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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 uniformity of the concrete at the outlet of the nozzle, a physical model is established according to the structure of the nozzle of the nozzle. The mechanical model of the mixed fluid in the internal flow field is established according to the fluid dynamics equation. Field exit theoretical speed and theoretical pressure. Then, the liquid in the nozzle of the wet jet machine was modeled using Gambit software. Combined with CFD software Fluent, RNG turbulence model and Euler model in multiphase flow were used to simulate the gas-solid two-phase flow in the nozzle. The pressure, velocity, and phase volume fraction cloud maps. On this basis, the volume fraction of each phase in the outlet section of the mixed fluid was analyzed, and the uniformity of the air in the mixture was 93.88%. The results show that the theoretical value of the mixed fluid is close to the simulation value by comparing the theoretical value with the simulation value. The mixture of concrete and air is very uniform at the exit of the nozzle. The correctness of the simulation calculation is verified by the concrete injection test. The existing nozzle structure has certain rationality and provides the basis for the improvement and optimization of the nozzle structure in the future.