of the characteristics of the cavity evolution, the pressure, and the liquid spurt in hydrodynamic ram, the experiment of the high-velocity fragment impacting the water-filled container had been conducted. The relationships between the above three characteristics have been researched. The evolution of the cavity can be divided into three processes according to its shape characteristics. The first liquid spurt occurred in Process Ⅱ and the rest of it occurred in Process Ⅲ. The duration of the second liquid spurt is longer than the first liquid spurt. When the impact velocity of the fragment is less than 996 m/s, the velocity of the second liquid spurt is the highest. When the velocity of the fragment is greater than 996 m/s, the velocity of the first liquid spurt is the highest. The maximum velocities of the first and second liquid spurt are 111 m/s and 94 m/s respectively. The pressure fluctuated sharply in Processes Ⅰ and Ⅲ. The maximum peak pressures in the shock and the cavity oscillation phases are 15.51 MPa and 7.96 MPa respectively. The time interval of the two adjacent pressure pulses increases with the increase of the fragment velocity.     

军用柴油机高压共轨系统共轨管设计与仿真

结合大功率柴油机配机要求,进行了高压共轨喷油系统共轨管结构设计研究。针对某型军用柴油机结构和共轨管结构特点,提出适合的柴油机高压共轨系统方案,确定了双轨结构型式的共轨管,计算了不同共轨管的结构参数。通过建立双共轨管的简化仿真模型,分析双轨结构不同参数的共轨管压力波动变化,提出了双共轨管参数方案,结果表明该方法能获得较合理的双共轨管参数。     

数据耕耘方法

数据耕耘是从美海军"艾伯特计划"中总结出的一种系统分析方法,它通过播种、施肥、耕作、栽培和收获等过程的循环,为探索问题提供了永无止境的机会.数据耕耘将蒸馏法作用于需求空间、能力空间、想定空间和结果空间,通过运行简单的模型,快速探索出较大的决策空间.该方法模型具有层次化变精度、动态有环反馈、数据可视化、基于 Agent运作综合等特性,目前主要应用于军事决策领域.     

发动机空载减速过程仿真与试验研究

以某型履带车辆发动机动力和传动系统为研究对象,应用CFD软件和虚拟样机软件对发动机空载减速过程进行仿真计算。模拟了不同漏气当量下该型发动机空载减速过程,并通过实车试验进行了验证,为基于空载减速过程的发动机技术状况评估提供了理论依据与试验方法。     

舰用主锅炉低负荷时升压运行对蒸汽净化的影响

分析了蒸汽压力变化对饱和蒸汽湿度和汽水分离的影响,并在模拟器上进行了定量计算,得出的结论为某型舰用主锅炉低负荷时升压运行提供了理论依据.     

The properties of Sn–Zn–Al–La fusible alloy for mitigation devices of solid propellant rocket motors

The Al and La elements are added to the Sn9Zn alloy to obtain the fusible alloy for the mitigation devices of solid propellant rocket motors. Differential scanning calorimetry (DSC), metallographic analysis, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), tensile testing and fracture analysis were used to study the effect of Al and La elements on the microstructure, melting characteristics, and mechanical properties of the Sn9Zn alloy. Whether the fusible diaphragm can effectively relieve pressure was investigated by the hydrostatic pressure at high-temperature test. Experimental results show that the melting point of the Sn9Zn-0.8Al0·2La and Sn9Zn–3Al0·2La fusible alloys can meet the predetermined working temperature of ventilation. The mechanical properties of those are more than 35% higher than that of the Sn9Zn alloy at −50 °C–70 °C, and the mechanical strength is reduced by 80% at 175 °C. It is proven by the hydrostatic pressure at high-temperature test that the fusible diaphragm can relieve pressure effectively and can be used for the design of the mitigation devices of solid propellant rocket motors.     

亚临界航速时双船水压场数值计算与实验研究

基于RANS方程,采用VOF方法,选用SST湍流模式,对两艘不同排水量Wigley船同向航行时的水压场进行了数值计算,并开展了双船水压场的实验研究,计算结果与实验结果吻合良好。研究表明:双船在浅水中航行时,由于两船及其引起的兴波相互作用,双船水压场负压峰值和负压延时等特征与两船相对位置密切相关,与单船水压场特征有明显区别。     

Response of masonry systems against blast loading

In this paper eight successive experimental blast tests with an increasing TNT equivalent charge weights ranging from 0.56 kg to 17.78 kg were conducted on unreinforced, ferrocemented overlay masonry and confined masonry walls. The pressure-time history caused by the blast was recorded by pressure sensors installed on the test specimen. The resulting damage pattern was observed during each test. Weak zones in the three systems of masonry were identified. Scaled distances for different damage levels in the three masonry systems were experimentally obtained. The results provide a basis for determining the response of each masonry system against blast loading. Consequently, efficiency of ferrocemented overlay ma-sonry and confined masonry was found established in mitigation against blast loads.