战斗机阻力伞载荷计算研究

目的通过对战斗机阻力伞载荷计算开展研究,为阻力伞安装支持结构的静强度和疲劳强度分析提供支持。方法分别运用工程计算方法、流固耦合数值模拟方法,并对比阻力伞火箭滑车试验实测数据,对阻力伞载荷计算开展研究。同时基于飞参数据,运用统计学方法对影响阻力伞载荷大小和方向的开伞速度、飞机俯仰角、侧风速度与方向等参数进行统计分析,为载荷谱编制提供数据基础。结果确定阻力伞载荷工程计算方法中动载系数k取为1.2,将一次放伞的载荷历程简化为以拉直力和张满力为峰值的两个载荷循环,且拉直力为张满力的50%。以某型飞机766架起落飞参数据为基础,运用皮尔逊Ⅲ型分布、指数分布对开伞速度、飞机俯仰角、侧风速度与方向等参数进行拟合,结合阻力伞载荷计算方法,得出阻力伞载荷大小和方向分布的统计规律。结论明确了阻力伞载荷计算方法及计算相关参数选取,同时提出一种符合战斗机实际使用环境的阻力伞载荷谱编制方法。     

Experimental and numerical analysis of a helical coil solar cavity receiver: Thermal oil as the heat transfer fluid

The paper presents the novel design of double glazing helical coil solar cavity receiver for solar thermal applications. Performance model has been developed for the experimental setup based on energy balance equations. The results obtained were compared with horizontal tube receiver for the same experimental setup. The result shows that the 87.96% improvement in the convective heat transfer coefficient for the double glazing helical coil solar cavity receiver. Maximum conversion efficiency achieved is 21% more than that would be obtained for horizontal tube receiver. This paper also investigates how the quality of vacuum degraded with the temperature of the glass cover.     

高校安全管理模型建立及对策研究

高校的安全问题日益突出,严重威胁师生的人身和财产安全,影响校园的和谐稳定。如何减少校园事故的发生,提高安全管理效率,是目前研究的热点。本文根据高校事故发生的"5M原理",揭示导致校园事故发生的多种因素,结合AHP理清了各因素之间的复杂层次关系,建立5个一级指标、30个二级指标的高校评价指标体系。根据L高校实际情况,制定了危险控制的基本措施,依据构建的基于"新木桶理论"安全管理模型,为高校安全事故的预防提供借鉴。     

超临界流体萃取与超临界水裂解耦合处理油泥中试

传统油泥处理存在能耗高、易造成二次污染、资源利用率低等问题。采用多级超临界流体萃取-超临界水裂解耦合技术对经减量化处理的油泥进行无害化处理及资源化利用,其中通过多级超临界流体梯度萃取可生成重质油、高级酚及稠环芳烃,在催化剂作用下超临界水将油泥中残留的重胶质及沥青质裂解为CO、H_2、丙烯、丁烯等组分,处理后的油泥石油烃综合利用率高,残渣可实现无害化排放。     

压裂返排液循环使用技术综述

综述了传统处理方法和深度处理方法两大类压裂返排液处理方法的特点和处理效率。介绍了对氧化破胶的压裂返排液和非氧化破胶的压裂返排液进行处理的方法和机理,以及返排液循环使用效果和性能检测的标准。指出研发含有高分子聚合物稠化剂的返排液循环使用工艺、高效便捷的压裂返排液循环使用工艺和新型可循环使用的压裂液体系等将是未来压裂返排液循环使用的发展方向。     

Investigation of activated carbon/ethanol for low temperature adsorption cooling

Commercially available adsorption cooling systems use water/silica gel, water/zeolite and ammonia/ chloride salts working pairs. The water-based pairs are limited to work above 0°C due to the water high freezing temperature, while ammonia has the disadvantage of being toxic. Ethanol is a promising refrigerant due to its low freezing point (161 K), nontoxicity, zero ozone depletion, and low global warming potential. Activated carbon (AC) is a porous material with high degree of porosity (500–3000 m²/g) that has been used in wide range of applications. Using Dynamic Vapour Sorption (DVS) test facility, this work characterizes the ethanol adsorption of eleven commercially available activated carbon materials for cooling at low temperature of ?15°C. DVS adsorption results show that Maxsorb has the best performance in terms of ethanol uptake and adsorption kinetics compared to the other tested materials. The Maxsorb/ethanol adsorption process has been numerically modeled using computational fluid dynamics (CFD) and simulation results are validated using the DVS experimental measurements. The validated CFD simulation of the adsorption process is used to predict the effects of adsorbent layer thickness and packing density on cycle uptake for evaporating temperature of ?15°C. Simulation results show that as the thickness of the Maxsorb adsorbent layer increases, its uptake decreases. As for the packing density, the amount of ethanol adsorbed per plate increases with the packing density reaching maximum at 750 kg/m³. This work shows the potential of using Maxsorb/ethanol in producing low temperature cooling down to ?15°C with specific cooling energy reaching 400 kJ/kg.     

A study of the blast wave shape from elongated VCEs

Elongated congestion patterns are common at chemical processing and petroleum refining facilities due to the arrangement of processing units. The accidental vapor cloud explosion (VCE) which occurred at the Buncefield, UK facility involved an elongated congested volume formed by the trees and undergrowth along the site boundary. Although elongated congested volumes are common, there have been few evaluations reported for the blast loads produced by elongated VCEs. Standard VCE blast load prediction techniques do not directly consider the impact of this congested volume geometry versus a more compact geometry.This paper discusses an evaluation performed to characterize the blast loads from elongated VCEs and to identify some significant differences in the resulting blast wave shape versus those predicted by well-known VCE blast load methodologies (e.g., BST and TNO MEM). The standard blast curves are based on an assumption that the portion of the flammable gas cloud participating in the VCE is hemispherical and located at grade level. The results of this evaluation showed that the blast wave shape for an elongated VCE in the near-field along the long-axis direction is similar to that for an acoustic wave generated in hemispherical VCEs with a low flame speed. Like an acoustic wave, an elongated VCE blast wave has a very quick transition from the positive phase peak pressure to the negative phase peak pressure, relative to the positive phase duration. The magnitude of the applied negative pressure on a building face depends strongly on the transition time between the positive and negative phase peak pressures, and this applied negative phase can be important to structural response under certain conditions. The main purpose of this evaluation was to extend previous work in order to investigate how an elongated VCE geometry impacts the resultant blast wave shape in the near-field. The influence of the normalized flame travel distance and the flame speed on the blast wave shape was examined. Deflagration and deflagration-to-detonation transition regimes were also identified for unconfined elongated VCEs as a function of the normalized flame travel distance and flame speed attained at a specified flame travel distance.     

安全史学的方法论研究

从历史研究发展和安全科学发展的角度分析安全史学研究的重要性和必要性。对安全史学的定义、安全史学认识系统结构、安全史学研究的特征进行综述,详细分析安全史学的研究对象及其分类。基于史学方法论原则和安全科学的方法论原则,总结了安全史学的方法论原则。分析安全史学研究的一般方法即归纳方法、比较方法和综合方法在安全科学研究中的应用,从安全史学研究资料的搜集和分析过程提出安全史学方法学。综合相关文献资料,结合马斯洛层次需求理论和系统论,提出基于人的需求层次的安全史学系统研究法及其应用,为安全史学研究的开展提供理论依据。     

华东电网电力供应及SO2排放预测

根据华东电网电力供需现状、一次能源资源情况、机组退役计划和区外来电情况以及负荷需求预测,重点分析了2005和2010年华东电网煤电机组的变化情况,并根据华东电网煤电机组现有的排放水平,对2005年上海、江苏和浙江的SO2排放进行预测.