水下航行体空化流动与压力脉动特性研究

发布时间：2018-02-02 05:31

本文关键词： 水下航行体空化流动通气空化水洞实验压力脉动旋涡结构　出处：《哈尔滨工业大学》2017年博士论文　论文类型：学位论文

【摘要】：水下航行体空化流动是一种复杂的气液多相湍流流动,包含了空泡的生长、断裂、脱落、溃灭等多种非定常流动过程,涉及可压缩、旋涡运动和大尺度流动分离等复杂流动现象。对水下航行体空化流动过程中空泡形态的非定常特性及压力脉动特性的研究有助于对空化流动规律的掌握,并关系到水下武器、航空航天等领域内关键技术问题的解决,具有重要的理论意义和工程价值。本文采用水洞实验与数值模拟相结合的方法,针对水下航行体空化流动问题,开展了绕航行体模型自然空化与通气空化流动过程中空泡形态的非定常演变特性及压力脉动特性的研究,主要研究内容和成果如下:建立了水下航行体自然空化和通气空化水洞实验的多场同步测量实验方法。该方法把高速摄像系统、压力测量系统和通气系统组建成一个整体,实现了水洞实验过程中自然空化或通气空化过程空泡形态演变和压力脉动变化过程的同步采集,并对航行体肩部空泡形态和航行体表面压力脉动的非定常流动特性进行同步分析。基于多场同步测量方法,开展了自然空泡和通气空泡形态演变及其诱导表面压力脉动特性研究,掌握了不同空化数下自然空泡与通气空泡断裂、脱落、溃灭过程诱导的压力脉动规律及频域特性。通过对航行体模型空化过程空泡形态演变和压力脉动同步测量数据分析,获得了自然空泡与通气空泡脱落方式、脱落频率特征和航行体表面压力脉动变化规律。开展了通气启动和通气停止过程非定常云状空泡发展与压力脉动特性研究,掌握了通气启动和停止后空泡形态演变和压力脉动变化规律。通过对通气启动后通气空泡形态演变过程研究,掌握通气启动后空泡形态演变过程和通气空泡发展过程航行体表面压力随通气率变化规律;针对通气空泡停止通气后,获得了空泡溃灭演变过程及空泡溃灭诱导的压力脉动特性。基于均质平衡流模型,发展了基于标准k-ε的滤波器湍流模型,建立了非定常通气空化多相流动的三维数值模拟方法。以水洞实验数据为基准,通过实验过程空泡形态的演变过程及航行体表面压力脉动特征,验证了基于标准k-ε的滤波器湍流模型对非定常通气空化流动过程中空泡形态演变、压力脉动特性及流场细节预示的有效性。基于建立的非定常通气空化三维数值模拟方法,开展非定常通气条件空化流动数值模拟研究。分析了通气空泡的演变过程对航行体周围流场结构的影响及通气空化的旋涡运动特性,掌握了非定常通气空化过程中空泡发展、断裂、脱落与速度矢量、流体动力、旋涡结构及涡量传输的关系,揭示了通气空化形态演变过程及其诱导压力脉动的机理。
[Abstract]:Cavitation flow of underwater vehicle is a kind of complicated gas-liquid multiphase turbulent flow, which includes cavitation growth, fracture, shedding, collapse and other unsteady flow processes, involving compressible flow. The study on the unsteady characteristics of cavitation and pressure pulsation in cavitation flow of underwater vehicle is helpful to the understanding of cavitation flow law. It is of great theoretical significance and engineering value to solve the key technical problems in the field of underwater weapon, aerospace and so on. In this paper, the method of combination of water tunnel experiment and numerical simulation is adopted. In order to solve the cavitation flow problem of underwater vehicle, the unsteady evolution characteristics and pressure pulsation characteristics of cavitation flow in natural cavitation and aerated cavitation flow around the vehicle model were studied. The main research contents and results are as follows: a multi-field synchronous measurement method for underwater vehicle natural cavitation and aeration water tunnel experiments is established. The pressure measurement system and the ventilation system are set up as a whole to realize the synchronous collection of cavitation morphology and pressure fluctuation in the process of natural cavitation or aeration cavitation in the process of water tunnel experiment. The unsteady flow characteristics of the surface pressure pulsation and the shape of the cavitation on the surface of the navigation body are analyzed synchronously, based on the method of multi-field synchronous measurement. The morphological evolution of natural cavitation and aerated cavitation and the characteristics of induced surface pressure pulsation were studied. The fracture and shedding of natural cavitation and aerated cavitation were mastered under different cavitation numbers. By analyzing the data of cavitation morphology evolution and pressure pulsation during cavitation process, the natural cavitation and aerated cavitation shedding mode were obtained. The characteristics of falling off frequency and pressure pulsation on the surface of the vehicle were studied. The development of unsteady cloud cavitation and pressure pulsation in the process of ventilation start-up and ventilation stop were studied. The changes of cavitation morphology and pressure fluctuation after ventilation start and stop were studied. Understand the evolution process of cavitation morphology and aeration cavitation development process after ventilation start, and the change of surface pressure with aeration rate in the process of aeration cavitation development; The evolution process of cavitation collapse and pressure pulsation induced by bubble collapse were obtained. Based on the homogeneous equilibrium flow model, the filter turbulence model based on standard k- 蔚 was developed. A three-dimensional numerical simulation method for unsteady aerated cavitation multiphase flow is established. Based on the experimental data of water tunnel, the evolution process of cavitation morphology and the characteristics of pressure pulsation on the surface of the vehicle are studied. The filter turbulence model based on standard k- 蔚 is used to verify the evolution of cavitation morphology in unsteady ventilated cavitation flow. The effectiveness of pressure fluctuation characteristics and flow field details prediction. Based on the established three-dimensional numerical simulation method of unsteady ventilation cavitation. The numerical simulation of cavitation flow under unsteady ventilation conditions was carried out. The effects of the evolution of aerated cavitation on the flow field structure around the aeration body and the vortex motion characteristics of aeration cavitation were analyzed. The relationship between cavitation development, fracture, shedding and velocity vector, hydrodynamic force, vortex structure and vorticity transmission during unsteady ventilation cavitation is mastered. The evolution of aeration cavitation morphology and the mechanism of induced pressure pulsation are revealed.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O35

【相似文献】