基于声发射信号信息(火用)贴近度的滑动轴承润滑状态诊断方法

为了有效判断滑动轴承润滑状态,避免基于状态的润滑故障诊断方法的低区分度和准确度问题,基于滑动轴承润滑状态过程信息,提出基于信息■的滑动轴承润滑状态诊断方法。在300MW汽轮发电机组模拟转子实验台上采集滑动轴承干摩擦、半干摩擦和液体摩擦3种润滑状态的声发射信号,利用信息■贴近度和方差的方法对声发射信号进行分析,并对各种润滑状态进行有效区分。结果表明:基于声发射信号信息■贴近度和方差的方法能够实现对不同润滑状态的准确诊断,且信息利用率和判别区分度均高于信息熵分布区间诊断方法。     

热经济系数(火用)分析法在能源管理中的应用

通过对热动力装置系统的(火用)分析,指出了(火用)在能源中的作用.提出了一种对(火用)能系统进行热经济性分析决策的方法-热经济系数法,并以实例探讨了其方法在方案选择中的应用.总结了(火用)效率与热经济系数之间的关系.     

土壤源热泵系统的[火用]分析

对组成土壤源热泵系统的3个回路以及整个系统的制冷和制热工况进行了全面的(火用)分析,分别给出了它们的(火用)损失、(火用)效率、(火用)损率、(火用)损系数以及热力学完善度的表达式.结果表明:在对系统进行(火用)分析时,必须将这几个指标结合起来使用.在整个系统中,(火用)损率最大的部件是压缩机,而(火用)效率与热力学完善度最低的却是土壤热交换器.因此,压缩机和土壤热交换器是整个系统改进的首要对象.     

含相变过程的机械[火用]计算方法

机械(火用)作为广泛使用的稳流物系的焓(火用)的两个组成部分之一,其计算正确与否直接影响到(火用)分析结果的正确性.通过分析发现,传统的机械(火用)计算方法没有充分考虑机械(火用)计算路径下可能存在的相变及其影响.为此,通过对定温变压过程下物态变化及其做功能力的理论分析,提出了适用于含相变过程的完整的机械(火用)计算方法.应用该方法及传统方法对水的焓(火用)进行比较计算.结果表明,对存在相变过程的机械(火用)的计算,传统计算方法的误差较大,而提出的计算方法准确可靠,具有较强的实用价值.     

电站锅炉传递描述

能量的传递和转换必然伴随其"质"--(火用)的传递和转换.能量在传递和转换过程中其量守恒,而炯在传递和转换过程中其量不守恒,因此(火用)必有其独特的传递和转换规律.常规(火用)平衡分析综合热力学第一定律和第二定律,以(火用)效率为评价指标,属于静态热力学研究.参照工程(火用)传递评价准则,提出了堋传递系数、(火用)流密度、(火用)损率等评价指标,并针对某台锅炉机组进行了(火用)传递分析,通过与常规的传热及(火用)平衡分析比较,提供了一些新的技术评价信息.     

LF精炼工艺的[火用]分析

采用(火用)分析方法,对LF精炼过程进行了(火用)分析.LF内部(火用)损失和外部(火用)损失分别占总(火用)损失的29%和71%,外部(火用)损失为主要(火用)损失.电能无用功所引起的(火用)损失占总(火用)损失的62.28%,减少电能无用功引起的炯损失是提高(火用)效率和节能的主要方向.     

冷量(火用)与热量(火用)计算方法的统一性研究

以热力学第一、二定律为基础,结合(火用)、妩的基本定义,探讨了冷量(火用)、冷量妩的计算方法,指出了当前(火用)分析理论体系中存在的'冷量(火用)、冷量妩计算方法不能与热力学第一定律相统一'的问题,提出了新的计算方法,使得冷量(火用)计算方法更科学、严谨.     

基于等效(火用)降品质系数的火力发电机组热经济学分析

提出等效(火用)降品质系数θe的概念,根据θe的大小判断燃料(火用)流在各热力设备处的热量(火用)变功能力,进而确定其(火用)单价,从(火用)变功的角度合理构造了热经济学补充方程;利用该系数对某1 000MW机组热力系统进行了(火用)流的(火用)单价计算,并将计算结果与Valero方法、能质系数法进行了分析比较.该系数不仅体现了(火用)流的品质和价格,而且考虑到设备处的热量(火用)变功能力对(火用)成本的影响,使(火用)成本计算更科学合理.     

火电厂辅助汽水系统定量(火用)分析计算通用模型的研究与应用

根据(火用)平衡方程,利用(火用)效率的概念对火电厂各回热加热器进行了分析,通过论证推导,提出了火电机组辅助汽水系统定量(火用)分析计算的通用模型.运用此模型定量计算某电厂328.5MW机组高压缸轴封漏汽利用对汽轮机装置系统(火用)效率的影响;为辅助系统局部定量分析提供了便利方法.     

用于集中供热的冷凝热回收(火用)分析

用(火用)平衡分析法对西山热电的原集中供热系统和冷凝热回收后的集中供热系统进行了(火用)流分析.两者对比表明,冷凝热回收用于集中供热是实现节能减排的一条有效途径.     

能源转换利用的火用分析概述

本文对有用能——火用的概念和起源做了简单介绍,并分别概述了化学火用和累积火用的基本理论以及在应用上的意义。指出了当前火用分析存在的问题,进而提出了“投入产出火用函数”,并以此对可再生能源、不可再生能源以及循环能源的转换利用进行了火用分析,得出了只有不断加大可再生能源在能源结构中的比例和提高转换过程的火用效率,才能减缓地球火用衰减的结论。     

试论工程(火用)传递的基本方式

基本Yong传递方式的科学确定,对复杂Yong传递过程或系统的研究极具价值。在分析评述现有研究成果的基础上,提出了作为基本Yong传递方式的充要条件。对多种复杂Yong传递系统的分解、分析,积累了丰富的Yong传递形式资料。据此提出四种基本Yong传递方式,作为应用列举了二个复杂Yong传递系统分解实例。     

工程常见输(火用)元的特性准则及其计算

输元是组成传递模型的基本单元.提出三类9项输元特性准则.研究确定传热传递、能量转换传递、传质传递三大类8种典型输元的特性准则,并给出了相应的计算式或表达式,为规范建立基本工程传递模型、简化复杂系统的工程传递分析提供了基础.     

Turkey's sectoral energy and exergy analysis between 1999 and 2000

This study analyses sectoral energy and exergy utilization in Turkey between 1999 and 2000. Total energy and exergy utilization efficiencies are calculated to be 43.24 and 24.04% in 1999, and 44.91 and 24.78% in 2000, respectively. In order to calculate these efficiency values, Turkey is subgrouped into four main sectors, namely utility, industrial, transportation and commercial‐residential. The energy efficiency values are found to be 23.88, 30.10, 68.97 and 57.76% in 1999, and 23.71, 30.11, 68.81 and 57.05% in 2000 for transportation, utility, industrial and commercial‐residential sectors, respectively. Besides this, the exergy efficiency values are obtained to be 23.80, 30.28, 35.97 and 8.12% in 1999, and 23.65, 30.47, 35.51 and 8.02% in 2000 for the same order of sectors. The present study has clearly shown the necessity of the planned studies towards increasing exergy efficiencies in the sectors studied. Copyright © 2004 John Wiley & Sons, Ltd.     

单元初始火用效率和火用流价值分布

分析了火用的不等价性,在此基础上提出了火用弹性系数、初始火用损耗率等概念.以火用弹性系数为计算基础,分析了在单一系统内各组元火用效率对整个系统火用效率的影响,导出了初始火用损耗率的计算方法,并以实例进行了分析计算.分析表明系统内各组元的单位火用所消耗的初始火用更能反映系统各组元的火用耗特性,从而有利于更科学地分析系统各单元的节能潜力.     

Exergoeconomic analysis of a combined heat and power (CHP) system

This study deals with exergoeconomic analysis of a combined heat and power (CHP) system along its main components installed in Eskisehir City of Turkey. Quantitative exergy cost balance for each component and the whole CHP system is considered, while exergy cost generation within the system is determined. The exergetic efficiency of the CHP system is obtained to be 38.33% with 51 475.90 kW electrical power and the maximum exergy consumption between the components of the CHP system is found to be 51 878.82 kW in the combustion chamber. On the other hand, the exergoeconomic analysis results indicate that the unit exergy cost of electrical power produced by the CHP system accounts for 18.51 US$ GW^?1. This study demonstrates that exergoeconomic analysis can provide extra information than exergy analysis, and the results from exergoeconomic analysis provide cost‐based information, suggesting potential locations for the CHP system improvement. Copyright © 2007 John Wiley & Sons, Ltd.     

Exergy analysis of a coal‐based 210 MW thermal power plant

In the present work, exergy analysis of a coal‐based thermal power plant is done using the design data from a 210 MW thermal power plant under operation in India. The entire plant cycle is split up into three zones for the analysis: (1) only the turbo‐generator with its inlets and outlets, (2) turbo‐generator, condenser, feed pumps and the regenerative heaters, (3) the entire cycle with boiler, turbo‐generator, condenser, feed pumps, regenerative heaters and the plant auxiliaries. It helps to find out the contributions of different parts of the plant towards exergy destruction. The exergy efficiency is calculated using the operating data from the plant at different conditions, viz. at different loads, different condenser pressures, with and without regenerative heaters and with different settings of the turbine governing. The load variation is studied with the data at 100, 75, 60 and 40% of full load. Effects of two different condenser pressures, i.e. 76 and 89 mmHg (abs.), are studied. Effect of regeneration on exergy efficiency is studied by successively removing the high pressure regenerative heaters out of operation. The turbine governing system has been kept at constant pressure and sliding pressure modes to study their effects. It is observed that the major source of irreversibility in the power cycle is the boiler, which contributes to an exergy destruction of the order of 60%. Part load operation increases the irreversibilities in the cycle and the effect is more pronounced with the reduction of the load. Increase in the condenser back pressure decreases the exergy efficiency. Successive withdrawal of the high pressure heaters show a gradual increment in the exergy efficiency for the control volume excluding the boiler, while a decrease in exergy efficiency when the whole plant including the boiler is considered. Keeping the main steam pressure before the turbine control valves in sliding mode improves the exergy efficiencies in case of part load operation. Copyright © 2006 John Wiley & Sons, Ltd.     

Exergetic performance evaluation of a combined heat and power (CHP) system in Turkey

This study deals with the exergetic performance assessment of a combined heat and power (CHP) system installed in Eskisehir city of Turkey. Quantitative exergy balance for each component and the whole CHP system was considered, while exergy consumptions in the system were determined. The performance characteristics of this CHP system were evaluated using exergy analysis method. The exergetic efficiency of the CHP system was accounted for 38.16% with 49 880 kW as electrical products. The exergy consumption occurred in this system amounted to 80 833.67 kW. The ways of improving the exergy efficiency of this system were also analysed. As a result of these, a simple way of increasing the exergy efficiency of the available CHP system was suggested that the valves‐I–III and the MPSC could be replaced by a 3500 kW‐intermediate pressure steam turbine (IPST). If the IPST is installed to the CHP system (called the modified CHP (MCHP) system), the exergetic efficiency of the MCHP system is calculated to be 40.75% with 53 269.53 kW as electrical products. The exergy consumption is found to be 77 444.14 kW in the MCHP system. Copyright © 2006 John Wiley & Sons, Ltd.     

富氧燃煤锅炉的效率分析

采用锅炉效率的分析方法对某电站300MW锅炉在O2/CO2气氛下的各项损失和锅炉效率进行了计算,并与相同条件的空气气氛下的各项损失和锅炉效率进行了比较。结果表明,采用O2/CO2的富氧燃烧技术可大大提高锅炉热效率,并相应提高锅炉的效率,而燃烧过程和传热过程的损失仍是锅炉的主要损失。