农业工程学报2024，Vol.40Issue(24)：49-58,10.DOI:10.11975/j.issn.1002-6819.202406034
转速变换方式对变速过程中混流泵稳定性的影响
Effects of speed conversion mode on the stability of mixed-flow pumps during speed varing-process
摘要
Abstract
Speed conversion has posed a significant impact on the stability of the mixed flow pump in the operation of variable speed.Taking the mixed flow pump as the research object,this study aims to collect the displacement signals of shaft vibration and pressure pulsation inside the pump under different speed conversion modes using a synchronous acquisition system.A systematic analysis was made to clarify the influence of speed conversion modes on the stability of mixed-flow pumps.The results show that the position of the shaft center was inconsistent with before the start of speed conversion at the end of speed conversion.There was the smallest offset distance of the quartic power speed conversion,which was 0.075 mm.The vortex motion of shaft vibration was the most stable under the speed conversion to the quartic power,compared with the rest.In the quartic power speed conversion,the ratio of S(p-p)to △D was only greater than 0.33 at the end of the speed conversion.The maximum kurtosis of the two-dimensional joint was 5.67(quarter power),5.61(linear),and 5.4(quartic power),respectively,for the three-speed conversion modes.Among them,the proportion of positive joint kurtosis for the shaft vibration was 70％(quarter power),44％(linear),and 4％(quartic power),respectively.The quartic power speed conversion effectively improved the mechanical impact of shaft vibration.The main frequency of shaft vibration was the rotational frequency f under different speed conversion modes.The proportion of high amplitude region was 87.5％,62.5％,and 12.5％in the descending order of the index under the speed conversion mode.The high amplitude and high-order harmonic frequencies of shaft vibration were concentrated mainly in 2fn among the three-speed conversion modes.Phase resonance caused the amplitude of higher-order harmonics of pressure pulsation inside the impeller to be stronger than fBPF(passing frequency of impeller blades)during speed conversion.The proportions of high amplitude areas in 12fn under the three-speed conversion modes were 75％,50％,and 5％in the descending order of their indices.The main frequency of shaft vibration velocity still remained in the time-frequency of pressure pulsation inside the pump during speed conversion,indicating the high impact of shaft vibration on pressure pulsation.Finally,the improved TOPSIS was used to quantitatively evaluate the operational stability of mixed-flow pumps under speed conversion modes.The results showed that the operational stability of the mixed flow pump gradually deteriorated,as the speed increased.There was the smallest stability index of the quartic power speed conversion.The mixed flow pump has the best stability during the quartic power speed conversion,only considering shaft vibration and pressure pulsation.The findings can provide a strong reference to improve the stability of mixed flow pumps during speed conversion.关键词
混流泵/振动/主轴/转速变换/二维联合峭度/稳定性Key words
mixed flow pump/vibration/shaft/speed conversion/two-dimensional joint kurtosis/stability分类
机械制造引用本文复制引用
朱国俊,宣奕帆,冯建军,王李科,罗兴锜..转速变换方式对变速过程中混流泵稳定性的影响[J].农业工程学报,2024,40(24):49-58,10.基金项目
国家自然科学基金项目(52439006,52309118) （52439006,52309118）
