计及灵活性提升的热电厂日前市场竞价策略

针对含多类型燃煤热电机组与多种电热解耦设备的热电厂在电力现货市场中的报价决策问题,提出了基于价格接受者角色的热-电分步决策竞价模型。首先,依据次日预测价格进行热电厂日前最优产量决策,确定厂内电热解耦设备的运行计划。然后,根据机组调节能力,计算热电厂在次日各时段的发电功率范围;进而,构建分段阶梯形报价曲线。最后,以中国北方地区某典型燃煤热电厂为例,基于现货市场试点的3种典型场景出清电价,验证了所提热-电分步竞价决策模型的有效性;同时分析结果表明,日前市场难以为燃煤热电厂灵活性提升改造提供足够的经济激励。     

叶片旋流管内核心流强化传热分析与结构优化

管内湍流强化传热方法一般是增加壁面换热面积,但这会显著提高管内流动阻力。本文根据管内核心流强化传热的原理,提出了一种高效低阻的叶片旋流管,分析其传热强化的机理,建立相应的物理和数学模型。数值分析的结果表明,在圆管内置若干组旋流叶片后,可显著强化管内湍流换热,且流动阻力的增幅低于换热强化的增幅;当常温水流过管长为960 mm,管径为20 mm的圆管,且在管内核心流区域设置4组4叶片旋流单元时,其性能评价系数SPEC在Re数为3 000~15 000的范围内均超过1.5,最高可达1.9左右。     

数值研究大屏对四角切向燃烧煤粉锅炉炉内流动与燃烧过程的影响

为分析大屏对炉内流动、传热与燃烧过程的影响,该文对有、无大屏的工况进行了对比计算,结果表明,大屏削弱了炉内上部旋流,并使大屏后方出现“气流短路”现象,使局部流量增加,流速加大,局部换热加强,大屏的存在对四角切向燃烧煤粉锅炉的局部超温爆管现象有直接的影响。图６ 表２ 参５     

Heat transfer in annular channels with flow swirling

We present results from an analysis of experimental data on heat transfer in channels with one- and two-sided heating and with flow swirling by means of screw-type inserts or by winding a thin-walled capillary with a thickness equal to the annular gap. We also propose generalizing relations for calculating heat transfer in annular channels with flow swirling and with different operating and design parameters.     

Study of heat transfer on concave and convex surfaces of an annular channel with flow swirling

Results of experimental studies of postcrisis heat transfer in annular steam-generating channels are presented. It is recognized that, in annular channels with flow swirling, the value of the vapor quality at which deteriorated postcrisis heat transfer takes place and the intensity of heat transfer on convex and concave surfaces are different. Correlations for determination of heat transfer coefficients on these surfaces in the annular channel with flow swirling are presented.     

Evaluation of the thermal efficiency of a high-temperature heat-insulation structure based on honeycomb plastic

Highly efficient heat-insulation materials are needed in order to reduce the heat losses in operation of heat-power equipment at temperatures up to 700°C. A review of the available solutions showed that the development of a high-temperature heat-insulation structure of a new type is needed. The basic features of application of honeycomb plastics in heat insulation of heat-power equipment are discussed, the known techniques for evaluating the heat conductance of such materials are reviewed, and the results of calculation–parametric studies on determining the optimum honeycomb design for heat-insulation structures are reported.     

内螺旋外棘齿管对流换热与流阻实验研究

针对火力发电厂无铜化运行需求．研制并加工出一种钢质双侧强化传热管一内螺旋外棘齿管。采用通用的强化传热管试验装置,对5根不同结构参数的内螺旋外棘齿管进行了水平单管管外蒸汽冷凝和流阻特性试验研究。根据大量实验数据,拟合出实验雷诺数尺P范围内的管内换热努塞尔数Nu及阻力系数f的计算关联式,并对内螺旋外棘齿管的热力性能进行了评价。实验研究发现：所有内螺旋外棘齿管管内换热系数比光滑管提高了42％～152％,同时阻力系数增加了48％～350%。最后得出结论：无论在何种工况下运行。内螺旋外棘齿管的换热与流阻综合性能均优于光滑管。可用做发电厂换热设备的管芯。大大提高电厂热能的利用。     

Refrigeration generation using expander-generator units

The problems of using the expander–generator unit (EGU) to generate refrigeration, along with electricity were considered. It is shown that, on the level of the temperatures of refrigeration flows using the EGU, one can provide the refrigeration supply of the different consumers: ventilation and air conditioning plants and industrial refrigerators and freezers. The analysis of influence of process parameters on the cooling power of the EGU, which depends on the parameters of the gas expansion process in the expander and temperatures of cooled environment, was carried out. The schematic diagram of refrigeration generation plant based on EGU is presented. The features and advantages of EGU to generate refrigeration compared with thermotransformer of steam compressive and absorption types were shown, namely: there is no need to use the energy generated by burning fuel to operate the EGU; beneficial use of the heat delivered to gas from the flow being cooled in equipment operating on gas; energy production along with refrigeration generation, which makes it possible to create, using EGU, the trigeneration plants without using the energy power equipment. It is shown that the level of the temperatures of refrigeration flows, which can be obtained by using the EGU on existing technological decompression stations of the transported gas, allows providing the refrigeration supply of various consumers. The information that the refrigeration capacity of an expander–generator unit not only depends on the parameters of the process of expansion of gas flowing in the expander (flow rate, temperatures and pressures at the inlet and outlet) but it is also determined by the temperature needed for a consumer and the initial temperature of the flow of the refrigeration–carrier being cooled. The conclusion was made that the expander–generator units can be used to create trigeneration plants both at major power plants and at small energy.     

Efficiency of Water Purification from Dissolved Gases under Weak and Strong Phase Interaction in Film Degassers

Water purification processes in film decarbonizers and thermal deaerators with different contact arrangements in the modes of weak and strong interaction between phases are considered. Weak interaction is characterized by a separate movement of phases, wherein a gas or vapor flow hardly affects the hydrodynamics of a liquid film. Such a mode is most often implemented in the case of countercurrent phases. At a gas or vapor velocity greater than 8 m/s and an atmospheric pressure, the gas flow carries the liquid film in an ascending or descending flow. In this mode, mass and heat transfer processes are greatly intensified. The modes are considered by the example of removal of aggressive corrosive gases at TPPs and industrial enterprises. Expressions are given for the calculation of the mass exchange characteristics of degassers and for the efficiency of water purification from oxygen and carbon dioxide. It is shown that a strong interaction occurs in the tubes with discrete-rough walls and a ribbon swirler, whereas a weak one takes place in irregular (chaotic) packed beds and regular corrugated packed beds with a rough surface. To calculate the efficiency of mass transfer (the extraction of dissolved gases from water), we used such flow structure models as a diffusion model and a cell model with bulk mass sources. Expressions for the calculation of model parameters—dispersion coefficients, number of cells, mass transfer coefficients in the liquid phase—are presented. The results of calculations of the mass transfer efficiency in packed columns and channels with discrete-rough walls and swirling flows are given. An example for mounting a packed bed in a DSA-300 deaerator is presented. Conclusions are drawn concerning the most rational designs and operating modes of thermal deaerators and decarbonizers.     

An algorithm for combined heat and power economic dispatch

This paper presents a new algorithm for combined heat and power (CHP) economic dispatch. The CHP economic dispatch problem is decomposed into two sub-problems: the heat dispatch; and the power dispatch. The sub-problems are connected through the heat-power feasible region constraints of cogeneration units. The connection can be interpreted by the unit heat-power feasible region constraint multipliers in the Lagrangian function, and the interpretation naturally leads to the development of a two-layer algorithm. The outer layer uses the Lagrangian relaxation technique to solve the power dispatch iteratively. In each iteration, the inner layer solves the heat dispatch with the unit heat capacities passed by the outer layer. The binding constraints of the heat dispatch are fed back to the outer layer to move the CHP economic dispatch towards a global optimal solution     

湖南省小火电降低煤耗的途径

分析了湖南省地方小大电煤耗高的主要原因,并提出解决途径。加快热电联产步伐、采用循环流化床、型煤技术、进行锅炉技术改造     

安全约束最优潮流的实用模型及故障态约束缩减方法

针对大型电力系统安全约束最优潮流(SCOPF)问题具有的计算规模庞大、求解困难的特点,提出了基于潮流转移关系的SCOPF实用模型及故障态约束缩减方法。首先通过预想故障分析建立故障前后的有功潮流转移关系,将故障态支路有功潮流描述为基态支路有功潮流的函数,从而将故障态支路有功潮流约束描述为基态支路有功潮流的线性不等式约束;然后通过对并联线路或并列主变压器进行分组,利用组内支路的有功潮流分布关系减少需监视的支路规模;最后利用设备短时通流能力明显大于其长期通流能力的特征对故障态支路潮流约束进行过滤,以尽可能减小SCOPF问题的计算规模。IEEE 14节点测试系统和华东电网的仿真分析验证了所提模型及约束缩减方法的正确性和有效性。     

旋流排沙渠道体型优化的正交数值试验方法和应用

为优化多泥沙河流引水渠道内的泥沙级配,实现泥沙分选的效果,提出了一种新型旋流排沙渠道。基于数值模拟与模型试验结果,采用正交数值试验方法,以分流比与排沙洞典型断面的流速为目标函数,优化了旋流排沙渠道的关键体型参数,对比分析了体型优化前后旋流排沙渠道的水沙特性。结果表明,正交数值试验设计能有效提升结构的优化效率,获得具有良好性能的旋流排沙渠道。当渠道来流量为30 L·s^-1时,优化体型的排沙耗水量较原体型减小21.5%,分流比减小4.6%,排沙洞出口断面最大流速增大10.8%,水流的挟沙能力增强,在排沙洞内形成更有利于泥沙运动的旋转水流条件;体型优化前后的旋流排沙渠道对粒径为0.075～3.0 mm泥沙的总体截沙率分别高达90%和88%,表明旋流排沙渠道具有良好的排沙特性,且优化体型排沙洞内的泥沙淤积量较原体型减小61.8%。本成果可为这种新型旋流排沙渠道体型优化和其在引水渠道等工程中的应用提供参考。     

一种新型结构的热管式散热冷板性能的数值模拟试验与分析

针对高热流密度负荷下大功率行波管的散热冷却，该文在试验研究的基础上，对一种具有并联热管组结构的新型平板式热管散热冷板的内部运行机理进行了数值模拟，分析并预测了加热冷却条件对该平板式热管运行性能的影响，为该新型平板式热管散热冷板的实际应用提供了依据。     

多能源网络稳态能量流分析与计算方法

适用于不同能源形式通用的数学描述和统一的能量流计算方法是多能源网络规划运行的理论基础.文中在构建多能源网络三维拓扑结构图的基础上,提出能量传递的统一描述,借用热力学中强度量和广延量的概念构建多能源网络中支路的能量传递方程.以最常见的圆柱形传递管道为例,推导交直流电能传递、不可压缩黏性流体、可压缩气体,以及热传导、流体传热的支路能量传递过程,并建立描述节点广延量守恒的网络方程.通过采用牛顿-拉夫逊法分别对独立能源子网和多能源网络的稳态能量流进行求解,算例验证了所提方法及模型的可行性.     

Methods for investigating the thermal and hydraulic characteristics and structure of swirl flows

The well-known methods for investigating single- and two-phase flows in channels with swirling are analyzed. Some results obtained from an investigation into the structure of two-phase flow in annular channels with flow swirling are presented.     

计及换热器传热特性的热电联合系统优化调度

换热器传热特性是影响热电联合系统优化调度的关键因素之一。针对热电联合系统,基于传热原理,采用抽汽的三级传热模型来描述换热器的传热过程,利用迭代法计算一定热负荷下的抽汽量,提出计及换热器传热特性的热电、火电、风电的联合调度模型。最后以最小化煤耗量为优化目标,分析换热器传热特性对抽汽传热过程和热电联合系统调度结果的影响。算例表明：增大换热器传热面积、降低换热器出口水温可以不同程度地提高风电消纳能力,降低运行成本,研究结果为电热联合系统优化调度方案提供换热参数选择的依据。     

计及换热器传热特性的热电联合系统优化调度

换热器传热特性是影响热电联合系统优化调度的关键因素之一。针对热电联合系统,基于传热原理,采用抽汽的三级传热模型来描述换热器的传热过程,利用迭代法计算一定热负荷下的抽汽量,提出计及换热器传热特性的热电、火电、风电的联合调度模型。最后以最小化煤耗量为优化目标,分析换热器传热特性对抽汽传热过程和热电联合系统调度结果的影响。算例表明：增大换热器传热面积、降低换热器出口水温可以不同程度地提高风电消纳能力,降低运行成本,研究结果为电热联合系统优化调度方案提供换热参数选择的依据。     

A study of heat-transfer processes in a countercurrent cyclone heat exchanger

Heat-transfer processes in a countercurrent cyclone heat exchanger are investigated on a pilot installation. Volumetric coefficients of heat transfer from gases to a flow of solid particles are determined during operation with tangentially swirled flow of gas suspension, separation of solid particles on the heat-exchanger walls, and deceleration of flue gas flows as they collide with the charge mixture fed to the apparatus.     

Flow-Accelerated Corrosion Wear of Power-Generating Equipment: Investigations,Prediction, and Prevention: 1. Flow-Accelerated Corrosion Processes and Regularities

The first part of this review considers the prerequisites and scales of damage inflicted to the equipment and pipelines of power plant units as a consequence of flow-accelerated corrosion, and examples of accidents involving lethal outcomes that occurred at nuclear power plants as a result of pipeline ruptures caused by flow-accelerated corrosion are given. It is shown that the scope of items susceptible to flow-accelerated corrosion includes components of condensate–feedwater and wet steam path equipment and pipelines made of carbon and low-alloy steels. The main negative consequences caused by flow-accelerated corrosion are local metal thinning spots that can lead to abrupt failures and depressurization of the process circuit and contamination of working fluid with iron containing products of flow-accelerated corrosion. Sedimentation of these products in a steam generator is one of factors causing damage to and failure of its heat transfer tubes. It is proposed to draw a distinction between general and local flow-accelerated corrosion. General flow-accelerated corrosion causes ingress of iron-containing compounds into the working fluid and is characterized by a moderate metal thinning rate that does not lead to destructions or occurrence of wormholes involving loss of process circuit leak tightness. The effects of local flow-accelerated corrosion manifest themselves in small parts of intricately shaped channels and are characterized by a significant metal thinning rate with possible occurrence of wormholes or abrupt destruction of the pipeline and power-generating equipment components. Typical cases of and statistical data on damages inflicted to nuclear power plant components due to flow-accelerated corrosion are presented. The physicochemical fundamentals and regularities relating to flow-accelerated corrosion of metal occurring in one- and two-phase flows are considered. It is pointed out that the hydrodynamic factor plays the determining role in the occurrence of zones and rate of local thinning caused by flow-accelerated corrosion. The key hydrodynamic characteristics influencing the local flow-accelerated corrosion rate are determined. Fundamental differences between the mechanisms governing flow-accelerated corrosion in two-phase medium and single-phase water flow are shown. These differences stem from the specific features of hydrodynamics pertinent to the motion of liquid film and interphase redistribution of admixtures and gases that gives rise to a change in the pH value of liquid. The results from experiments aimed at studying the effect of temperature on the flow-accelerated corrosion rate of different metals in a two-phase wet steam flow and the effect of steam wetness degree on the liquid film flow mode are presented.