Fluid-solid coupling numerical simulation of charge process in variable-mass thermodynamic system

A joint solution model of variable-mass flow in two-phase region and fluid-solid coupling heat transfer, concerned about the charge process of variable-mass thermodynamic system, is built up and calculated by the finite element method (FEM). The results are basically consistent with relative experimental data. The calculated average heat transfer coefficient reaches 1.7×10⁵ W/(m² · K). When the equal percentage valve is used, the system needs the minimum requirements of valve control, but brings the highest construction cost. With the decrease of initial steam pressure, the heat transfer intensity also weakens but the steam flow increases. With the initial water filling coefficient increasing or the temperature of steam supply decreasing, the amount of accumulative steam flow increases with the growth of steam pressure. When the pressure of steam supply drops, the steam flow gradient increases during the maximum opening period of control valve, and causes the maximum steam flow to increase.     

基于神经网络的变流量管路摩阻系数计算

应用改进的BP神经网络算法对过渡区内流量变化下的蒸汽管路摩阻系数进行了预测,解决了因蒸汽流量变化而使得摩阻系数值计算过程复杂繁琐、效率低下的问题。实例表明,该方法得到的仿真值与Colebrook方程计算值符合较好,所产生的误差平均水平能够满足工程计算的精度要求。     

Simulation modeling and experimental analysis of thermodynamic charge performance in a variable-mass thermodynamic system

The thermodynamic charge performance of a variable-mass thermodynamic system was investigated by the simulation modeling and experimental analysis. Three sets of experiments were conducted for various charge time and charge steam flow under three different control strategies of charge valve. Characteristic performance parameters from the average sub-cooled degree and the charging energy coefficient point of views were also defined to evaluate and predict the charge performance of system combined with the simulation model and experimental data. The results show that the average steam flow reflects the average sub-cooled degree qualitatively, while the charging energy coefficients of 74.6%, 69.9% and 100% relate to the end value of the average sub-cooled degree at 2.1, 2.9 and 0 respectively for the three sets of experiments. The mean and maximum deviations of the results predicted from those by experimental data are smaller than 6.8% and 10.8%, respectively. In conclusion, the decrease of average steam flow can effectively increase the charging energy coefficient in the same charge time condition and therefore improve the thermodynamic charge performance of system. While the increase of the charging energy coefficient by extending the charge time needs the consideration of the operating frequency for steam users.     

备件配置优化方法的相关研究现状

备件是舰船海上执行任务的重要保障资源,备件配置的好坏关系到舰船任务成功性的完成。针对舰船出海备件配置量的问题,分析和研究了当前国内外配置的研究概况,重点对备件在定量和定性变量约束下的备件配置优化方法进行了研究。结合目前已有文献基础,对未来可以进行重点研究的配置优化问题进行了展望。     

激光雷达风速模拟系统设计

多普勒测风激光雷达是大气风场探测的重要手段。本文以光纤Mach-Zehnder干涉仪作为测风激光雷达系统的鉴频器,设计并建立了风速模拟探测激光雷达的自校正式实验系统,采用可控转速机械转轮产生的线速度引起激光多普勒频移的方法模拟大气风场。其主要由激光发射系统、模拟风场系统和光电探测系统组成。初步利用种子激光器的可调节波长实现了系统输出强度变化,通过能量探测方式验证了光纤Mach-Zehnder干涉仪透过率谱强度曲线,实验分析结果验证了鉴频系统的可靠性,并进一步实现了鉴频系统光程差精确校正。     

装备综合保障包评价方法研究

开展装备综合保障包评价方法研究的目的,是从要素、特性、数据以及信息等几个角度定量和定性的对综合保障包的生成过程及成果予以评价,论证并分析保障包评价实施的过程、指标体系和评价模型,为后续装备保障包的研制和使用单位提供评价方法和技术支撑。本文根据美军装备综合保障理论研究的最新成果,通过系统研究美军装备综合保障系统的相关文献及相关系统的开发经验,在综合保障包理论研究、研制要求和研究成果的基础上,主要研究构建了装备综合保障包技术体系所需的有效的评价方法,同时研究了如何开展综合保障包的评价工作,明确了评价的主体和客体、评价目标、评价步骤、评价内容和评价方法。通过上述研究,构建了装备综合保障包技术体系所需的评价方法,并将其应用于装备综合保障体系中,解决了评价指标和评价标准模糊性的问题,既克服了人为主观臆断,又使评价结果更加科学准确,为新体制下装备综合保障体系建设的进一步发展提供了参考和支撑。     

Modeling and simulation of dynamic performance of horizontal steam-launch system

Based on theory of variable-mass system thermodynamics, the dynamic mathematic models of each component of the horizontal steam-launch system were established, and by the numerical simulation of the system launching process, the thermodynamics and kinetics characteristics of the system with three valves of different flow characteristics were got. The simulation results show that the values of the peak-to-average ratios of dimensionless acceleration with the equal percentage valve, the linear valve and the quick opening valve are 1.355, 1.614 and 1.722, respectively, and the final values of the dimensionless velocities are 0.843, 0.957 and 1.0, respectively. In conclusion, the value of the dimensionless velocity with the equal percentage valve doesn＇t reach the set value of 0.90 when the dimensionless displacement is 0.82, while the system with the linear valve can meet the launching requirement, as well as the fluctuation range of dimensionless acceleration is less than that of the quick opening valve. Therefore, the system with the linear valve has the best performance among the three kinds of valves.