第56卷第1期 2014年2月
汽轮机技术 TURBINE TECHNOLOGY
高中压合缸汽轮机中压平衡活塞汽封
漏汽率影响因素分析
李勇，黄生文，曹丽华
（东北电力大学能源与动力工程学院，吉林132012）
Vol No. 1 Feb.2014
摘要：变汽温试验法测定中压平衡活塞汽封蒲汽率时认为变汽温试验两工况下的中压平衡活塞汽封漏汽率相同，实际上，中压平衡活塞汽封漏汽率受机组运行状态的影响，并不为定值。首先对中压平衡活塞汽封漏汽率的影响因素进行理论分析，然后通过变工况详细计算定量分析再热器减温水量、机组负荷以及各高压加热器上、下端差变化对漏汽率的影响，计算表明，再热器减温水量、再热蒸汽温度、中压平衡活寒汽封前蒸汽温度、2号高压加热器下端差以及3号高压加热器上端差变化对漏汽率影响较大，而漏汽率基本不随1号、2号高压加热器上端差和1号加
热器下端差变化，最后利用热平衡图数据对变工况计算分析结果的正确性进行了验证。关键词：汽轮机；中压平衡活塞汽封漏汽率；影响因素
分类号：TK263.2
文献标识码：A
文章编号：1001-5884(2014)01-0013-05
Analysis on the Influencing Factors of Intermediate Pressure Balance Piston SealLeakageRateinSteamTurbinewithaCombinedHP-IPCylinder
LI Yong,HUANG Sheng-wen,CAO Li-hua
(School of Energy and Power Engineering, Northeast Dianli University,Jilin 132012, China)
Abstract; The existing temperature variation test method which is used to determine intermediate pressure ( IP) balance piston seal leakage rate was put forward based on the point of view that the values of IP balance piston seal leakage rate in two different working conditions are identical. Actually,the IP balance piston seal leakage rate is not a constant value,for it is affected by many operating parameters. Firstly ,theoretical analyses of the factors which affect the IP balance piston seal leakage rate were conducted. Secondly, quantitative analysis of influence on IP balance piston seal leakage rate caused by the reheater desuperheating water flow, the unit load, and terminal temperature difference of high-pressure heater were carried out through detailed variable condition calculations,the results show that the influence factors such as the reheater desuperheating water flow, reheat steam temperature, steam temperature before IP balance piston seal, the drain cooler temperature difference of No. 2 high-pressure heater and the terminal temperature difference of No. 3 high-pressure heater have significant influence on the IP balance piston seal leakage rate, and the leakage rate remain unchanged when the terminal temperature difference of No. 1 and No. 2 high-pressure heaters changes, as well as the drain cooler temperature difference of No. 1 high-pressure heater. Finally ,the calculation adopting heat balance diagram data were proceeded in order to verify the correctness of theoretical analysis and quantitative analysis above.
Key words:steam turbine;intermediate pressure balance piston seal leakage rate;influencing factor
来一定的问题，例如，实际运行过程中尤其是机组启停过程
0前言
对于高中压合缸反动式汽轮机，高、中压缸之间的高压平衡活塞、中压平衡活塞两侧蒸汽压差较大，存在由高压缸调节级后到中压缸第一级喷嘴后的漏汽间题，这部分漏汽称为中压平衡活塞汽封漏汽，漏汽量的大小由中压平衡活塞汽封结构及汽封段前后蒸汽参数所决定。中压平衡活塞汽封漏汽的存在对于汽轮机内、外缸和高中压缸进汽部分转子的冷却以及汽轮机轴向推力的平衡有一定的好处，但同时也带收稿日期：2013-08-08
中，由于动静部分运行磨损，中压平衡活寒汽封间隙远大于设计值，汽封漏汽量急剧增多，如果不能准确确定漏汽量的大小，将导致由中压缸进汽参数和排汽参数计算的中压缸效率不能反映中压缸内部通流性能以及机组热耗率的计算偏差，进而影响汽轮机运行经济状况的准确评价["]。
为此，国内外有关学者提出了利用变汽温热力试验的方法间接计算中压平衡活塞汽封漏汽率（即中压平衡活塞汽封漏汽流量与中压缸进口再热蒸汽流量之比）[2-9]，文献[2-8]中的变汽温法是根据变汽温前后两工况下中压平衡活塞
基金项目：吉林省科技发展计划资助项目(20110409）；吉林省教育厅"十二五"科学技术研究项目（吉教科合字[2012]第93号）。作者简介：李勇（1964-），男，教授，工学博士。从事汽轮机运行性能诊断，优化运行技术研究。