两自由度摇摆台耦合动力学建模与仿真

考虑两自由度摇摆台内、外平台的耦合效应以及负载偏心造成的偏载力矩对驱动系统的影响,采用齐次变换方法建立了两自由度摇摆台的动力学模型。驱动系统采用齿轮齿条液压缸,考虑齿条间隙、液压流量非线性等影响,对液压伺服系统进行了仿真分析。仿真结果为驱动、控制系统的设计提供了参考依据。     

振动与力加载耦合电液系统的力加载跟踪控制

针对振动与力加载耦合电液系统因强耦合产生的干扰力问题,分析耦合系统的组成及工作原理,建立振动与力加载耦合电液系统的动力学模型;在此基础上,分析耦合电液系统干扰力的产生机制,提出带干扰观测器的前馈速度补偿控制策略;搭建振动与力加载耦合电液系统试验台,对提出的控制策略进行试验验证。试验结果证明提出的带干扰观测器的前馈速度补偿控制策略能够有效抑制系统干扰力,提高力加载跟踪精度。     

Oxidative coupling of methane over promoted strontium chlorapatite

Strontium zirconium phosphate, unpromoted strontium chlorapatite and strontium hydroxyapatite showed low C₂ selectivity for the oxidative coupling of methane, but promoted strontium chlorapatite catalysts showed markedly increased activity and selectivity and also exhibited stable behavior. SrCl₂ was the primary promoter and strontium zirconium oxides were considered to be acting as other promoters, but strontium zirconium phosphate and strontium carbonate seemed to be acting adversely. A promoted strontium chlorapatite catalyst which contained a slightly larger amount of SrCl₂ than needed to form the chlorapatite showed the best performance and was stable up to 50 h at 1,023 K, and the highest C₂₊ selectivity and yield were 52% and 13.8%, respectively. Although SrCl₂ was more stable than NaCl it decomposed slowly during the reaction, leaving strontium oxide or strontium carbonate behind, which is considered to result in slow deactivation of the catalyst.     

拘束度耦合模型计算管道焊接残余应力

焊接残余应力是造成焊缝开裂失效的主要原因,因而精确描述应力对于管道安全输送极为重要,而外加拘束是影响焊接应力分布的众多因素之一。为此,应用ANSYS仿真软件,采用实体—壳单元耦合建模方法,建立了拘束度与焊接过程的温度场和应力场耦合仿真模型,研究了拘束对油气管道焊缝应力的影响。同时,还基于自建的1套自拘束焊接试验装置,实现了不同拘束状态下管道的焊接,并通过应变仪采集焊接过程中的应力应变数据,与模拟结果进行对比,进而证明了ANSYS 仿真耦合模型的有效性。结果表明：①对于两端约束的钢管焊接对接接头,随着管长增加,焊缝处的轴向应力减小,在距离焊缝230 mm处的轴向应力亦减小;②焊趾处的塑性应变亦减小,整体焊接结构的拘束度降低;③焊接的管道残余应力随着拘束度的上升而增大,拘束情况对焊接残余应力的影响明显;④拘束度最大的0.5 m×0.5 m管子,其焊接残余拉应力最大可达140 MPa,高残余拉应力会严重削弱管道的整体性能。进而提出建议：加强管道建设期间的焊接施工管理,避免产生管道焊接时的强拘束。     

Simultaneous hydrogen production and utilization via coupling of Fischer-Tropsch synthesis and decalin dehydrogenation reactions in GTL technology

A thermally coupled membrane dual-type reactor (TCMDR) has been proposed for simultaneous hydrogen production and utilization in gas-to-liquid technology (GTL). Decalin dehydrogenation reaction is coupled with Fischer-Tropsch synthesis (FTS) reaction to improve the heat transfer between endothermic and exothermic sides. Furthermore, Pd-Ag and Hydroxy Sodalite membrane layers are assisted in TCMDR to improve the mass transfer between exothermic/endothermic side and permeation side. Some of the produced hydrogen via decalin dehydrogenation reaction is utilized in FTS reaction and the other is extracted and stored. The modeling results show 95% hydrogen production and 5% hydrogen utilization in FTS reactions in the exothermic reaction side of TCMDR configuration. The performance of TCMDR is compared with the one of conventional reactor (CR) and fluidized-bed membrane dual-type reactor (FMDR). Moreover, the gasoline yield in TCMDR increases about 17% and 29% in comparison with the one in FMDR and CR, respectively. The enhancement in gasoline and hydrogen yields demonstrates the superiority of TCMDR to the previous reactors.     

A cooling system for the secondary helium loop in VHTR-based SI hydrogen production facilities

Nuclear hydrogen production facilities consist of a very high temperature gas-cooled nuclear reactor (VHTR) system, intermediate heat exchanger (IHX) system, and a sulfur–iodine (SI) thermochemical process. This study focuses on the coupling system between the IHX system and SI thermochemical process. To prevent the propagation of the thermal disturbance owing to the abnormal operation of the SI process components from the IHX system to the VHTR system, a cooling system for the secondary helium of the IHX is required. In this paper, a conceptual flow diagram of the coupling system has been proposed. The temperature fluctuation of the secondary helium owing to the abnormal operation of the SI process was then calculated based on the proposed coupling system model. Finally, the conceptual design of the cooling system for the secondary helium of the IHX with a steam generator and forced-draft air-cooled heat exchanger to mitigate the thermal disturbance has been carried out.     

Design of a dual-drive mechanism for precision gantry

Gantry mechanisms have been widely used for precision manufacturing and material handling in electronics, nuclear, and automotive industries. Dual-drive servo mechanism is a way to increase control bandwidth, in which two primary axes aligned in parallel are synchronously driven by identical servo motors. With this mechanism, a flexible coupling (compliance mechanism) is often introduced in order to avoid the damage by the servo mismatch between the primary drives located at each side of gantry. This paper describes the design guidelines of the dual-drive servo mechanism with focus on its dynamic characteristics and control ramifications. That is, the effect on the system bandwidth which is critical on the system performance, the errors and torques exerted on guide ways in case of servo mismatch, the vibration characteristics concerned with dynamic error and settling time, and the driving force required at each axis for control are thoroughly investigated.     

电流变液及电流变液联轴器的实验研究

本文用沸石和硅油配制的电流变液，在圆筒式电流变液联轴器上测试了在有无电场作用下扭矩的传递能力。另外，调节外加电场得到在不同输入速度下联轴器的输出转速。实验表明，在确定负载和输入转速下，可以通过调节直流电场控制联轴器的输出转速，这为传动系统的无级调速提供了一种新的简便的手段。     

炸药件加成型硅橡胶包覆技术研究

针对加成型硅橡胶包覆炸药件催化剂中毒以及脱粘问题,对影响加成型硅橡胶硫化过程的因素及其粘接性开展研究。结果表明：防中毒剂异丙醇铝可较好解决炸药加成型硅橡胶包覆催化剂中毒的问题;催化剂种类及加料顺序对硫化速度有一定影响;适当的硅烷偶联剂以及适宜的表面处理方法可有效改善加成型硅橡胶对炸药的粘接性能。     

大功率激光两分束无源耦合器的优化设计

介绍了大功率激光两分束无源耦合器的优化设计原理及方法,采用芯径φ105/125阶跃多模纯石英光纤,设计、试制成大功率激光两分束无源耦合器.用小型化固体激光器和LPE-1B激光能量/功率计,测定了两分束器的激光能量耦合、传输参数,结果表明总耦合率达到81.27%.