Penetration Analysis of Concrete Plate by 3D FE-SPH Adaptive Coupling Algorithm

Penetration process of concrete plate is simulated by 3D FE-SPH adaptive coupling algorithm, which is based on experimental research of projectile with 25mm diameter penetrates concrete target. In experiment, a high speed camera is used to record dynamic deformation process of concrete plate. Acceleration responses of concrete are obtained by acceleration sensor, which is pre-embedded in target plate. This experiment is also simulated by 3D FE-SPH adaptive coupling algorithm to verify the numerical model. Numerical model is approximated initially by FEM, and distorted elements are automatically converted into meshless particles to simulate damage, splash of concrete by SPH method, when equivalent plastic strain of elements reaches a specified value. Numerical results of damage process and acceleration response of concrete target are in good agreement with the experimental results. And the results show that crack propagation and lateral movement of concrete mainly occur after projectile passing through target. Furthermore, six different models with different geometry sizes are simulated by the coupling algorithm to study on the effects of boundary condition of concrete target.     

排气消声器温度场数值仿真与分析

建立消声器和外界环境的耦合传热计算模型,并使用Fluent软件计算简单膨胀腔消声器的温度场,分析消声器内外温度分布的形成原因及气流速度对温度场的影响。在此基础上,计算双进口消声器在某一工况下的温度分布。     

微波单端口网络的群时延研究

针对单端口微波网络的群时延特性、并联谐振与串联谐振两种谐振器,在单端口网络中的群时延特性做了推导。得到群时延特性中S参数与谐振腔品质因数之间的关系,分析了两种负载情况下群时延特性的变化情况,得出单端口网络不随负载变化而变化的结果,有助于研究谐振器的外部耦合特性。     

Effect of alkyl nitrite decomposition on catalytic performance of CO coupling reaction over supported palladium catalyst

The syntheses of dimethyl oxalate (DMO) and diethyl oxalate (DEO) by CO coupling reaction in gaseous phase were investigated in a fixed bed reactor over Pd-Fe/Al₂O₃ catalyst. The catalytic performance was characterized by CO conversion, space-time yield (STY) and selectivity of DMO (or DEO). The results showed that over Pd-Fe/Al₂O₃ catalyst, the STY of DMO was higher than that of DEO under the same reaction conditions. The optimum reaction temperatures for synthesizing DMO and DEO were 403 K and 393 K, respectively, at the molar ratio 1 ∶ 1 of alkyl nitrite to CO. The difference in synthesizing DMO and DEO on the same catalyst was attributed to the decomposition performances of methyl nitrite (MN) and ethyl nitrite (EN), as density functional theory (DFT) calculation showed that EN decomposed more easily than MN.     

相变热控装置内部的传热特性

针对舱内热控用相变热控装置内部的传热特点,研究装置内相变材料吸热过程的相变传热及流固耦合传热规律,建立了相应的数理模型及数值计算方法,进行了实验验证,并在此基础上分析了典型热控单元吸热特性的影响因素及作用规律。相关研究成果将为相变热控装置吸热及热控特性的有效预测,以及为装置的设计及优化提供参考。     

基于离散介质流固耦合理论的地下石油洞库水封性和稳定性评价

 以我国首个大型地下水封石油洞库工程为背景,基于离散介质流固耦合理论,开展地下石油洞库水封性和稳定性评价。通过室内岩石三轴试验和结构面剪切–渗流耦合试验,获得岩石的弹性模量、泊松比和结构面的剪切模量、水力开度等参数。根据施工巷道开挖过程中围岩变形和水位变化情况,对围岩参数进行反分析,获得较为可靠的洞库围岩参数。综合上述成果,分析地下石油洞库的水封性和稳定性特征。研究发现,在水幕压力为50 kPa条件下,该地下水封石油洞库稳定水位位于主洞室上方约60 m,且大于洞内储存介质的压力,满足洞库水封条件;洞库各主洞室位移为9～30 mm,达到洞室稳定相关控制标准;分析8#和9#主洞室边墙附近的水平应力、竖向应力、法向应力和切向应力的变化,并将其划分为3个区域,即松动区、扰动区和未扰动区,其中洞室松动区范围约为6 m。研究为大型地下石油洞库水封性和稳定性评价提供理论依据。     

低渗砂岩储层岩石学特征与应力敏感性耦合关系——以鄂尔多斯盆地苏里格-吉尔地区下石盒子组八段下亚段为例

低渗油气藏主要采取衰竭式开发,地层压力得不到补充,储层的应力敏感性问题显得尤为突出。以鄂尔多斯盆地苏里格-吉尔地区下石盒子组八段下亚段为例,依靠详细的井下地质调查、岩心精细描述、系统取样配套测试及室内比对分析等方法,对岩石学特征与应力敏感性耦合关系进行精细解剖,发现目的层位岩石类型主要为岩屑石英砂岩,其次为硅质石英砂岩以及少量岩屑砂岩。样品采用CMS-400型高压孔渗分析仪测试,初始渗透率普遍偏低,应力敏感性中等偏强,两者呈明显的正相关关系。岩石组分中,柔性岩屑和基质硬度及稳定性低,在外力作用下易变形、破碎和位移,其含量与应力敏感性呈正相关关系。碎屑石英、刚性岩屑及石英、铁绿泥石等胶结物硬度和稳定性高,在外力作用下变形弱,其含量与应力敏感性呈负相关关系。不同岩类因岩石学特征差异间接导致应力敏感性不同,在开发过程中可采用不同级别的生产压差求得油田的最优产能。     

光纤型半导体激光器线阵工艺研究

采用计算机控制技术、激光器调制技术、光纤耦合技术、微透镜聚焦技术,研究了半导体激光器的线阵.利用线阵组合原理展示了半导体激光器线阵技术的原理和实现过程,扩展了线阵技术在快速成型、显示技术等方面的应用领域.     

锚网-锚索耦合桁架支护技术在泉店煤矿的应用

巷道围岩岩性松散、破碎,应力集中程度较高,围岩体整体强度偏低,在高应力作用下巷道围岩剪胀变形较为强烈,局部承载结构破坏诱发锚网支护大面积失效,承载结构稳定性降低。实施锚网—锚索耦合支护技术,根据位移分析原理,确定支护系统二次耦合支护的最佳时间(段),在关键部位实施支护体和围岩的再次耦合,最大限度地发挥围岩的承载能力,从而使支护体的支护抗力降到最小。     

纳米二氧化硅表面改性的研究

用硅烷偶联剂KH-550、钛酸酯偶联剂NDZ-201和硬脂酸处理纳米二氧化硅,并对改性效果进行了比较。结果表明,硅烷偶联剂和钛酸酯偶联剂对纳米二氧化硅的改性效果明显优于硬脂酸,而硅烷偶联剂的修饰效果最好。硅烷偶联剂改性纳米二氧化硅的最佳工艺条件为KH-550用量为4%,反应时间为2h,反应温度为110℃,此工艺条件下,亲油化度可达58.32%,吸水率可达3.03%,且分散稳定性良好。