弹簧直接载荷式安全阀升力特性计算方法

运用CFD方法,采用标准和Realizable两种湍流模型对安全阀升力特性进行数值计算。通过升力测量试验验证计算结果,讨论了安全阀升力特性曲线,并确定合适的升力计算方法。     

改进水煤浆气化工艺装置的一些思考

针对水煤浆气化工艺技术存在的一些问题,从工艺烧嘴的结构、材料改进及工艺技术的发展等方面提出了改进措施和建议,并对部分改进措施实施后的效果进行了分析,介绍了水煤浆的分级气化技术及相应的原料供应烧嘴（工艺烧嘴和二次补氧烧嘴）的设计方案和设计准则。     

水煤浆气化炉工艺烧嘴有关问题的探讨

工艺烧嘴损坏是水煤浆气化炉不能长周期运行的主要原因。导致烧嘴损坏因素主要有冷却水盘管损坏、物理磨蚀、热冲击、化学影响、应力破坏等。提出了改进措施以延长烧嘴的使用寿命,主要包括降低流速、改进材质、优化结构等。     

低温推进剂输送管路热动力排气系统研究

为了实现低温推进剂的长期在轨贮存,保证推进剂从贮箱到发动机的液态供应,拟采用热动力排气系统(Thermodynamic Vent System,TVS)来实现推进剂的热管理。以单位长度液氧管路为例,阐述了热动力排气系统的原理,进行热动力排气系统孔板及TVS管路设计、在轨贮存时间计算、TVS管路排放量计算以及排放量影响因素分析。     

Fabrication of novel ZnTe-based photocatalyst: Synergistic effect of dye sensitization and bridge engineering for boosting hydrogen evolution over ZnTe

Herein, a novel ZnTe-based photocatalyst is successfully synthesized via a facile combination of water-bath and hydrothermal processes. Morphology characterization and X-ray diffraction analysis reveal that ZnTe presents irregular granular shape and cubic crystal structure. Moreover, Mott-Schottky measurement shows that the conduction band potential of ZnTe is ?0.84 V (vs NHE). With Eosin Y (EY) sensitization, ZnTe exhibits superior photocatalytic hydrogen evolution activity (223.5 μmol g^?1 h^?1). Meanwhile, WC-ZnTe heterojunction is constructed by depositing ZnTe nanoparticles on bulk WC and obtains the optimal H₂ generation rate (559.1 μmol g^?1 h^?1) under EY sensitization. Electrochemical and photoluminescence results further prove that WC as electron bridge could reduce the interfacial resistance and suppress e^?-h⁺ pairs recombination. This study explores the potential application of ZnTe as a newly active photocatalyst in photocatalytic water splitting, and emphasizes the synergistic effect of dye sensitization and bridge engineering.     

用于低压储罐保护的压力真空泄放阀

介绍了压力真空泄放阀的工作原理、类型及口径的确定。     

大型火箭发动机试验导流槽热防护设计

火箭发动机热试车时喷射出的高温高速气流具有很大的冲击力和腐蚀力。导流槽的作用就是将燃气迅速地导向远离试车台的地方,防止火焰、烟尘及碎片反射回来冲击试验台,毁坏发动机和设备。随着我国大推力运载火箭研制立项,导流槽烧蚀的问题日益严峻。本文提出了一种新型导流槽热防护技术方案:通过数值分析和工程计算分析导流槽力、热环境;基于膜冷却原理,采用分区喷流水冷却的方法,根据热流密度不同在各区域采取不同的供水方式。此方案在保证导流槽冷却系统可靠性的同时,降低了试验台高度、节约了水资源。     

Effects of rare-earth oxide doping on the thermal radiation performance of HfO2 coating

In this study, the REO-HfO₂ (REO = Tb₄O₇, Gd₂O₃ and Sm₂O₃) coatings and pure HfO₂ coatings were prepared by atmospheric plasma spraying. The chemical compositions, morphologies, infrared radiation performance and thermal resistances of the coatings were systematically investigated. The experimental results showed that the Tb₄O₇-HfO₂, Gd₂O₃-HfO₂, Sm₂O₃-HfO₂ and pure HfO₂ coatings had infrared emissivity values of 0.863, 0.852, 0.854 and 0.621, respectively, at room temperature. Based on the phase analysis, the higher infrared emissivity of the REO-HfO₂ coatings could be attributed to the fact that the newly formed RE₂Hf₂O₇ (RE = Tb, Gd and Sm) phase, which had a defective fluorite-type structure, and the RE³⁺ ions enhanced the lattice absorption and electron absorption. Additionally, the Tb₄O₇-HfO₂ coating exhibited a relatively higher infrared emissivity than those of the Gd₂O₃-HfO₂ and Sm₂O₃-HfO₂ coating over the wavelength range of 1–15 μm, which was due to the relatively higher vibrational frequency of the TbO bond in RE₂Hf₂O₇ (RE = Tb, Gd and Sm) and the transformation of Tb³⁺ into Tb⁴⁺ in the Tb₄O₇-HfO₂ system. In addition, the REO-HfO₂ ceramic coatings exhibited excellent thermal resistance, which could withstand high-temperature treatment at 1600 °C for at least 50 h without undergoing a phase change and exfoliation, and the infrared emissivity at different temperatures hardly changed after thermal treatment.     

Experimental research of drop‐on‐demand droplet jetting 3D printing with molten polymer

Three‐dimensional (3D) printing technology has become an effective method for parts manufacturing and got a certain application in many fields. Now, drop‐on‐demand droplet jetting 3D printing appears as a new method of manufacturing technology which has a proven research progress for metal, colloid, and liquid resin materials. However, there are hardly any researches of droplet jetting 3D printing with molten polymer. So, considering molten polymer as the jetting material with droplet jetting method is an explorative direction. In order to attain the molten polymer droplets and achieve droplet jetting 3D printing with molten polymer, the 3D printing technology of differential melt (3DPDM) is developed independently. According to 3DPDM, a complete set of drop‐on‐demand droplet jetting 3D printer have been developed. In this work, PP (6820) was chosen as the experimental material. Under the different print parameters such as the rotation speed of screw, nozzle diameter, mechanical impact frequency, heating temperature, the space between nozzle and platform, the form, and deposition of droplets were studied. Furthermore, the optimal print parameters were summarized. By printing models with the optimal print parameters, it turned out that the 3DPDM is able to achieve drop‐on‐demand droplet jetting 3D printing with molten polymer. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45933.     

基于红外技术的液体火箭发动机尾焰流场测量研究

利用傅里叶红外光谱仪（FTIR）和热像仪对常规液体火箭发动机尾焰流场红外光谱和图像进行了测量研究。红外光谱检测出了尾焰流场中的主要燃烧产物H2O、CO2以及微量燃烧产物NO、N2O。红外图像捕捉到了尾焰流场结构,建立了图像特征与燃烧状态之间的关系。研究结果表明:红外光谱仪和红外热像仪可对尾焰特征燃烧产物、流场结构进行精确测量,红外技术的应用为发动机工作状态监测提供一种新的分析手段。