混凝土喷射机喷嘴内混合流体流场均匀度研究

发布时间：2018-06-08 17:55

本文选题：混凝土湿喷机 + 喷嘴　；参考：《中南大学》2013年硕士论文

【摘要】：混凝土喷射机是一种广泛应用于喷锚支护领域的工程设备。但在施工时,喷射机存在回弹率高的问题。本文针对这一核心技术问题采用数值模拟仿真结合实验验证的方法,对喷射机喷嘴流场内混合流体的均匀度进行研究,得到混合流体(空气、速凝剂和混凝土)的成分均匀度和速度均匀度是影响混凝土喷射回弹率的主要因素。具体工作如下： 1、建立了喷射机喷嘴流场内混合流体的物理模型；在CFD仿真软件Fluent中建立了喷射机喷嘴流场内混合流体的数学模型,为混合流体进行数值模拟仿真提供依据； 2、应用上述的物理几何模型和数学模型,对喷射机喷嘴流场内混合流体的速度、压力以及湍流动能进行模拟仿真,得到速度场、压力场以及相体积分数分布规律； 3、采用RNG k-ε湍流模型,对不同结构参数下的喷射机喷嘴流场内混合流体进行数值模拟仿真,分析结构参数对混合流体均匀度的影响,得到喷射机喷嘴长径比、半锥角和进口入射角与混合流体均匀度的关系,并利用均匀试验设计得到三者之间的最优组合； 4、通过对不同工艺参数下的喷射机喷嘴流场进行数值模拟仿真,得到喷射机泵送量与空压机的风压对其混合均匀度的影响关系,找到了该喷射机喷嘴的最优空气压力,并得到了在本文分析模型的混凝土特性下该喷射机喷嘴的最大喷射能力； 5、喷射机喷嘴在不同空气压力与泵送量下进行喷射实验,结果表明通过提高混合流体的成分均匀度和速度均匀度,可以减少混凝土的回弹率。本文的研究结果可以指导喷射机喷嘴的设计和使用。
[Abstract]:The concrete ejector is a kind of engineering equipment which is widely used in the field of shotcrete and anchor support. But in construction, the ejector has the problem of high rebound rate. In this paper, a numerical simulation method combined with experimental verification is used to study the uniformity of the mixing fluid in the nozzle flow field of the injector, and the mixed fluid (air, air) is obtained. The composition uniformity and velocity uniformity of accelerator and concrete are the main factors affecting the rebound rate of concrete spray. The specific work is as follows: 1. The physical model of mixing fluid in jet nozzle flow field is established, and the mathematical model of mixing fluid in jet nozzle flow field is established in CFD simulation software fluent. It provides the basis for the numerical simulation of the mixed fluid. Secondly, the velocity, pressure and turbulent kinetic energy of the mixed fluid in the jet nozzle flow field are simulated by using the above physical geometry model and mathematical model, and the velocity field is obtained. The pressure field and the distribution of phase volume fraction. 3. Using RNG k- 蔚 turbulence model, the mixing fluid in the jet nozzle flow field under different structure parameters is simulated numerically, and the influence of structure parameters on the uniformity of mixing fluid is analyzed. The relations between the ratio of length to diameter, the half cone angle and the inlet angle of the jet nozzle and the uniformity of the mixing fluid are obtained. The optimal combination of the three is obtained by using uniform test design. 4. Through numerical simulation of jet nozzle flow field under different technological parameters, the influence of jet pump quantity and air pressure on mixing uniformity is obtained. The optimum air pressure of the jet nozzle is found, and the maximum injection capacity of the jet nozzle is obtained under the concrete characteristics of the model in this paper. The results show that the springback of concrete can be reduced by increasing the uniformity of composition and velocity of the mixed fluid. The results of this paper can be used to guide the design and use of jet nozzles.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU643

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