基于传统清管球接收器的滤杂防堵工艺设计

清管球回收操作过程中,清管球接收器的泄压、排液和惰化导致泥、砂、垢等杂质积聚在清管球接收器中,并随油气物流进入闭排系统管线,造成杂质流失、闭排系统管线堵塞和压力无法完全释放,影响对海底油气管道腐蚀、析蜡、结垢及地层出砂等情况的判断,存在很大的安全隐患。通过对清管球接收器实施工艺改造,使清管球接收器具备滤杂防堵功能和自动取样功能,有效解决了闭排管线堵塞、杂质流失和安全隐患问题。该工艺研究对于海上油气田海底管线的运营和维护具有较高的借鉴意义。     

基于船载卫星通信三轴天线的跟踪搜索技术

针对船载卫星通信三轴天线跟踪系统,介绍了船载三轴天线的系统组成,提出了一种基于捷联惯导的船载三轴天线跟踪搜索技术。天线以目标地理角为中心,通过坐标转换将目标地理角转换为天线的目标甲板角,调整AEC三轴使其及时准确地跟随目标甲板角。目前,该方法已经成功应用于多种船载三轴天线。实践表明,该方法能够快速准确地搜索到目标卫星,并实现对目标卫星的稳定跟踪。     

宽带数字接收机IQ不平衡估计与自适应补偿算法

针对宽带调制解调技术中广泛存在的IQ不平衡问题,在IQ不平衡模型及补偿原理的分析基础上提出了一种宽带数字接收机IQ不平衡估计与自适应补偿算法。首先利用解调数据对IQ不平衡参数进行实时估计,然后利用估计参数对接收信号进行自适应补偿。实验结果表明,所提算法可以有效解决宽带调制解调系统中普遍存在的IQ不平衡问题,提升系统误码性能。     

Numerical modelling and optimisation of natural convection heat loss suppression in a solar cavity receiver with plate fins

This study details the numerical modelling and optimization of natural convection heat suppression in a solar cavity receiver with plate fins. The use of plate fins attached to the inner aperture surface is presented as a possible low cost means of suppressing natural convection heat loss in a cavity receiver. In the first part of the study a three-dimensional numerical model that captures the heat transfer and flow processes in the cavity receiver is analyzed, and the possibilities of optimization were then established. The model is laminar in the range of Rayleigh number, inclination angle, plate height and thickness considered. In the second part of the study, the geometric parameters considered were optimized using optimization programme with search algorithm. The results indicate that significant reduction on the natural convection heat loss can be achieved from cavity receivers by using plate fins, and an optimal plate fins configuration exit for minimal natural convection heat loss for a given range of Rayleigh number. Reduction of up to a maximum of 20% at 0° receiver inclination was observed. The results obtained provide a novel approach for improving design of cavity receiver for optimal performance.     

Assessing the impact of non-ideal optical factors on optimized solar dish collector system with mirror rearrangement

An optimized solar dish collector (OPSDC) system was proposed in our previous work, which can achieve excellent the optical efficiency and flux uniformity under ideal optics. On this basis, the impacts of the non-ideal optical factors on the optical performance of OPSDC system with a cylindrical and conical receiver are studied in detail and compared with the conventional solar dish collector (COSDC) system in this paper. Where the non-ideal optical factors considered are relatively comprehensive, including the mirror slope error, tracking error, installation error of the mirror and receiver, and receiver's absorptivity degeneration. An optical model with the non-ideal optical factors is built in detail by the ray tracing method, and the corresponding ray tracing codes are developed and verified by literatures and optical software OptisWorks 2012. The results show that the OPSDC system not only has a significantly smaller peak local concentration ratio (LCR) and non-uniformity factor than the COSDC system under the same non-ideal optical factor, but also has excellent optical performance. This means that OPSDC system can effectively avoid the heat absorber generating high-temperature hot spots, thus significantly improving its working reliability and service lifetime. In addition, the tracking error, installation error of the receiver and mirror all lead to the increase of the peak LCR and non-uniform factor, while the mirror slope error and absorber's absorptivity degeneration are conducive to reducing the peak LCR and non-uniform factor. This work can provide a reference for error control of COSDC system and OPSDC system in manufacturing, installation and operation.     

Potential of performance improvement of concentrated solar power plants by optimizing the parabolic trough receiver

This paper proposes a comprehensive thermodynamic and economic model to predict and compare the performance of concentrated solar power plants with traditional and novel receivers with different configurations involving operating temperatures and locations. The simulation results reveal that power plants with novel receivers exhibit a superior thermodynamic and economic performance compared with traditional receivers. The annual electricity productions of power plants with novel receivers in Phoenix, Sevilla, and Tuotuohe are 8.5%, 10.5%, and 14.4% higher than those with traditional receivers at the outlet temperature of 550°C. The levelized cost of electricity of power plants with double-selective-coated receivers can be decreased by 6.9%, 8.5%, and 11.6%. In Phoenix, the optimal operating temperature of the power plants is improved from 500°C to 560°C by employing a novel receiver. Furthermore, the sensitivity analysis of the receiver heat loss, solar absorption, and freeze protection temperature is also conducted to analyze the general rule of influence of the receiver performance on power plants performance. Solar absorption has a positive contribution to annual electricity productions, whereas heat loss and freeze protection temperature have a negative effect on electricity outputs. The results indicate that the novel receiver coupled with low melting temperature molten salt is the best configuration for improving the overall performance of the power plants.     

受油机扰动特性的建模与仿真

针对紧密编队飞行过程中产生的尾涡流场对空中加油机产生扰动影响的问题,建立了受油机扰动运动模型。将风扰动主要分解为大气紊流和加油机尾涡,分别建立工程化的Dryden大气紊流模型和尾涡模型,将叠加的2个扰动加入到受油机的非线性刚体运动方程中,并对受油机扰动运动进行仿真分析。仿真结果表明：该叠加的方法能够简单有效地模拟反映复杂的气流扰动,为进一步研究空中加油控制系统提供参考。     

GPS 信号接收机的新近发展

自1980年第一台商品GPS信号接收机问世以来,GPS信号接收机不断更新换代,日新月异。综析了GPS信号接收机的新近发展,主要表现在下述方面:用软件无线电技术实现GPS信号接收机的软件化;用蓝牙技术实现GPS数据的无线传输;用通用无线分组业务(GPRS)扩展RTK移动站的作用距离;用SAASM技术直接捕获和跟踪P码;用内置增强跟踪技术研制成GPS/WAAS/EGNOS集成接收机。     

突发接收模块的接收特性研究

介绍了衡量接收特性的误码函数和Q因子,并以此为基础对突发接收模块中影响接收特性的因素,如判决电平偏离理想值、信号的消光比、信号间干扰、带宽滤波效应等进行了研究分析,对突发接收模块的设计具有重要意义.     

1.5GHz CMOSECL输入接口的设计与测试

对一种高速CMOS ECL输入接口进行了分析研究,该接口包含一种双镜补偿的CMOS差分放大电路,采用0.18 μm CMOS工艺研制,实现了PECL电平兼容.经测试,该接口最高工作频率达1.5 GHz.