一种应急柴油机启动性能监测评估方法

A MONITORING AND EVALUATION METHOD ON THE START-UP PERFORMANCE OF EMERGENCY DIESEL ENGINE

应急柴油机是核电站最后一道安全屏障,核安全准则要求其在紧急情况下,能够在10 s内启动达到额定转速(如1 500 r/min)并具备加载条件,因此其启动性能尤为重要。启动过程中,高压空气的做功能力是启动成功的关键要素。旨在研究一种基于振动监测的高压(国内机组一般为40 bar·g)空气做功能力分析方法,进而评估启动性能。获得的大量监测数据表明:高压空气快速充入气缸会产生高频(约11 kHz)的气流激振冲击,且该冲击相位会随着转速升高而不断后移。首先结合Teager能量算子和一种自适应阈值冲击定位方法自动捕捉启动阶段每一周期各缸的高压气体冲击区域,然后提取局部冲击包络能量用于表征高压空气的做功能力,最后采用灰色评价法进行综合评估。实际测试结果验证了此方法的有效性,具有推广应用的价值。

Emergency diesel engine is the last safety barrier for nuclear power plants. Nuclear safety criteria require that it can start up to rated speed( such as 1 500 r/min) within 10 seconds in an emergency and have loading conditions,so its startup performance is particularly important. During the start-up process,the power of high-pressure air is a key factor for success.In this paper,a vibration-based method by analyzing high-pressure air( domestic units are generally 40 bar·g) power to evaluate starting performance is presented. The large amount of monitoring data obtained indicates that high-pressure air is rapidly charged into the cylinder to generate high-frequency( approximately 11 kHz) gas exciting impact,and the impact phase will continue to shift backward with increasing speed. Firstly,the Teager energy operator and an adaptive threshold impact location method were used to automatically capture the high pressure gas impact area of each cylinder in each cycle of the start-up phase. Secondly,the energy of the local impact envelope was extracted to characterize the function of the high-pressure air. Finally,the gray evaluation method carried out a comprehensive assessment. The actual test result verifies the effectiveness of this method and has the value of popularization and application.