用于联合循环机组的复合循环间接空冷系统设计及分析

论述了联合循环机组发展前景,阐述燃气-蒸汽联合循环采用间接空冷系统的重要性。介绍了发电厂空冷系统,分析了各种空冷技术应用于生产实际的优缺点,提出联合循环采用复合循环间接空冷系统模式,分别对其设计计算过程进行了讨论,对压缩机-空冷凝汽器性能影响因素进行了分析,对性能变化规律进行了研究。结果表明：复合循环间接空冷系统设计要综合考虑气象条件,尤其是环境风速、制冷量和空冷电站平面布局的影响。     

空冷汽轮机低压排汽面积选择和变工况特性分析

根据我国西北某地区的典型环境温度对600MW直接空冷机组的低压末叶片进行优化,得到合理的低压排汽面积,同时根据末级叶片的设计特点对其变工况特性进行分析,从而对620mm末叶片的变工况性能有一定了解。分析结果表明,设计背压为15kPa.a时,末叶片采用620mm比较合适;采用专用强化叶型、控制反动度、控制攻角等方法的620mm末叶片可以有效保证空冷机组变工况安全高效运行。     

对直接空冷机组排汽装置的发展趋势的研究

随着空冷机组容量的不断扩大,排汽装置已由单一型逐渐地向多功能型发展。较为详细地介绍了设置除氧功能排汽装置的必要性,阐述了除氧装置的几种布置结构,并对具有表面式换热器的排汽装置的应用特点进行了简要描述。     

直接空冷系统排汽管道特性研究

为了研究直接空冷机组排汽管道内水蒸汽的流动特性,采用CFD技术,对某台200MW直接空冷机组排汽管道内的水蒸汽流场进行了三维数值模拟.根据数值计算结果,在直接空冷大直径排汽管道内的弯头和三通等处安装导流叶,不仅有利于减小工质在管道内的流动阻力和实现管道内工质的均匀分布,而且有利于提高直接空冷系统的整体热效率.     

300MW直接空冷机组排汽装置的三维数值研究

采用SIMPLE算法和κ-ε模型,对内王低压加热器的300MW直接空冷机组排汽装置的内部漉场进行了三维数值模拟,得到了整个排汽装置内部流场的速度分布情况.结果表明,由于内王式低压加热器的影响和裤汽装置接颈部棱台的扩散作用使排汽装置接颈出口流场速度分布产生很大的不均匀性,从而导致蒸汽在排汽装置内流动的汽阻和压损增大,最终影响到机组运行的经济性.该数值模拟结果对直接空冷汽轮机择汽装置的完善化设计及改造,具有一定的指导作用.     

直接空冷枝状排汽管道系统内导流装置的优化设计

对德国基伊埃(GEA)公司发明专利——枝状直接空冷排汽管道系统进行研究。建立某2×600MW机组直接空冷排汽管道内湿蒸气两相流动和传热的数学模型;利用数值传热学软件Fluent对典型汽轮机工况下的排汽状况进行了数值模拟;对二维管道内湿蒸气速度场、温度场和两相场的模拟、分析和研究。模拟结果表明:专利提出的简单几何原则分流方法,无法实现排汽的均匀分配。针对不同形式的直接空冷枝状排汽管道系统应进行详细的优化设计,并提出了枝状排汽管道系统导流装置的基本设计原则。     

直接空冷600MW汽轮机排汽装置的结构、安装与运行

对直接空冷600MW机组排汽装置的结构特点、安装与试验要求、方法及运行进行了论述,让读者对排汽装置有比较全面的了解,对电厂的现场安装、试验及运行起指导作用。     

一种全新型太阳能供热与制冷联合循环复合系统──Ⅰ.系统构造思想

提出一种利用太阳能作为驱动热源的固体吸附式制冷与供热联合循环方法,描述了太阳能制冷与供热联合循环的工作原理,并对循环装置内各子系统部件的热力循环过程和能量转化过程作了理论分析与计算说明。采用该联合循环装置,可实现用同一集热器白天加热的热水供夜间使用,夜间制的冰供白天使用的目的     

Performance Analysis and Evaluation of a Supercritical CO2 Rankine Cycle Coupled with an Absorption Refrigeration Cycle

The utilization of sensible waste heat such as flue gas and industrial surplus heat is essential for energy saving. Supercritical CO2 power generation cycle is a promising way to be used in this field. In this paper, a new supercritical CO₂ Rankine cycle coupled with an absorption refrigeration cycle is proposed, which consists of a reheating supercritical CO₂ cycle, a mixed-effect Li Br-H₂O absorption refrigeration cycle and solar subsystem including evacuated-t...     

电冰箱能耗与制冷系统优化设计及制冷循环分析

电冰箱节能研究是一重要课题,其中制冷系统优化设计及制冷循环形式是重要两环,已有相关文献对此进行报道,本文据项目研究实际情况,对制冷系统优化设计提出自己的观点,对制冷循环及其存在问题和解决方案做进一步分析,研制的BCD-186CHS节能冰箱日耗电0．39kWh,在节能状态下耗电0．35kWh以下。     

一种全新型的太阳能供热与制冷联合循环复合系统

在提出了太阳能供热与制冷联合循环及系统动态仿真的基础上,制作了一台供热与制冷联合循环的实验样机,并模拟一定的太阳能日照辐射量进行了实验研究。结果表明,在复合机系统接受的加热总量达４９ＭＪ的工况下,系统对外产出－２℃的冰１０．５ｋｇ,系统循环的ＣＯＰｃｙｃｌｅ＝０．３８６,ＣＯＰｓｙｓｔｃｍ＝０．０６７;与此同时,系统还对外产出了９８℃的热水１５０ｋｇ,供热效率为η＝０．７５８。该实验的成功实现,为     

三缸两排汽200MW间接空冷汽轮机通流部分改造

改进型200MW汽轮机及大型空冷汽轮机的不断投产,为200MW间接空冷汽轮机改造提供了技术储备。末级叶片的优化设计是发展空冷机组重要条件之一,正是由于选择了合适的末级叶片,对丰镇电厂的机组改造取得了成功。     

轻型汽车发动机台架实验用排气装置的设计与分析

通过分析轻型汽车发动机台架实验用排气装置的现状,并指出缺点和不足,提出改进方案,设计一种适用多类型轻型汽车发动机台架实验的新型排气装置,在x,y,z,x,y,z六个方向有一定自由度和伸缩空间,这样解决在安装过程的空间干涉问题,达到一机多用,减少研发与测试成本并可缩短研发周期,并在发动机台架下与传统排气装置进行了发动机外特性对比,两种排气装置的实验结果基本一致,证明新型排气装置是可行的。     

Solar Powered Cascading Cogeneration Cycle with ORC and Adsorption Technology for Electricity and Refrigeration

As a renewable source, solar energy has received more and more attention in recent years. Solar energy can readily provide heat efficiently within the temperature range of 70–100°C. For the utilization of this energy source, a cascading cycle was designed and was discussed. An organic Rankine cycle (ORC) and an adsorption refrigeration cycle were combined to provide the first- and second-stage energy conversion cycle, respectively. In the analysis, R600 was used as the working fluid for the ORC and a silica gel–water working pair was analyzed for the adsorption refrigeration cycle. The energy efficiency for electrical generation and refrigeration, as well as the exergy efficiency of the cascading cycle, was assessed. For an environmental temperature of 30°C and a refrigeration temperature of 12°C, the results showed that typically 1 kW of electricity and 6.3 kW of refrigeration could be generated from approximately 15 kW heating power. The electricity generation efficiency was between 0.1 and 0.15, while the refrigeration coefficient of performance was approximately 0.8. The exergy efficiency was found to be between 0.84 and 0.89 and between 0.32 and 0.46 for the single ORC and adsorption refrigeration cycle, respectively. The overall exergy efficiency was between 0.56 and 0.74.     

Analysis of a Finned Heat Exchanger Working in an Adsorption Refrigeration System Using Zeolite and Methanol

A new refrigeration system that uses a specially designed finned plate heat exchanger and works with zeolite and methanol is proposed. The integration of heat transfer and adsorption via a finned surface coated with zeolite CBV 901 and the use of a connected, twin active bed system to enable heat recuperation are novel features. The thermophysical properties of zeolite and methanol were first studied with the intention of designing a high performance heat exchanger (generator) for the adsorption refrigeration system. Here, the major problem is related to poor conductivity at the interface between the heat exchanger and the zeolite. The adsorbent must be heated (desorption phase) and then cooled (adsorption phase) back to ambient temperature in order to complete a thermodynamic cycle. To manufacture a sufficiently small system, there must be high rates of heat transfer in and out of the adsorbent. Therefore, the surface of the heat exchanger is finned in order to increase the heat transfer area (the fins are coated with 2 mm layer of specially prepared zeolite paste). The following characteristics were estimated from initial calculation: heating temperature, 120°C; outside tube temperature, 119.6°C; middle fin temperature, 117°C; and coated layer of zeolite paste temperature, 115.3°C. The mathematical code developed to calculate the effects of operating conditions and the Coefficient of Performance (COP) was presented at HPC 2001 in Paris. It is based on the Dubinin-Astakhov equation and thermodynamic analyses. The results obtained shows that 0.535 is the COP for a single bed and 0.925 for a double bed.     

Thermal and Exergy Analysis of an Organic Rankine Cycle Power Generation System with Refrigerant R245fa

Abstract

In this paper, the performance of an organic Rankine cycle (ORC) power generating system operating with refrigerant R245fa was investigated when heat source temperature was below 200?°C. It was found the system thermal efficiency increased but the exergy efficiency of the evaporator decreased with the increase of the heat source temperature. It was also obtained that the exergy efficiency of the evaporator could reach70% when the heat source temperature was 80?°C, which was high enough to prove that the transformation efficiency between the waste heat and the electricity power was ideal. In the simulation model, the area of different parts of the heat exchanger were considered to be varied, flow rate of the waste heat and working medium, the system thermal and exergy efficiency of the evaporator were respectively calculated, the different parameter change regarding the performance influences of the ORC system were simulated. The results can be considered as a reference to research on the design of ORC power generating systems and heat exchangers.