两种风荷载模拟方法下的邮轮系泊撞击能量试验研究

以22.5万t邮轮为例,分别进行单风、单浪和风浪共同作用下的系泊撞击能量试验,研究在风机法和挂重法两种不同的风荷载模拟方法下单风、单浪和风浪共同作用时对邮轮撞击能量的影响。试验结果表明:在风浪共同作用时,运用风机法时的系泊撞击能量比挂重法的大17.4﹪;另外,风浪共同作用时,风荷载对邮轮系泊撞击能量的影响较大,风浪共同作用时的撞击能量远大于单浪作用时的撞击能量。

风光互补路灯系统的优化设计方法

采用风机优先法,对风光互补路灯系统的优化设计方法进行了分析。首先根据负载需求初步选定风机容量;其次计算出与选定风机相匹配的太阳能电池板的容量;进而计算每一组设备组合的总价值;最后选定总投资价格最小的风光互补发电组合。文章结合道路照明的实例,给出了风光互补路灯系统在负载需求和经济方面的优化设计。

变风量空调系统控制方法对比研究

介绍了变风量空调系统的四种控制方法的控制原理、特点及其优缺点。定静压控制简单,但节能效果差;变静压控制方法与定静压控制方法相比,节能效果明显,但增加了阀开度控制,使控制更加复杂,风阀开度信号的反馈对风机转速的调节有一个滞后的过程。直接数字控制法通过末端装置的风阀全开时的开度—压差—流量特性,风管的流量—阻力特性,风机的转速—扬程—流量特性,满足最小静压控制的送风机转速。风机总风量控制法的基本原理是根据风机相似律,在空调系统阻力系数不发生变化时,总风量和风机转速是一个正比关系,并使用误差理论中的均方差,来消除相对风量的不一致。

风电场理论功率计算方法的分析与讨论

近年来新疆电网风电装机快速增长,受网架、调峰等因素制约,部分时段存在风电出力受阻的情况,风电场弃风时段的理论发电量减去该时段的实际发电量即为弃风电量,为准确计算风电场弃风时段的电量损失,介绍了风电场理论功率计算方法,并对新疆西北部某风电场应用样板风机法、测风数据外推法进行了分析讨论,计算结果表明规则矩阵式排列风电场,采用样板风机法推测理论功率更加精确,计算的理论电量更接近实际,从而间接的对弃风电量的统计分析有很大的促进。

变风量空调系统的几种控制方法

本文介绍了变风量空调系统的三种控制方法的控制原理、特点及其优缺点。

变风量系统最小新风量控制方法的比较

变风量系统作为一项比较成熟的技术，在国外建筑中已经普遍采用。近年来，随着国内建筑业的高速发展，变风量系统在国内的空调设计中已开始大量应用，并以其良好的节能性及布置上的灵活性而得到空调设计者们的认可。但是，空调变风量系统中新风量的控制问题也越来越受到人们的关注。

变风量空调系统的几种控制方法

本文介绍了变风量空调系统的三种控制方法的控制原理、特点及其优缺点。

地下车库通风的变频控制研究

针对目前地下车库变风量系统中常用的间歇控制法和双速风机法存在的控制过于简单、不能很好地改善地下车库内的空气品质、不能最大限度地节能的问题,提出了根据车库内CO浓度的实时变化情况,采用风机变频控制地下车库通风量的方法。介绍了某地下车库通风系统的风机变频控制改造工程。结果表明,风机变频控制改造在技术上是可行的,能节约电能,且投资回收期较短。

寒区水工结构新型防冰冻技术研究

冰冻破坏是寒区水工结构常见的病害,影响水工结构的正常运行和耐久性。目前常用的防冰冻技术如压力水射流法和压力空气吹泡法等存在设备成本高、运行能耗大的缺点。为解决以上问题,在综合分析各种防冰冻技术优缺点的基础上,首次提出了风机吹泡法防冰冻技术,即在现有压缩空气吹泡法的基础上,使用大风量、低能耗的离心式风机取代传统的低风量、高能耗的空气压缩机。工程实践表明:该技术实现了防冰冻装置的低能耗运行,能耗降至现有技术的1/10,同时大幅度降低了防冰冻装置制造成本,造价约为压力水射流法的1/3、压缩空气吹泡法的1/10。基于风机吹泡法防冰冻技术,应用模块化设计理念,研制出适合寒区水工结构防冰冻装置,通过一系列室内试验和现场试验,实现了防冰冻装置低成本、低能耗、绿色化和自动化的技术目标。

变风量空调系统的新风问题

介绍了变风量空调系统的特点及设计者应注意的问题 ,并着重介绍了控制变风量空调系统最小新风量的方法。

建筑外围护结构整体气密性能检测关键技术

建筑外围护结构整体气密性能是低能耗建筑的一项重要技术指标,但是我国尚未建立相关的测试标准和测试方法。在国外建筑外围护结构整体气密性能检测标准的基础上,通过大量工程测试应用实践,结合我国建筑发展特点和科学技术水平,研究提出我国建筑外围护结构整体气密性能检测中关键问题的解决方法,提高相关测试方法和测试数据的科学性与真实性,为今后我国建筑外围护结构整体气密性检测标准的编制和测试方法的应用提供参考和借鉴。

变风量空调系统的控制方案设计分析

本文介绍了变风量空调系统中的定静压控制方法、变静压控制法、直接数字控制法(DDC)、风机总风量控制法的原理及优/缺点。

Investigation on Installation of Offshore Wind Turbines

Wind power has made rapid progress and should gain significance as an energy resource,given growing interest in renewable energy and clean energy.Offshore wind energy resources have attracted significant attention,as,compared with land-based wind energy resources,offshore wind energy resources are more promising candidates for development.Sea winds are generally stronger and more reliable and with improvements in technology,the sea has become a hot spot for new designs and installation methods for wind turbines.In the present paper,based on experience building offshore wind farms,recommended foundation styles have been examined.Furthermore,wave effects have been investigated.The split installation and overall installation have been illustrated.Methods appropriate when installing a small number of turbines as well as those useful when installing large numbers of turbines were analyzed.This investigation of installation methods for wind turbines should provide practical technical guidance for their installation.

On Advanced Control Methods toward Power Capture and Load Mitigation in Wind Turbines

This article provides a survey of recently emerged methods for wind turbine control. Multivariate control approaches to the optimization of power capture and the reduction of loads in components under time-varying turbulent wind fields have been under extensive investigation in recent years. We divide the related research activities into three categories： modeling and dynamics of wind turbines, active control of wind turbines, and passive control of wind turbines. Regarding turbine dynamics, we discuss the physical fundamentals and present the aeroelastic analysis tools. Regarding active control, we review pitch control, torque control, and yaw control strategies encompassing mathematical formulations as well as their applications toward different objectives. Our survey mostly focuses on blade pitch control, which is considered one of the key elements in facilitating load reduction while maintaining power capture performance. Regarding passive control, we review techniques such as tuned mass dampers, smart rotors, and microtabs. Possible future directions are suggested.

Design of Wind Turbine Torque Controller with Second‑Order Integral Sliding Mode Based on VGWO Algorithm

A robust control strategy using the second-order integral sliding mode control(SOISMC)based on the variable speed grey wolf optimization(VGWO)is proposed.The aim is to maximize the wind power extraction of wind turbine.Firstly,according to the uncertainty model of wind turbine,a SOISMC torque controller with fast convergence speed,strong robustness and effective chattering reduction is designed,which ensures that the torque controller can effectively track the reference speed.Secondly,given the strong local search ability of the grey wolf optimization(GWO)and the fast convergence speed and strong global search ability of the particle swarm optimization(PSO),the speed component of PSO is introduced into GWO,and VGWO with fast convergence speed,high solution accuracy and strong global search ability is used to optimize the parameters of wind turbine torque controller.Finally,the simulation is implemented based on Simulink/SimPowerSystem.The results demonstrate the effectiveness of the proposed strategy under both external disturbance and model uncertainty.

Approximate Solution for Mechanism of Thermally and Wind-driven Ocean Circulation

The thermally and wind-driven ocean circulation is a complicated natural phenomenon in the atmospheric physics. Hence we need to reduce it using basic models and solve the models using approximate methods. A non-linear model of the thermally and wind-driven ocean circulation is used in this paper. The results show that the zero solution of the linear equation is a stable focus point, which is the path curve trend origin point as time (t) trend to infinity. By using the homotopic mapping perturbation method, the exact solution of the model is obtained. The homotopic mapping perturbation method is an analytic solving method, so the obtained solution can be used for analytic operating sequentially. And then we can also obtain the diversified qualitative and quantitative behaviors for corresponding physical quantities.

变风量空调系统的前沿技术

分析和讨论了变风量空调系统主要的前沿技术,包括变风量末端装置的改进,变风量空调系统的投票法变送风温度设定和变静压控制、总风量控制、最小阻力控制等风机转速控制方法,以及全新风变风量空调系统的设计。

Smoke movement in a tunnel of a running metro train on fire

Research on the distribution of smoke in tunnels is significant for the fire emergency rescue after an operating metro train catches fire. A dynamic grid technique was adopted to research the law of smoke flow diffusion inside the tunnel when the bottom of a metro train was on fire and to compare the effect of longitudinal ventilation modes on the smoke motion when the burning train stopped. Research results show that the slipstream curves around the train obtained by numerical simulation are consistent with experimental data. When the train decelerates, the smoke flow first extends to the tail of the train. With the decrease of the train's speed, the smoke flow diffuses to the head of the train. After the train stops, the slipstream around the train formed in the process of train operation plays a leading role in the smoke diffusion in the tunnel. The smoke flow quickly diffuses to the domain in front of the train. After forward mechanical ventilation is provided, the smoke flow inside the tunnel continues to diffuse downstream. When reverse mechanical ventilation operates, the smoke in front of the train flows back rapidly and diffuses to the rear of the train.

Influence of a Deflector or a Wall on Savonius Rotor Efficiency

The Savonius rotor is a vertical axis-wind machine composed of two half cylindrical blades presenting a central gap. It is a slow velocity machine compared with horizontal wind machines. Its efficiency is about twenty per cent. In this work experimental tests are presented using two kind of deflectors placed in front of the resistive blade. Such disposition allows to hide the resistant blade and to guide the flow toward the motrice blade. Two deflectors have been used： a short one and a long one. The results obtained in wind tunnel have shown that the long deflector is the more efficient, essentially for high values of the tip speed ratio. One has been interested, using a numerical approach, in the study of the influence of a wall on the aerodynamical field near the rotor.

Forecasting of wind velocity:An improved SVM algorithm combined with simulated annealing

Accurate forecasting of wind velocity can improve the economic dispatch and safe operation of the power system. Support vector machine (SVM) has been proved to be an efficient approach for forecasting. According to the analysis with support vector machine method, the drawback of determining the parameters only by experts' experience should be improved. After a detailed description of the methodology of SVM and simulated annealing, an improved algorithm was proposed for the automatic optimization of parameters using SVM method. An example has proved that the proposed method can efficiently select the parameters of the SVM method. And by optimizing the parameters, the forecasting accuracy of the max wind velocity increases by 34.45%, which indicates that the new SASVM model improves the forecasting accuracy.