贾汪PFBC中试电站烟气旁路减温减压装置研究设计及应用

贾汪PFBC-CC燃煤联合循环发电中试电站的烟气旁路系统是机组启动或烟气轮机甩负荷和发生故障时高温高压烟气的安全通道,旁路中的减温减压装置是其关键设备。文章对旁路烟道的减温减压装置进行了专门设计,采用新颖的高速文丘里雾化冷却器和小孔节流降压消音器相结合的方法,实现了不同工况下高温高压含尘烟气的减温减压排放。中试电站调试运行结果证明该减温减压装置系统结构紧凑,运行可靠,经济合理。     

垃圾焚烧电站旁路减温减压装置分析及计算

介绍了垃圾焚烧电厂的旁路系统,并对两级多孔节流式、环形逐级膨胀式两种结构形式的旁路末级减温减压装置进行了技术总结,给出了旁路末级减温减压装置的焓熵工作原理图及计算公式,分析了各自的结构特点。最后结合工程实例计算阐述了两种装置的异同点,并对垃圾焚烧电厂旁路末级减温减压装置类型的选择给出了建议。该分析计算结果为后续垃圾焚烧发电项目旁路消能装置的设计选型提供了参考。     

基于等效热降法的引射汇流装置节能效果分析

为实现热能按质利用,采用引射汇流装置实现再热冷段与五段抽汽联合供汽,替代原有从再热热段减温减压后的对外供汽方式;采用等效热降法对某330MW热电联产机组进行了计算,结果表明,机组负荷在250MW以上时,采用引射汇流装置节能效果明显。     

基于BP神经网络的蒸汽减温减压器流量计算方法研究

在工业供汽系统改造过程中,为了更好的提高控制质量,需要快速、准确预测计算出减温减压器蒸汽流量,其值受多参数影响是预测计算的难点之一.通过对蒸汽减温减压器的特性分析,指出蒸汽减温减压器流量特性方程具有较强的非线性,利用BP网络非线性映射特性,采用BP网络建立了蒸汽减温减压器流量特性方程,利用某330MW火电机组减温减压系...     

减温减压器变工况运行分析

本文从汽轮机组的起运行着手，结合单元制机组的运行特点及滑参数起停方式，对旁路三级减温减压器的实际工作情况进行了分析探讨，对我厂已投运机组的减温减压器进行了分析解剖，在给定入口蒸汽条件的基础上，推算出了相应的变工况流量与入口压力之间的特性曲线，可作为相应型号减温减压的特性曲线，供实际变工况运行参考，本文中所推荐时的计算公式亦可作为减温减压器变工况计算的计算公式，通过对三级减温减压器的变工况分析，对我     

贾汪PFBC中试电站烟气旁路减温减压

贾汪PFBC-CC燃煤联合循环发电中试电站的烟气旁路系统是机组启动或烟气轮机甩负荷和发生故障时高温高压烟气的安全通道,旁路中的减温减压装置是其     

减温减压装置增设旁路管的探讨

<正> 在热电厂中,通常备有减温减压装置,用以将高参数蒸汽的压力和温度降低至符合热用户的要求,以作热用户的备用汽源,保证热用户的生产用汽。通常这一减温减压装置是不设旁路管的,因为高参数的蒸汽不符合热用户的要求。自国务院批准建设43项节能项目以来,许多工厂根据用汽情况和为了合理使用能源,先     

火电机组不同灵活性改造方式盈亏平衡电价的计算及对比分析

阐述了火电机组不同灵活性改造方式的技术特点，提出了盈亏平衡电价的定义和计算原则并给出了不同灵活性改造方式盈亏平衡电价的计算方法，以某350MW超临界机组为例，计算并对比分析了固体储热式电锅炉、电极式电锅炉与蓄热罐组合、主蒸汽减温减压与蓄热罐组合、液流电池、锂离子电池以及机组启停调峰6种灵活性改造方式的盈亏平衡电价，得出主蒸汽减温减压与蓄热罐组合盈亏平衡电价最低，锂电池盈亏平衡电价最高的结论，通过计算灵活性改造方式的盈亏平衡电价可以指导电厂进行灵活性改造决策。     

造纸企业热电联产机组蒸汽梯级利用探讨

结合某造纸企业热电联产机组蒸汽使用现状及供热需求,提出蒸汽梯级利用的方案。背压机组替代减温减压装置是蒸汽合理利用的有效途径,可提高造纸企业能源利用效率。     

减温减压装置中减温器结构的设计与研究

结合我国原减温减压装置中减温器的结构,分析和研究了新型减温器的工作原理和结构特点,指出了新型减温减压装置中减温器结构设计的合理性和可行性。     

Experimental study of heat transfer coefficient with rectangular baffle fin of solar air heater

This paper presents an experimental analysis of a single pass solar air collector with, and without using baffle fin. The heat transfer coefficient between the absorber plate and air can be considerably increased by using artificial roughness on the bottom plate and under the absorber plate of a solar air heater duct. An experimental study has been conducted to investigate the effect of roughness and operating parameters on heat transfer. The investigation has covered the range of Reynolds number Re from 1259 to 2517 depending on types of the configuration of the solar collectors. Based on the experimental data, values of Nusselt number Nu have been determined for different values of configurations and operating parameters. To determine the enhancement in heat transfer and increment in thermal efficiency, the values of Nusselt have been compared with those of smooth duct under similar flow conditions.     

加热器端差对机组热经济性影响的定量分析方法

建立了定流量下加热器端差对机组热经济性影响的数学模型。该模型针对加热器的不同类型进行了讨论,应用时不再需要单独计算端差变化对锅炉吸热量的影响,并全面考虑了热力系统的结构特点及辅助汽水系统,从整体上定量分析加热器端差对机组热经济性的影响,为火电机组节能降耗以及热力系统定量分析提供了理论依据。对某600MW机组进行了算例分析,表明端差越大,机组的热经济性越低;端差越小,机组的热经济性越高。     

Computation of thermal properties of CMSP shell and tube heat exchanger using different types of helical baffles

This paper investigates the flow and thermal properties of a combined multiple shell pass (CMSP)-shell and tube heat exchanger (STHE) with the provision of unilateral ladder-type helical baffle (ULHB) and continuous helical baffle (HB) in the outer shell pass of the heat exchanger. Two CMSP-STHEs with ULHB and HB, respectively, are compared with the traditional STHE having segmental baffles (SG-STHE) using the computational fluid dynamics method. The computational outcomes are validated with the empirical correlations of the Kern and Esso method. The Reynolds-averaged Navier–Stokes-based standard k–ω turbulence model accurately predicts the heat transfer (HT) rate and pressure drop. The computed results of HT rate, pressure drop, and logarithmic mean temperature difference corresponding to various mass flow rates (m) for three STHEs are presented. The results show that the overall HT rate of CMSP (ULHB)-STHE and the CMSP (HB)-STHE at the same mass flow rate are nearly 28.3% and 14.8% larger than that of traditional SG-STHE, respectively. Furthermore, the overall area-weighted average pressure drop (ΔP) of CMSP (HB)-STHE is smaller than that of SG-STHE by 26.5% at the same mass flow rate (m) and for CMSP (ULHB)-STHE it is larger by 2% than that of traditional STHE. Based on the above results, it is concluded that the CMSP (ULHB)-STHE is a suitable replacement for the conventional SG-STHEs.     

扰流空心翅片式微流道液冷板流动换热特性研究

液冷板冷却技术是解决高功率芯片热管理问题最有前途的技术之一,带翅片结构的液冷板具有低流阻、低热阻的优势,因而受到广泛关注。目前翅片结构多以实心为主,空心交错翅片对液冷板散热能力和压降等冷却特性的影响尚未得到系统的研究。对此,设计了空心交错翅片液冷板,采用数值模拟的方法研究进口温度和流量对液冷板流动换热特性的影响。模拟结果表明,空心翅片式液冷板具有良好的散热性能,随着进口温度的升高,液冷板温度不均匀性逐渐降低,但降低趋势有所减缓,而流量的增大对降低平均热阻有显著的作用,当进口流量超过1.2 L/min时,液冷板的平均热阻可低于0.04℃/W;然而,流量的增大也提高了流动阻力,当流量增大至1.7 L/min时,流体出口区域形成涡旋,产生回流区,不利于液冷板的散热效果,且流动阻力增大。     

Thermal performance of a shallow solar-pond integrated with a baffle plate

A shallow solar-pond integrated with a baffle plate is investigated theoretically and experimentally under Tanta prevailing weather conditions. A transient mathematical model is presented for the pond. The energy-balance equations for various parts of the pond are solved analytically using the elimination technique. In order to validate the theoretical model, experiments are performed under the batch mode of heat extraction with a black painted baffle plate made of stainless steel, with and without vents in the plate, for different masses of water in the upper and lower layers. It is found that the pond-water temperature decreases with increasing vent area; therefore, the baffle plate should be used without vents with shallow depths of the upper water-layer. Experiments have also been carried out using baffle plates made from Al and mica in order to study the effect of the thermal conductivity of the baffle plate on the pond’s performance. The average temperature of the pond water is found to be less dependent on the thermal conductivity of the baffle plate. It is also inferred that the present system could provide 88 L of hot water at a maximum temperature of 71 °C at 3:00 pm with a daily efficiency of 64.3% when the baffle plate is used without vents. The pond can retain hot water until 7:00 am of the next day at a temperature of 43 °C, which can be used for most domestic applications. Comparisons between experimental and theoretical results indicated that the theoretical model could be used for estimating the pond’s performance with good accuracy.     

供热机组热化发电率算法研究

热化发电率是评价供热机组经济性的一个指标，它能够表现供热机组通流效率、回热效果、供热参数和回水状况对热电联产效果的影响。根据热化发电率的定义，比较了现有的热平衡计算、简化计算方法中存在的问题，利用循环函数方法中推导出的特性系数，解决了热化发电率的精确计算模型。算例表明，新算法模型计算简捷，结果准确。     

直通式真空管空气集热器热性能实验及干燥应用

在直通式太阳能玻璃真空管空气集热器基础上改进联箱结构,并搭建测试平台对该种改进型空气集热器进行热性能实验研究。通过实验比较改进前后集热器的温升和效率,获得改进后集热器出口温度与太阳辐照度关系的线性回归方程,掌握不同空气质量流量对集热器出口温度和集热效率的影响规律,分析得到该种真空管的最佳串联个数,并对应用该种集热器的太阳能干燥系统的干燥效果进行初步测试分析。该研究结果可为太阳能空气集热干燥系统的设计及应用提供参考。     

连续型螺旋折流板换热器结构及性能研究

连续型螺旋折流板换热器一直受限于加工工艺而未能得到广泛应用,本文提出采用加装中芯管的方法,实现了连续型折流板的加工,并给出了连续型折流板螺旋升角和螺旋包络面的计算方法。利用Fluent软件,与现今应用较广泛的1／4椭圆形折流板换热器的流动和换热特性进行模拟比较。结果表明,连续型折流板换热器换热能力提高了近一倍,综合性能系数也提高了近30％,虽然1／4椭圆折流板压力降较小,但其折流板的漏流,也严重降低了传热能力。为在工程中推广应用连续型螺旋折流板换热器,本文提供了理论依据和技术支撑。     

Comparative study of room temperature control in buildings with and without the use of PCM in walls

The concept of thermal energy storage in building gains a specific importance in the present energy scenario related to energy consumption and indoor thermal comfort. The material used to store the thermal energy which undergoes a phase change referred as PCM and it is considered as a possible solution for reducing energy consumption in the building by storing and releasing heat within a certain temperature range; it raises the building inertia and also stabilizes indoor air temperature fluctuations. The room temperature is controlled by imposing PCM inside the walls. An attempt has been made to compare room air temperature with and without the use of PCM inside the walls of constructed modular building unit. The PCM imposed modular building shows the reduced temperature fluctuations in room, the PCM absorbs and liberates excess heat which is gained from the outer side of the room and maintains constant inner room temperature. The PCM imposed walls of modular building unit have an ability to reduce 10–30% of heat load in comparison with the plain wall. The results showed that reduction in room temperature is about 2–4°C and it has been concluded that the PCM imposed modular building unit has more energy saving opportunities than normal modular building unit.     

Single and double pass solar air heaters with wire mesh as packing bed

The thermal performances of single and double pass solar air heaters with steel wire mesh layers are used instead of a flat absorber plate are investigated experimentally. The effects of mass flow rate of air on the outlet temperature and thermal efficiency were studied. The results indicate that the efficiency increases with increasing the mass flow rate for the range of the flow rate used in this work between 0.012 and 0.038 kg/s. For the same flow rate, the efficiency of the double pass is found to be higher than the single pass by 34–45%. Moreover, the maximum efficiencies obtained for the single and the double pass air collectors are 45.93 and 83.65% respectively for the mass flow rate of 0.038 kg/s. Comparison of the results of a packed bed collector with those of a conventional collector shows a substantial enhancement in the thermal efficiency.