受限空间强湍流射流流场流动特性基础研究

High-pressure waterjet technology, as a new widely applied technology using in mechanical processing, could cut almost all brittleness, plasticity, elastic, and composite material. However, cutting section irregular features limits its application in fine mechanical processing field. At present, in order to understand the cutting section irregular features’ mechanism and characteristics, researches on it nearly analyzed from the perspective direction of the material breakage characteristic, nearly ignored the high-pressure waterjet flow characteristic. Depending on understanding the formation of irregular features in cutting process by using the perspective of fluid mechanics, double-side wall confinements space model, similar with cutting process, has been employed to study the high-pressure turbulent waterjet cutting flow process flow flied. Depending on experimental and numerical simulation results, turbulent statistical theory analysis method, vortex motion analysis method and proper orthogonal decomposition (POD) coherent structure analysis method has been employed to systematically analyze flow characteristics influenced by confined height, Reynolds number, wall surface roughness and pressure fluctuation within the double-side wall confinements space high-pressure turbulent waterjet. Based on high-pressure turbulent waterjet flow field theory in double-side wall confined space, the formation mechanism of cutting section irregular features by high-pressure turbulent waterjet cutting can be studied combined with analysis of material breakage features, which maybe provide theoretical support for high-pressure waterjet cutting technology applied in the field of fine processing.

高压水射流技术作为一种新兴技术应用广泛，在机械加工领域高压水射流几乎能切割所有脆性、塑性、弹性及复合材料，但切割断面形貌的不规则特性限制了其应用于机械精细加工领域。目前，对切割断面形貌的研究多从材料破碎特性方向入手分析形貌的形成规律。本课题拟以类似射流切割流动的双壁面受限空间为研究对象，以受限空间射流流动特性研究为切入点，通过实验研究和数值模拟，利用湍流统计理论分析方法、涡运动分析方法和POD拟序结构分析方法系统分析受限空间内强湍流射流流动特性随受限空间宽度、雷诺数、壁面粗糙度和压力脉动的影响规律，建立受限空间内强湍流射流流动理论，为从流体力学流动特性入手研究断面形貌特性形成机制奠定理论基础；根据受限空间内强湍流射流流动特性规律，结合材料破碎特性分析射流切割断面不规则形貌的形成机制，为高压水射流切割技术应用于精细加工提供了理论支撑。

在机械加工领域高压水射流几乎能切割所有脆性、塑性、弹性及复合材料，但切割断面形貌的不规则特性限制了其应用于机械精细加工领域。本项目以高压水射流断面形成的双壁面受限空间为研究对象，首先通过实验研究和数值模拟系统分析受限空间内强湍流射流流动特性随受限空间宽度、雷诺数和压力脉动的影响规律，并对受限空间内流场特性进行深入挖掘和探讨，初步建立了受限空间内强湍流射流流动理论；同时利用高压水射流切割不同种类材料，分析材料断面形貌特征及分布影响规律；在上述研究基础上，结合材料破碎特性分析射流切割断面不规则形貌的形成机制，建立了相应的材料不规则形貌形成规律，为高压水射流切割技术应用于精细加工提供基础理论支撑。.本项目实施以来，发表SCI/EI论文6篇，申请发明专利2项，授权专利3项，项目负责人依托本项目前期研究成果申请成功国家博士后特别资助项目和重庆市基础科学与前沿技术研究计划一般项目。