燃气轮机仿真软件构造方法综述

从方法论的角度综述了燃气轮机仿真软件的研究现状,分析了过程式方法和过程式模块化方法的不足,阐明采用面向对象方法的必要性,并对未来的发展方向作了初步探讨.     

On the continued acceleration of bomb casing fragments following casing fracture

It has been said that, once a bomb casing has fractured, “detonation gases will then stream around the fragments or bypass them, and the acceleration process stops there.” However, while apparently copious gas flow through casing fractures indicates some pressure release, it is also an indication of significant gas drive pressure, post casing fracture. This paper shows two approaches to the problem of calculating the actual loss of drive. One presents first-order analytical calculations, in cylindrical geometry, of pressure loss to the inside surface of a fractured casing. The second shows the modelling of a selected example in the CTH code. Both approaches reveal that gas escape, while occurring at its own sound-speed relative to the adjacent casing fragments, has to compete with rapid radial expansion of the casing. Together with some historic experiments now publicly available, our calculations indicate that post-fracture casing fragment acceleration is, for most systems, unlikely to be reduced significantly.     

Effect of fusion welding processes on tensile properties of armor grade,high thickness,non-heat treatable aluminium alloy joints

AA5059 is one of the high strength armor grade aluminium alloy that finds its applications in the military vehicles due to the higher resistance against the armor piercing (AP) threats. This study aimed at finding the best suitable process among the fusion welding processes such as gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) by evaluating the tensile properties of AA5059 aluminium alloy joints. The fracture path was identified by mapping the low hardness distribution profile (LHDP) across the weld cross section under tensile loading. Optical and scanning electron microscopies were used to characterize the microstructural features of the welded joints at various zones. It is evident from the results that GTAW joints showed superior tensile properties compared to GMAW joints and this is primarily owing to the presence of finer grains in the weld metal zone (WMZ) and narrow heat-affected zone (HAZ). The lower heat input associated with the GTAW process effectively reduced the size of the WMZ and HAZ compared to GMAW process. Lower heat input of GTAW process results in faster cooling rate which hinders the grain growth and reduces the evaporation of magnesium in weld metal compared to GMAW joints. The fracture surface of GTAW joint consists of more dimples than GMAW joints which is an indication that the GTAW joint possess improved ductility than GMAW joint.     

轨、姿控固体燃气发生器式动力系统研究

概述了固体燃气发生器的特点及发展状况,提出了如何进一步研究的建议。     

混合气体识别的响应等效性与瞬态信号正交分解模型

针对目前混合气体识别大多采用传感器稳态响应信号、基于线性混合假设或大量样本学习,而瞬态响应信号特征分析主要应用非正交分解的问题,提出一种基于响应等效性与瞬态信号正交分解的混合气体识别模型。分析金属氧化物半导体传感器对混合气体的响应特性,建立基于气体响应成分等效性假设的气体非线性混合模型,在此基础上,提出并应用一种新的正交基函数——扩展类Legendre正交基,对气体传感器瞬态响应信号进行分解;通过对正交分解系数与气体浓度的回归分析,验证二者之间的指数型关联关系,并以正交分解系数为特征参数,利用气体非线性等效混合模型对混合气体分解与辨识。实验结果表明,尽管这种混合气体识别模型仅用单一气体检测的先验知识,对混合气体的识别误差仍可达到15%以内。     

考虑入口和出口容积效应的涡轮动力学模型

建立了考虑涡轮入口和出口容积效应的涡轮动力学模型 ,利用该模型计算了燃气涡轮气瓶启动的动态响应过程 ,分析了影响涡轮动态特性的主要因素。计算结果表明 :涡轮前容积对涡轮入口压力和出口背压的过渡过程均有显著的影响 ,涡轮后容积对涡轮入口压力的过渡过程影响不大 ,对涡轮出口背压的影响显著。     

煤气泄漏报警原理用于潜艇消氢系统的自动控制设计

作者设计了一种煤气泄漏报警装置,并把它的工作原理移植到潜艇消氢系统的设计中,将原来用于手工检测、分散消氢的消氢过程改造成自动检测、集中消氢的自动控制过程,达到了减轻艇员劳动强度,大大提高测氢与消氢的及时性与准确性的目的。实艇的初步试验表明,系统设计是成功的,存在的某些问题需要依靠潜艇修理时才能解决。     

不可逆闭式燃气轮机循环的最佳功率效率特性

本文研究恒温热源条件下不可逆闭式燃气轮机循环的有限时间热力学性能,导出其最佳功率输出与效率间的关系,它包含内可逆和理想换热条件下的最佳特性关系。     

间歇法制合成氨原料气的分析

系统地分析了中型合成氨厂以焦炭为原料制取合成氨原料气的有效能损失与分布情况。从热力学角度剖析了节能的潜力,为工艺改造指出了方向。     

舰用燃气轮机起动失效分析

以舰用燃气轮机为对象,在简述燃气轮机起动过程的基础上,分析其起动失效的各种原因,提出解决的方法,为燃气轮机的操作及维护提供参考．