液力减速器空化特征信号量化分析方法与验证  

Quantitative analysis method and verification of cavitation characteristic signal of hydraulic retarder

作　　者：董亮[1] 刘嘉伟 刘厚林[1] 肖佳伟[1] 赵宇琪[1] 

机构地区：[1]江苏大学流体机械工程技术研究中心,镇江212013

出　　处：《农业工程学报》2017年第22期53-60,共8页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金(51509111);中国博士后科学基金资助项目(2017M611721);西华大学流体及动力机械教育部重点实验室开放课题资助项目(szjj2017-094);江苏高校优势学科建设工程资助项目(PAPD)

摘　　要：空化监测阈值的确定是对液力减速器空化状态判别的关键环节。为准确量化液力减速器空化信号特征阈值,搭建了扭矩、振动、噪声、压力脉动和高速摄影的同步采集试验台。并在引入宽频带振动加速度和宽频带噪声声压级的基础上的,采用对每种工况计算其均值序列的原则对叶片倾角为0°的液力减速器的振动、噪声和压力脉动的空化特征信号进行了量化分析,确定了振动、噪声和压力脉动信号及其空化特征频带内的阈值。振动加速度级2 000~3 000 Hz频带阈值为94.5 d B,4 000~5 000 Hz频带阈值为89 d B。噪声声压级2 000~4 000 Hz频带内阈值为97 d B;5 000~6 400 Hz频带内阈值为78 d B;4APF处比值1.9,BPF处比值2.3。为了验证该文所建立量化分析方法的有效性,以叶片倾角为15°的液力减速器为研究对象,采用该文所提出的阈值确定方法对其空化状态进行评判,验证工况A(初始压力0.01 MPa)和B(初始压力0.03 MPa)任一特征频带上的振动噪声均大于相应阈值,判断工况A和B发生了空化;验证工况C(初始压力0.06 MPa)小于阈值,未发生空化。并通过高速摄影试验进行验证,验证工况A和B出现气泡,验证工况C未观测到气泡。结果表明,该文所提出的阈值确定方法能够准确的区分出液力减速器的空化状态。For accurately quantitatively analyzing characteristics threshold of hydraulic retarder cavitation signal and providing a theoretical basis for the structural optimization of hydraulic retarder and avoiding cavitation resulting in the decrease of braking capacity, a test rig is set, which can collect vibration, noise and pressure pulsation signal synchronously. In the test system, different from the original medium, the medium is clear water which does not change the initial conditions of cavitation and is more conducive to observe the development process of cavitation. In addition, clear water is easy to be replaced, so that the test difficulty is reduced. First, we test the external characteristics and conduct the signal acquisition. The pressure in reducer casing is maintained at 0.1 MPa by booster pump, and the drive motor runs at 800, 900, 1 000, 1 100 and 1 200 r/min respectively. Then the high-speed photography is carried out, and the acquisition of rotation rate, torque, temperature, pressure, noise and vibration acceleration signals is performed, followed by a cavitation performance test and its relevant signal acquisition. Next, pressure inside the chamber is reduced to 0.08, 0.06, 0.04, 0.03, 0.02 and 0.01 MPa respectively. Under these 6 different pressure conditions, the experiment steps were the same as those in 0.1 MPa condition. On the base of broadband vibration acceleration and broadband noise level, the principle of calculating the mean sequence of each working condition is used to analyze vibration and noise of hydraulic retarder of 0° blade dip angle quantitatively, as well as the cavitation characteristics signals of pressure fluctuation. Accordingly, the vibration, noise and pressure pulsation signal and the cavitation threshold in characteristic frequency band are determined. In order to facilitate the study of cavitation development degree under the working conditions, this paper introduces the concept of “relative torque” and “change rate” which can ease the difficult of quantifi

关 键 词：振动 噪声 信号分析 液力减速器 空化 压力脉动 

分 类 号：TH132.46[机械工程—机械制造及自动化]