Control system design for a pressure-tube-type supercritical water-cooled nuclear reactor via a higher order sliding mode method

Nuclear power plants exhibit non-linear and time-variable dynamics.Therefore,designing a control system that sets the reactor power and forces it to follow the desired load is complicated.A supercritical water reactor(SCWR)is a fourth-generation conceptual reactor.In an SCWR,the non-linear dynamics of the reactor require a controller capable of control-ling the nonlinearities.In this study,a pressure-tube-type SCWR was controlled during reactor power maneuvering with a higher order sliding mode,and the reactor outgoing steam temperature and pressure were controlled simultaneously.In an SCWR,the temperature,pressure,and power must be maintained at a setpoint(desired value)during power maneuvering.Reactor point kinetics equations with three groups of delayed neutrons were used in the simulation.Higher-order and classic sliding mode controllers were separately manufactured to control the plant and were compared with the PI controllers speci-fied in previous studies.The controlled parameters were reactor power,steam temperature,and pressure.Notably,for these parameters,the PI controller had certain instabilities in the presence of disturbances.The classic sliding mode controller had a higher accuracy and stability;however its main drawback was the chattering phenomenon.HOSMC was highly accurate and stable and had a small computational cost.In reality,it followed the desired values without oscillations and chattering.

Sliding Mode Predictive Control of Main Steam Pressure in Coal-fired Power Plant Boiler

Since the combustion system of coal-fired boiler in thermal power plant is characterized as time varying, strongly coupled, and nonlinear, it is hard to achieve a satisfactory performance by the conventional proportional integral derivative (PID) control scheme. For the characteristics of the main steam pressure in coal-fired power plant boiler, the sliding mode control system with Smith predictive structure is proposed to look for performance and robustness improvement. First, internal model control (IMC) and Smith predictor (SP) is used to deal with the time delay, and sliding mode controller (SMCr) is designed to overcome the model mismatch. Simulation results show the effectiveness of the proposed controller compared with conventional ones.

A Novel Coordinated Sliding Mode Controller Based on Lyapunov Method for SVC, Excitation and Steam Valving

A novel coordinated controller is proposed in the paper for SVC, excitation and steam valving for a single machine infinite system. Firstly, the nonlinear mathematic model of the system including the itation and steam valving is exactly linearized via state feedback. Then, the quasi-linearized system after the exact lineariztion is controlled by the sliding model controller based on Lyapunov direct method. At last, the novel coordinated controller is compared with a traditional linear controller and a nonlinear optimal controller respectively by simulations. The simulation results show that the proposed controller gives better dynamic response and stronger robustness.

Numerical analysis of 3-D sound propagation in lined ducts with circumferential mode sound sources at inlet

Numerical analysis of three-dimensional sound propagation in soft-soft or soft-hard circular ducts with circumferential and axial modes of sound sources at the inlet has been carried out. In this paper , the numerical method and the samples are offered and the effects of circumferential and axial modes on numerical results are discussed in detail .

Unsteady flow characteristic analysis of turbine based combined cycle(TBCC)inlet mode transition10.1016/j.jppr.2015.07.006

A turbine based combined cycle(TBCC)propulsion system uses a turbine-based engine to accelerate the vehicle from takeoff to the mode transition flight condition,at which point,the propulsion system performs a“mode transition”from the turbine to ramjet engine.Smooth inlet mode transition is accomplished when flow is diverted from one flowpath to the other,without experiencing unstart or buzz.The smooth inlet mode transition is a complex unsteady process and it is one of the enabling technologies for combined cycle engine to become a functional reality.In order to unveil the unsteady process of inlet mode transition,the research of over/under TBCC inlet mode transition was conducted through a numerical simulation.It shows that during the mode transition the terminal shock oscillates in the inlet.During the process of inlet mode transition mass flow rate and Mach number of turbojet flowpath reduce with oscillation.While in ramjet flowpath the flow field is non-uniform at the beginning of inlet mode transition.The speed of mode transition and the operation states of the turbojet and ramjet engines will affect the motion of terminal shock.The result obtained in present paper can help us realize the unsteady flow characteristic during the mode transition and provide some suggestions for TBCC inlet mode transition based on the smooth transition of thrust.

STEAM教育理念下的项目式教学模式建构研究

随着社会的进步和科学的快速发展,社会对于创新型人才和复合型人才的需求越来越多。为了培养出更多符合社会需要、促进社会发展的人才,本文基于STEAM教育理念对项目式教学模式进行研究,从项目式教学的过程出发,构建“项目策划-项目执行-项目反馈”的教学模式,培养学生的创新思维以及解决问题的能力,试图为项目式教学提供新思路。

基于STEAM教育理念的汽车保险课程5E教学模式研究

突出学生中心地位,以培养高阶能力为核心目标,将STEAM教育理念植入本土化课堂教学,并运用5E教学模式,通过分组讨论和实践探究相结合的方法,引导学生运用所学知识解决实际问题,不仅有助于实现知识的迁移应用,更能培养学生的创新精神、合作能力和实践能力。在课程实施过程中,教师充分发挥主导作用,结合线上教学资源,将课堂延伸至更广阔的领域,充分调动学生学习的主动性和参与度。同时,注重将思政元素融入课堂教学,使学生在学习知识的同时,真正实现全面发展。

STEAM教育理念下PFM混合教学模式在妇产科见习教学中的应用

目的:研究STEAM教育理念下PFM混合教学模式在妇产科见习教学中的应用效果。方法:将100名2020级临床医学专业的见习学生随机分为2组,分别通过STEAM教育理念下PFM混合教学模式(观察组)和传统的教学模式(对照组)接受临床见习教学。见习结束后,对2组学员的临床综合能力进行测评,另外用问卷调查的方法调查教学效果。结果:观察组学生在临床思维能力、学习兴趣以及与病人的沟通交流能力方面均显著优于对照组(P<0.01)。结论:STEAM教育理念下PFM混合教学模式在妇产科见习教学中切实可行,具有良好的教学效果。

STEAM教育理念下的项目式教学模式探索与实践——以高职“物联网应用开发”课程为例

文章以“物联网应用开发”课程为例,深入剖析STEAM教育理念在传统教学过程中所面临的挑战与问题。针对这些问题,创新性地提出将STEAM教育理念与项目式教学法相结合的教学模式。该模式围绕教学目标、教学过程、教学评价以及教学保障这四个核心维度进行了全面设计,并从课前筹备、科学探索、工程实现、艺术融入、课后巩固这五个教学步骤展开教学实践。通过对比发现,该教学模式在提升学生的跨学科整合能力、实践与创新能力、学习兴趣与动力、团队合作与沟通能力以及促进学生全面发展等方面均具有积极作用。

STEAM教育中以计算思维培养为核心的6E设计型学习模式探究

计算思维是运用数学方法来解决问题,进而认识和改造世界的一项关键技能;STEAM的教学思想强调情境性、跨学科性和综合性,其目的是从科学、技术、工程、艺术、数学等多个方面去解决问题。因此,计算思想和STEAM的思想是相辅相成的。文中将“绘制五星红旗”作为例子,运用6E设计型学习模式展开了课程设计,让学生运用科学、技术、数学等多学科知识,通过定义问题、分析问题、抽象问题、设计算法、评估迁移等过程来解决问题,进而对STEAM理念下如何利用编程来培养计算思维进行了探索。

基于STEAM理论的智慧课堂教学模式研究与设计

智慧课堂教学是顺应教育信息化的热点产物,也是智慧教育落实到课堂的有力依据,对未来智慧教育融入校园十分有意义。STEAM理论强调的跨学科思维,为未来智慧课堂发展提供了新方向。本研究从分析STEAM理念与智慧课堂的内在联系出发,通过查阅文献以及结合调研,分析了基于STEAM理论的智慧课堂教学现状。最后,从情境与问题、探究与数学、工程与制作、创意与扩展以及评价与反思五个环节构建出基于STEAM理论的智慧课堂教学模式,并针对七年级信息技术3D打印内容“制作水杯”进行了教学设计,旨在教学过程中有机融合STEAM理论与智慧课堂技术,最终提高智慧课堂教学效率。

基于STEAM教学理念的生理学课程BOPPPS教学模式探索

目的探讨基于STEAM教学理念的生理学课程BOPPPS教学模式的应用效果。方法选取2022年3—7月信阳职业技术学院的临床专业学生92名作为对照组,选取2023年3月—2023年7月本学院临床专业学生89名作为观察组。对照组按照传统线上线下教学模式进行生理学课程教学,观察组按照基于STEAM教学理念的融合BOPPPS教学模式进行生理课程教学,学期结束后,对比两组生理机能实验情况、理论考核成绩、生理机能实验考核成绩、自主学习性、并调查学生对教学形式的满意度。结果观察组生理机能实验成功率较对照组高,实验耗时较对照组短,差异有统计学意义(P<0.05);观察组理论考核成绩、生理实验操作考核成绩均优于对照组,差异有统计学意义(P<0.05);观察组课后作业完成率、线上学习次数均高于对照组,差异有统计学意义(P<0.05);观察组教师教学满意度和实践课程教学满意度得分均较对照组高,差异有统计学意义(P<0.05)。结论基于STEAM教学理念的生理学课程BOPPPS教学模式可以促进自主学习,有效提高教学质量和教学满意度。

高温中压长输蒸汽管道的热补偿方式及支架约束

高温中压长输蒸汽管道热补偿方式有别于电厂内部短距离输送管道,既要考虑安全性,又要考虑项目的经济性。论文对比常用热补偿方式的优缺点,提出高温中压长输蒸汽管道采用旋转补偿器补偿为主、自然补偿为辅的热补偿方式较为合理。对直线线路段、平行线路段、转角及转角叠加标高微调段、直线高差段、直线跨越段这几种常见的管道布置形式,通过START应力计算软件建模分析,确定较优的热补偿方式及支架约束条件。

高职STEAM教育的内涵、模式及实施路径

21世纪培养运用STEAM跨学科知识进行科学探究与真实问题解决能力的复合型、创新型人才是高职院校教学改革的重点。研究从STEAM教育的兴起、内涵及理论依据入手,剖析了高职STEAM教育的应用模式,提出了高职STEAM教育的实施路径。

基于VMD-XGBoost模型及因果特征选取的汽轮发电机组振动信号预测技术研究

“双碳”目标下,我国能源格局产生深刻变化,对汽轮机发电机安全稳定运行的要求进一步提高,深入挖掘分析海量运行数据有助于机组运行状态的评估及预测。提出构建汽轮发电机组参数因果关系网络探究参数间的因果关系,利用VMD算法分解振动信号并搭建XGBoost预测模型对各信号分量进行预测,叠加各信号分量的预测值以得到振动信号的预测结果。利用国内某1000MW汽轮发电机组运行数据对所提模型进行论证实验,结果表明本文所提模型有较高预测精度。

STEAM理念导向的图书情报专业硕士案例教学模式

为实现图书情报专业硕士教学中知识与能力目标,解决图书情报专业硕士教学中存在的跨学科教学难题,文章在分析图书情报专业硕士教学特征的基础上,构建出STEAM理念导向的图书情报专业硕士案例教学模式,并基于该模式进行图书情报专业硕士案例教学的系统动力学仿真分析。该模式将图书情报专业硕士案例教学中的教学流程、教学主体的任务、知识与能力的建构以及跨学科教学的实现方法有机结合在一起,为其教学提供理论基础。系统动力学仿真结果显示:提升图书情报专业硕士案例教学的实施效果首先应该加大对学生的投入,其次注重学科融合、师生平等、轻松教学环境的形成。

基于STEAM教育理念构建高等职业教育人才培养模式

STEAM教育以跨学科、多元化协作式学习方式而被教育界广为关注和认可。探索构建一种基于STEAM教育理念面向高等职业教育的“1平台2核心4融合1保障”的人才培养模式,以培养高素质复合型技术技能人才为目标,让学生运用多学科知识解决实际问题,形成高阶的思维能力和高品质的综合素质,不断提升职业能力,增强核心竞争力。教学实践表明,该人才培养模式在教学满意度、1+X证书试点、竞赛获奖、目标达成度和专业办学成效等方面取得了较好的效果。

Optimal Dispatch and Pricing of Industrial Parks Considering CHP Mode Switching and Demand Response

Industrial parks(IPs)play a crucial role in facilitating economic efficiency and comprehensive energy utilization in the industrial age.At the same time,multi-energy coupling and management of various types of energy in IP have become serious challenges.In this paper,combined heat and power unit(CHP)model considering operation mode switching characteristics is formulated by exploring its internal composition to improve output flexibility of the energy supply side.Then,heat and electricity integrated energy system(HE-IES)optimal dispatch and pricing model are established,taking electricity and heat demand response strategy and steam thermal inertia property into account.Based on the above models,a mixed-integer bilinear programming framework is designed to coordinate the day-ahead operation and pricing strategy of the HE-IES in the IP.The scenario study is carried out on a practical industrial park in Southern China.Numerical results indicate the proposed mechanism can effectively improve IP’s energy utilization and economic efficiency.

Back Pressure Characteristics for Turbine Channel of External-Parallel TBCC Inlet

For investigating the back pressure characteristics of turbine channel of an external-parallel turbine-based combined cycle(TBCC)inlet during the mode transition with the freestream air Mach number of 1.8,wind tunnel tests and numerical simulations are carried out.The results show that the critical back pressure of the turbine channel decreases linearly with the decrease of the open degree of splitter plate.The turbine channel has self-starting capacity when the open degree of the turbine channel is 100%.The total pressure recovery coefficient increases with the increase of back pressure when turbine channel is at supercritical and critical state.The mass capture ratio,total pressure recovery coefficient and outlet pressure ratio decrease obviously when turbine channel is at subcritical state.Results of the research would provide scheme reference and technology storage for TBCC propulsion evolution.

六高调门配置汽轮机进汽工况优化研究

针对亚临界300 MW汽轮机组进行建模与模态分析,可以得到汽轮机转子前两阶的固有频率与临界转速。对六高调门配置汽轮机的主要进汽工况进行说明并分析计算轴向气流力,利用Matlab软件对转子所受轴向力进行频谱分析,比较转子基频与固有频率,得到不同进汽工况下冲击力主频对各阶临界转速的避开率。研究结果表明:汽轮机转子在全周进汽工况下的稳定性与安全性最高,但流动损失较大,双对角进汽模式是最佳进汽模式。