Optimization Design Research Of S-type Tube Valve Of Concrete Wet Spraying Machine Based On Pressure Loss

The concrete wet spraying machine, which is widely applied in Spray anchor bracing engineering field, is a type of special equipment, while S tube valve is one key component of the concrete pump. During the concrete wet spraying machine working process, S tube valve is docked with Concrete pumping cylinders alternately to loading and feeding concrete. Because the state of concrete flowing in S tube valve is complex solid-liquid two-phase flow, whether the design of S tube valve is reasonable will have directly influence on the pattern and pressure loss. Based on the relevant theories, the parameters and states of S tube valve are studied comprehensively, and then some conclusions and optimize ways, which are significant practice value and guidance significance, are obtained in this present thesis.The main contents in this present thesis are stated as follows:1. Based on the relevant theory on concrete pumping, the pressure loss during the concrete flowing in straight pipe, elbow pipe and taper pipe is calculated and analyzed, and then the formula of the total pump pressure required is deduced under the wet spraying machine working process. Furthermore, according to the characteristics of the two-phase of the concrete flowing in the S tube value, the two-fluid Euler equations are established to analyze the flowing characteristics in the turbulent model and drag coefficient model.2. The physical model and boundary conditions are modeled and applied sequentially, which are employed to simulate the concrete flowing in the S tube value, and then the flowing velocity, pressure and the turbulence distribution law are acquired. In order to describe the random position analytically in S tube valve, Polar coordinate modeling method in circular bending pipe is adopted in this present thesis, and then the pressure curve is drawn at different angels.3. According to the dimensional analysis" π theory", the parameters of S tube valve are simplified and optimized. Moreover, the numerical model is established and simulated successively under multiple loading conditions in the FLUENT software. And then the pressure loss when the concrete flowing in S tube valve is obtained, which is affected commonly by diameter, radius of curvature and the proportion of the horizontal length. In addition, the impact on the pressure loss, which is caused by different operating parameters such as concrete initial velocity, solid concentration and particle size, is considered and analyzed. Finally, the parameters optimize value of S tube valve is figured out in special range and the optimal parabolic equation for the structure design of S tube valve is deduced.4. Based on the experiment, the conclusion that the pressure loss is less when the concrete flows in the optimized S tube valve is verified. Furthermore, the influence on the pressure loss caused by solid concentration and volume is further verified. The maximum error between experimental data and numerical simulation result is less than10%.