高压气体微孔射流堆积粉料的破散性试验及参数研究

发布时间：2018-11-07 11:14

【摘要】：高压气体微孔射流冲击技术已广泛应用在切割、掘土、引射喷雾防尘、注浆技术等工程领域。立式强力混合机对粉料具有较好的混匀效果,但搅拌桨叶受粉料的冲击及摩擦阻力作用极易磨损,为改善堆积粉料的破散性和提高桨叶的使用寿命,将射流冲击技术应用于通气桨叶对堆积粉料破散过程。本文结合数值模拟和试验研究两种方式,对影响高压气体射流冲击效果的参数进行系统研究,可为射流冲击技术实现在球团堆积粉体领域的应用提供理论支持及技术指导。根据射流冲击的流体动力学原理,分析单股、多股及旋转高压气体微孔射流冲击的流场特性,重点研究射流的流场结构、轴线速度相似性分布规律,掌握不同条件下射流冲击过程的特性规律,并推导出圆断面射流主体段和初始段的速度及流量的关系式,为工程应用计算提供指导。开展了射流冲击参数试验。测定堆积粉粒体的相关物性,得到孔隙率、压缩度、外摩擦系数、内摩擦角和抗剪强度。物性参数试验可为数值模拟提供准确的输入参数,同时为进行射流冲击破散性试验提供相关依据。开展了射流冲击形态和喷距试验。确定不同喷嘴类型在不同射流压强下的最佳喷距,为数值模拟和试验研究提供思路和方案。采用气固Eulerian多相流建立九孔喷嘴三维仿真模型,选择Realizableκ-ε湍流模型对射流冲击粉粒体过程进行数值模拟。研究分析了射流压强、冲击时间、粉料粒径、喷嘴类型和喷距等参数对射流冲击的影响,得到较优的工况参数。开展了射流冲击堆积粉料破散性参数试验。研究不同射流压强、冲击时间、喷嘴类型和喷距等射流参数下冲击堆积粉料的破散性效果。比较分析其孔口深度、切割宽度、破散体积的形成原因,得到冲击效果最佳的一组参数,验证了数值模拟的可靠性。
[Abstract]:High pressure gas microporous jet impingement technology has been widely used in the fields of cutting, digging, ejecting spray and dustproof, grouting technology and so on. The vertical strong mixer has better mixing effect on powder, but the impingement and friction resistance of agitating blade are easy to wear, in order to improve the breaking property of powder and the service life of blade, The jet impingement technique was applied to the process of breaking and dispersing of aerated propeller blades. In this paper, the parameters affecting the impingement effect of high pressure gas jet are systematically studied by numerical simulation and experimental study, which can provide theoretical support and technical guidance for the application of jet impingement technology in pelletizing powder field. According to the hydrodynamic principle of jet impingement, the flow field characteristics of single-strand, multi-strand and rotating high-pressure gas micro-hole jet impingement are analyzed. The characteristic law of jet impingement process under different conditions is grasped, and the relationship between velocity and flow of jet body and initial section of circular section is deduced, which provides guidance for engineering application calculation. The jet impingement parameter test was carried out. The porosity, compression degree, external friction coefficient, internal friction angle and shear strength were obtained. The physical parameter test can provide accurate input parameters for numerical simulation and provide relevant basis for jet impinging and breaking test. The jet impingement morphology and jet distance test were carried out. The optimum jet distance of different nozzle types under different jet pressure is determined, which provides ideas and schemes for numerical simulation and experimental study. Three-dimensional simulation model of nine-hole nozzle was established by gas-solid Eulerian multiphase flow, and Realizable 魏-蔚 turbulence model was selected to simulate the jet impingement process. The effects of jet pressure, impact time, particle size, nozzle type and injection distance on jet impingement were studied and the optimal operating conditions were obtained. The breakage parameter test of jet impingement piling powder was carried out. The breakage effect of impingement piling powder under different jet pressure, impact time, nozzle type and jet distance was studied. By comparing and analyzing the formation reasons of hole depth, cutting width and breaking volume, a set of parameters with the best impact effect is obtained, and the reliability of the numerical simulation is verified.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD92

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