特种循环冷却装置控制系统研究

介绍了特种循环冷却装置系统构成与工作原理,分析了该机组控制系统的应用,研究了该机组控制参数与被控制点的突变特性,提出了科学的控制方法。     

Multiple Methods for Determining Stability of Attenuating MTBE Groundwater Plume

A gasoline release site at the Dept. of Defense Housing Facility (DODHF) in Novato, Calif., resulted in dissolved methyl tertiary-butyl ether (MTBE) in a shallow, thin, heterogeneous aquifer. Multiple methods were used to evaluate the stability of the MTBE plume, including concentration versus time plots, isoconcentration contour maps, total dissolved MTBE mass and center of mass (COM) estimates, total plume extent changes, and parametric and nonparametric statistical techniques. The COM evaluation revealed a small upgradient shift in COM relative to both total plume extent and total MTBE mass reduction over the period examined. The total mass removal received substantial contributions from both the southern and northern portions of the plume, and the only removal mechanisms active in the northern plume were natural attenuation mechanisms. The results indicate that there exists at DODHF Novato a dissolved MTBE plume at the approximate balancing point between groundwater advection, which is carrying MTBE downgradient, and natural attenuation processes including aerobic biodegradation, which are reducing MTBE concentrations at about the same rate.     

增压锅炉烟气净化器试验与仿真对比分析

保证锅炉涡轮增压机组燃气轮机可靠工作的重要部件是烟气净化器。根据净化器的实际工作环境和特点,通过建立试验模型,使用树脂小球、聚苯乙烯小球和小米三种试验颗粒模拟烟气颗粒进行试验,应用试验和仿真两种手段对烟气净化器的分离效率和影响因素进行了分析。通过综合归纳和整理,得出了模拟试验与仿真相吻合的分离效率和影响因素。     

舰船导航系统CAN总线网络设计关键技术的研究

针对舰船传统导航系统中通讯方式的不足,提出了基于CAN总线的导航系统网络化方案,在理论上进行了双冗余CAN网络结构的设计;传统导航系统内部都是通过串行口的方式实现综合导航显控台和各信息传感器之间的信息通讯;由于这种传输方式自身的缺陷,已经不能满足导航系统不断发展的需求;导航系统网络化方案的提出,迎合了系统发展的需求,在该方案中,综合导航显控台、各导航传感器及导航设备都挂接CAN总线上,利用CAN总线这个开放统一的接口形式可以很好实现各导航设备与舰上其它系统的信息共享,提高整个导航系统的自动化与可靠性;最后,通过MATLAB仿真,从一定程度上验证了基于CAN总线的导航系统网络化方案的可行性.     

舰船柴油主机滑油系统贝叶斯网络推理故障诊断方法

以舰船动力装置中的柴油主机滑油管路系统为研究对象,针对滑油系统故障诊断问题,分析了常见故障机理,建立了滑油系统常见故障的故障树结构,在此基础上构建了用于故障状态推理的贝叶斯网络模型,分析了滑油系统典型故障状态下的贝叶斯状态推理过程,为滑油系统的快速故障诊断提供了一种新的方法。     

基于均值滤波矩阵组的二维信号快速经验模式分解方法

 根据矩阵变换理论,提出了一种基于滤波矩阵组的局部均值求取方法.该方法构造了均值滤波矩阵组,只需在待处理矩阵左右各乘一个均值滤波阵,即可得到待处理阵的加权均值,简化了包络均值求解过程.在上述局部均值滤波理论的基础上,提出了二维信号的快速经验模式分解算法.实验证明,算法运算时间比传统经验模式分解方法提高了两到三个数量级.     

Energy exchange at a sea ice boundary

Energy exchange at the surface of an annual sea ice sheet was computed for five days, during the winter of 1959, from values of the following energy components: radiant flux, conducted flux, sensible flux and latent flux. These were obtained by measurement and by application of the theories of Priestley and Crawford. The latter performed well in adverse changing weather conditions, over the stability range of Richardson's numbers between −0·053 and +0·140. The energy components for a relatively cloudless day were compared with those for an overcast day, demonstrating significant changes in the total net radiation at the ice surface due to cloud cover. It was found that open leads forming in the ice release large amounts of energy from the ocean to the atmosphere. This energy is then transmitted to other areas, modifying the weather in those areas. The energy component with the largest uncertainty is the latent flux. All hourly measured values of latent energy were compared with the flux as determined by the remainder method. This comparison was used as an indication of the total energy balance error.     

Development of deep-ocean work system

The Navy is developing a deep-ocean work system comprised of manipulators and a variety of hydraulic tools integrated to accomplish meaningful work tasks to ocean depths of 20,000 ft. The system can readily adapted to the manned submersibles ALVIN, SEACLIFF, and TURTLE, and the robot vehicles CURV III and RUWS, to extend their work capability. In addition, it can be positioned and controlled by divers or operated by itself from a surface support ship. The system was designed to perform a complete work operation on the sea floor without the necessity of resurfacing for tool interchange. Potential tasks include recovery, construction, installation, and repair operations. Low-light level TV cameras, with quartz-iodide flood lights, augment the vehicle operator's vision for tool exchange and work operations.     

基于高速开关阀的电液振动冲击系统的研究

提出一种基于高速开关阀的电液振动冲击式剁锉机的液压系统,利用AMESim软件建立系统的仿真模型,分析系统的动态特性,探讨系统各主要结构参数对冲击能的影响.结果表明:调整系统压力ps、控制信号占空比τ和控制信号频率f,分别在2～7 MPa、0.1～1和4～20 Hz范围内,可以有效地控制冲击能的大小;在满足剁锉频率的基础上,增加活塞质量m,能有效提高冲击能;蓄能弹簧预压缩量x0和刚度k有优化范围,分别为x0=10～40 mm和k=40～108 N/mm.在仿真分析的基础上,研制剁锉机样机,并进行相关实验和试生产.结果表明,该系统能够满足实际生产的需要.     

永磁屏蔽式耐高压高速开关电磁铁

为了提高电磁力、加快响应速度,提出一种永磁屏蔽式耐高压高速开关电磁铁,采用NdFeB稀土永磁材料作为磁屏蔽元件,减少漏磁并加快了动态响应.基于有限元方法建立电磁铁的动态数学模型,并通过实验进行验证,实验与仿真基本吻合,响应误差为3.2%,验证模型的有效性.在此基础上,对该高速开关电磁铁进行动态仿真,探讨永磁体长度、厚度、激磁方向,盆口高,耐压环厚度,隔磁片长度,前隔磁角和后隔磁角等结构参数对响应时间的影响规律.结合实际设计要求,结果表明,采用优化后的结构参数研制的永磁屏蔽式耐高压高速开关电磁铁在0.6 mm行程时的响应时间为2.20 ms.