Integrated design optimization of spar floating wind turbines

A linearized aero-hydro-servo-elastic floating wind turbine model is presented and used to perform integrated design optimization of the platform, tower, mooring system, and blade-pitch controller for a 10 MW spar floating wind turbine. Optimal design solutions are found using gradient-based optimization with analytic derivatives, considering both fatigue and extreme response constraints, where the objective function is a weighted combination of system cost and power quality. Optimization results show that local minima exist both in the soft-stiff and stiff-stiff range for the first tower bending mode and that a stiff-stiff tower design is needed to reach a solution that satisfies the fatigue constraints. The optimized platform has a relatively small diameter in the wave zone to limit the wave loads on the structure and an hourglass shape far below the waterline. The shape increases the restoring moment and natural frequency in pitch, which leads to improved behaviour in the low-frequency range. The importance of integrated optimization is shown in the solutions for the tower and blade-pitch control system, which are clearly affected by the simultaneous design of the platform. State-of-the-art nonlinear time-domain analyses show that the linearized model is conservative in general, but reasonably accurate in capturing trends, suggesting that the presented methodology is suitable for preliminary integrated design calculations.     

米勒循环结合可变涡轮增压优化柴油机性能的仿真与试验研究

在开发一款机车柴油机过程中,利用AVL BOOST软件对柴油机工作过程进行了仿真计算,计算了不同米勒强度和不同喷油正时条件下柴油机的性能参数。根据计算结果,排除了弱米勒的方案。针对强米勒和中米勒,开展了试验研究,通过调整喷油定时、增压压力设定、共轨喷射压力,进行了多方案试验研究,试验结果表明,强米勒方案虽然可以有效降低Nox排放,但是带来PM排放升高和涡轮前排气温度升高的问题,中米勒虽然降低Nox排放的效果弱于强米勒,但是能获得比较满意的PM排放,且涡轮前排气温度远低于强米勒,综合各方面性能参数的比较结果,在满足排放要求的前提下,中米勒为优选方案。     

减摇鳍海水冷却器防腐防漏优化

海水冷却器在减摇鳍系统中占据举足轻重的地位,决定了设备是否可正常使用。受各类因素的影响,海水冷却器在使用过程中易发生漏水问题,致使油液被乳化,加剧液压零部件的磨损,从而严重影响液压系统的安全与长期稳定运行。而检修作业将对船舶舱内环境产生较大的破坏,增加运营维护成本,解决漏水问题迫在眉睫。文章主要对漏水原因进行分析,并加以优化,提高液压系统的可靠性。     

Joint deployment of charging stations and photovoltaic power plants for electric vehicles

The focus of this study is to jointly design charging stations and photovoltaic (PV) power plants with time-dependent charging fee, to improve the management of the coupled transportation and power systems. We first propose an efficient and extended label-setting algorithm to solve the EV joint routing and charging problem that considers recharging amount choices at different stations and loop movement cases. Then, a variational inequality problem is formulated to model the equilibrium of EV traffic on transportation networks, and an optimal power flow model is proposed to model the power network flow with PV power plants and optimally serve the EV charging requirements. Based on the above models for describing system states, we then formulate a model to simultaneously design charging stations, PV plants, and time-dependent charging fee. A surrogate-based optimization (SBO) algorithm is adopted to solve the model. Numerical examples demonstrate that the proposed SBO algorithm performs well. Additionally, important insights concerning the infrastructure design and price management of the coupled transportation and power networks are derived accordingly.     

The symmetric intersection design and traffic control optimization

It is well recognized that the left-turning movement reduces the intersection capacity significantly, because exclusive left turn phases are needed to discharge left turn vehicles only. This paper proposes the concept of Left-Hand Traffic (LHT) arterial, on where vehicles follow left-hand traffic rules as in England and India. The unconventional intersection where a LHT arterial intersects with a Right-Hand Traffic (RHT) arterial is named as symmetric intersection. It is only need three basic signal phases to separate all conflicts at symmetric intersection, while it at least need four signal phases at a conventional intersection. So, compared with the conventional intersection, the symmetric intersection can provide longer green time for the left-turning and the through movement, which can increase the capacity significantly. Through-movement waiting areas (TWAs) can be set at the symmetric intersection effectively, which can increase the capacity and short the cycle length furthermore. And the symmetric intersection is Channelized to improve the safety of TWAs. The Binary-Mixed-Integer-Linear-Programming (BMILP) model is employed to formulate the capacity maximization problem and signal cycle length minimization problem of the symmetric intersection. The BMILP model can be solved by standard branch-and-bound algorithms efficiently and outputs the lane allocation, signal timing decisions, and other decisions. Experiments analysis shows that the symmetric intersection with TWAs can increase the capacity and short the signal cycle length.     

Integrating mesoscopic dynamic traffic assignment with agent-based travel behavior models for cumulative land development impact analysis

A number of approaches have been developed to evaluate the impact of land development on transportation infrastructure. While traditional approaches are either limited to static modeling of traffic performance or lack a strong travel behavior foundation, today’s advanced computational technology makes it feasible to model an individual traveler’s response to land development. This study integrates dynamic traffic assignment (DTA) with a positive agent-based microsimulation travel behavior model for cumulative land development impact studies. The integrated model not only enhances the behavioral implementation of DTA, but also captures traffic dynamics. It provides an advanced yet practical approach to understanding the impact of a single or series of land development projects on an individual driver’s behavior, as well as the aggregated impacts on the demand pattern and time-dependent traffic conditions. A simulation-based optimization (SBO) approach is proposed for the calibration of the modeling system. The SBO calibration approach enhances the transferability of this integrated model to other study areas. Using a case study that focuses on the cumulative land development impact along a congested corridor in Maryland, various regional and local travel behavior changes are discussed to show the capability of this tool for behavior side estimations and the corresponding traffic impacts.     

船舶烧伤病房气流组织分析与优化

针对舰船舱室气流组织的形式特点,以烧伤病房作为研究对象建立数学模型,通过使用Airpak软件对烧伤病房不同设计方案下的气流组织进行了计算仿真,通过舱室温湿度,空气流速,热舒适指标等参数的对比,获得舱室的压力、温度、速度、热舒适性指标等的分布特性,对烧伤病房气流组织进行了分析并提出了优化方法,可以有效提高人员的舒适性和气流组织效果。     

组合型水泥粉煤灰碎石桩(CFG桩)复合地基在深厚软基处理中的应用

在深厚软土地基(fak≤100 kPa)上建造储罐等建筑物,承载力要求高、不均匀沉降变形要求严,若采用单一CFG桩复合地基加固,可能导致桩距过小或桩长太长,需要采用组合型复合地基,CFG桩+振冲碎石桩复合地基是组合型复合地基的一种。根据CFG桩+碎石桩组合型复合地基的加固机理,分析了其受力特性以及CFG桩和碎石桩的作用,研究表明CFG桩对提高地基承载力和减小沉降起控制作用。基于优化理论,建立了组合复合地基的优化设计方法。通过工程实例讨论了组合复合地基的优化设计方法,结果表明:复合地基的承载力、沉降量和经济效益均满足工程要求。     

基于NFFD 算法的船体几何变形技术

本文以非均匀有理B样条基函数作为参数体属性,并结合非均匀控制点网格,建立了适用于船体几何的NFFD变形技术。重点阐述了NFFD方法的基本原理和变形规则,并以矩阵表示方法为基础构建了数学模型。研究了控制点数量和分布对变形结果的影响,增加了控制点变形几何的能力并获得了更大的设计空间。最后,以某CNG运输船为例完成了球鼻艏、船艏和船艉部分几何的自动变形。本文的工作为船型优化提供了良好的变形工具。     

基于粒子群算法的水下多元线阵阵形有源校正方法

针对存在阵元位置误差的水下多元线阵,提出一种基于粒子群优化算法的远场有源阵形校正方法.该方法选用2个辅助源分时工作方式,利用无条件最大似然方位估计算法构建目标函数,并通过粒子群算法对阵元位置进行寻优.利用该方法对均匀线阵进行性能仿真实验.结果表明:该方法稳健性好、校正精度高,具有一定的应用前景.