摘要
为了研究湿喷机喷嘴出口混凝土的均匀程度,根据湿喷机喷嘴流场的结构建立物理模型,再根据流体动力学方程建立混合流体在喷头内部流场中的力学模型,得到混合流体在喷嘴流场出口的理论速度和理论压力。然后利用Gambit软件对湿喷机喷嘴内流体进行三维建模,结合CFD软件Fluent选用RNG湍流模型与多相流中的欧拉模型,对喷嘴内气固两相流进行仿真计算,得到喷嘴内流体的压力、速度云图和相体积分数云图。在此基础上分析混合流体在出口截面上各相的体积分数,得到了混合物中空气的均匀度为93.88%。研究结果表明:通过将理论值与仿真值进行对比,发现混合流体的理论值与仿真值较为接近;在喷嘴出口处混凝土和空气混合的很均匀;通过混凝土喷射试验验证了仿真计算的正确性,且现有的喷嘴结构具有一定的合理性,并为今后喷嘴结构的改进与优化提供依据。
In order to study the degree of homogeneity of concrete in the exit of wet spraying machine nozzle, this paper first established the physical model according to the structure of wet spraying machine nozzle flow field, and then established the mechanical model of mixed fluid in the internal flow field of nozzle according to the fluid dynamics equations to get the theoretical velocity and pressure of mixed fluid in flow field of nozzle. Through Gambit , the three dimensional model of fluid in the concrete spraying machine＇s nozzle was set up ,and with the CFD software Fluent, the turbulence model RNG and the Eulerian model in multiphase flow were selected to perform simulating calculation on the flow field of gas-solid two-phase in the nozzle. The fluid~ s contour about pressure, velocity and phase volume fraction in the nozzle were obtained. On this basis this paper analyzed each phase＇s volume fraction of the mixed fluid in the outlet section and obtained the air＇s uniformity in the mixture which was 93.88%. The result of simulating shows that the theoretical value of mixed fluid is close to the simulation values. Besides it, the concrete at the exit of the nozzle is mixed with air very well. Finally the test of the concrete jet verifies the correctness of the simulation calculation, and the existing structure of nozzle shows certain rationality, which provides a theoretical basis for future improvement and optimization. 3 tabs, 10 figs, 12 refs.
出处
《长安大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2015年第2期145-151,共7页
Journal of Chang’an University(Natural Science Edition)
基金
长沙市重大专项(K1203108-11)
关键词
机械工程
湿喷机
喷嘴
流场分析
均匀度
mechanical engineering
concrete spraying machine
nozzle
flow field analysis
uni-formity
