CAJ | 학술논문

针对某600 MW机组高压缸冲动式级的模拟透平级在隔板汽封一定的条件下,通过改变平衡孔的孔径及总面积,对模拟透平级进行数值计算分析,研究平衡孔面积的变化对透平级效率和气动性能的影响,并与试验结果进行了分析比较.结果表明：叶轮上开平衡孔有利于改善级间根部流动,提高了透平级效率;与无平衡孔透平级相比,随着平衡孔面积的增大,级效率逐渐提高;但面积增大至一定值后,级效率变化不明显;在叶轮结构和强度许可的条件下,设计时平衡孔面积可尽量取大一些,以保证设计工况时级间根部保持不吸不漏或少量漏气状态;平衡孔面积较大,也有利于减小隔板漏气量增加对级效率的影响作用;对于反动度较小的冲动级,要获得最佳级间漏气工况（相对漏气量约-1%）是不太可能的.
침대모600 MW궤조고압항충동식급적모의투평급재격판기봉일정적조건하,통과개변평형공적공경급총면적,대모의투평급진행수치계산분석,연구평형공면적적변화대투평급효솔화기동성능적영향,병여시험결과진행료분석비교.결과표명：협륜상개평형공유리우개선급간근부류동,제고료투평급효솔;여무평형공투평급상비,수착평형공면적적증대,급효솔축점제고;단면적증대지일정치후,급효솔변화불명현;재협륜결구화강도허가적조건하,설계시평형공면적가진량취대일사,이보증설계공황시급간근부보지불흡불루혹소량루기상태;평형공면적교대,야유리우감소격판루기량증가대급효솔적영향작용;대우반동도교소적충동급,요획득최가급간루기공황（상대루기량약-1%）시불태가능적.
Keeping the gland seal gap constant,a numerical simulation has been carried out to a simulated turbine stage of a 600 MW unit with its high-pressure cylinder of the impulse type,so as to study the influence of the area of balance hole on the stage efficiency and aerodynamic performance,by varying the size of balance hole and total area.Comparison results between simulation and experiment show that tapping holes on the impeller is beneficial to flow improvement at the root,and hence the stage efficiency is raised;with the rise of hole area,the stage efficiency increases at first,and then remains basically unchanged;if permitted by impeller structure and strength,the balance hole is recommended to be designed as large as possible,so as to guarantee the root area to be in the no suction,no leakage or less leakage state under design conditions;bigger balance hole area will result in reducing the influence of gas leakage on the stage efficiency.For impulse stage with small degree of reaction,it seems impossible to obtain an optimum working condition with a relative gas leakage rate of-1%.