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张春晋,孙西欢,李永业,张学琴.螺旋流起旋器内部流场水力特性数值模拟与验证[J].农业工程学报,2018,34(1):53-62.DOI:10.11975/j.issn.1002-6819.2018.01.08
螺旋流起旋器内部流场水力特性数值模拟与验证
投稿时间:2017-07-15  修订日期:2017-11-12
中文关键词:  灌溉  流场  数值分析  低压管道  起旋器  螺旋流  起旋效率  导叶
基金项目:国家自然科学基金项目(51179116,50579044,51109155);山西省自然科学基金项目(2015011067,201701D221137)
作者单位
张春晋 1.太原理工大学水利科学与工程学院太原 030024
 
孙西欢 1.太原理工大学水利科学与工程学院太原 030024
2. 晋中学院晋中 030600
 
李永业 1.太原理工大学水利科学与工程学院太原 030024
 
张学琴 3. 章丘黄河河务局济南 250200
 
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中文摘要:为了有效解决低压平直管道在田间长距离调水中泥沙淤积问题,该文设计了一种螺旋流起旋装置:螺旋流起旋器。与传统的起旋装置相比,螺旋流起旋器的导叶被固定在与管道保持同心状态的料筒外壁面。该文基于RNG k-ε湍流模型,采用Fluent 12.0对不同导叶长度条件下螺旋流起旋器内部流场水力特性进行了非定常数值模拟,并将模拟值与试验值对比分析,结果表明:螺旋流起旋器内部流场模拟值与试验值基本吻合,且流速场和压力场的最大相对误差分别不超过6.4%和1.3%,进一步表明采用Fluent数值模拟求解螺旋流起旋器内部流场是可行的;随着导叶长度的增加,螺旋流起旋器下游流场的轴向流速的影响区域将逐渐减小,而径向流速、周向流速及涡量的影响区域将逐渐增大;螺旋流起旋器能耗损失与起旋效率均随着导叶长度的增加呈现出增大的变化趋势;螺旋流起旋器内部流场涡量主要分布于料筒近壁面、导叶近壁面及螺旋流起旋器的下游流场。该研究不仅为螺旋流起旋器的设计与优化提供了参考依据,同时还为进一步完善管道螺旋流长距离输固理论提供了坚实的理论基础。
Zhang Chunjin,Sun Xihuan,Li Yongye,Zhang Xueqin.Numerical simulation and verification of hydraulic characteristics of internal flow field in spiral flow generator[J].Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE),2018,34(1):53-62.DOI:10.11975/j.issn.1002-6819.2018.01.08
Numerical simulation and verification of hydraulic characteristics of internal flow field in spiral flow generator
Author NameAffiliation
Zhang Chunjin 1. School of Hydro Science & Engineering, Taiyuan University of Technology, Taiyuan 030024, China
 
Sun Xihuan 1. School of Hydro Science & Engineering, Taiyuan University of Technology, Taiyuan 030024, China
2. Jinzhong University, Jinzhong 030600, China
 
Li Yongye 1. School of Hydro Science & Engineering, Taiyuan University of Technology, Taiyuan 030024, China
 
Zhang Xueqin 3. Zhangqiu Yellow River Bureau, Jinan 250200, China
 
Key words:irrigation  flow fields  numerical analysis  low-pressure pipeline  generator  spiral flow  spiral generating efficiency  guide vane
Abstract: Low-pressure straight pipeline was usually used to transport sediment-laden flow in the traditional field irrigation. Sediment deposition often triggered pipe blockage and affected normal run of the fluid-conveying pipeline. In order to effectively solve the problem of pipe blockage caused by sediment deposition during a long-distance inter-field water transfer process of the low-pressure straight pipeline, this paper designed a kind of spiral flow generating device: A hydro-spiral generator. Compared with the traditional spiral flow generating device, the guide vanes were fixed on the exterior surface of the barrel which always maintained concentric with the fluid-conveying pipeline. The hydro-spiral generator works by producing reverse resistance and vertical lift on the fluid under the action of the guide vanes, and forming a stable velocity circulation and a spiral flow of uniform vortex strength within the pipeline. The supports made it more flexible to arrange the hydro-spiral generator at any position and greatly enhanced the intensity and scope of continuous generating spiral, which was significant in improving irrigation efficiency of sediment-laden flow in the field irrigation. In order to rationally design structural parameters of the hydro-spiral generator, a geometrical model of the hydro-spiral generator with different guide vane lengths was established by using Auto CAD (computer aided design) software. Based on RNG k-ε turbulent model and PISO algorithm, hydraulic characteristics such as the axial velocity, the radial velocity, the circumferential velocity, the pressure and the vorticity magnitude inside the hydro-spiral generator having different guide vane lengths were investigated numerically with three-dimensional unsteady calculation by using the commercial Fluent 12.0 software. At the same time, the spiral generating efficiency was deduced to further analyze the effects of the guide vane length on spiral generating capability. The hydraulic characteristics of internal flow field were studied by using model tests inside the hydro-spiral generators with guide vane lengths of 0.025, 0.050, 0.075, and 0.100 m respectively. The barrel was 0.1 m long with an outside diameter of 0.05 m, and structure parameters of the guide vane were 0.01 m for height and 30° for placement angle. The seven-port point gauge, pressure sensors and standard dynamic pressure collection box were used to measure flow velocity and pressure distributions at the typical sections, and the simulated values were compared with the experimental values. The results showed that the simulated values of internal flow field in the hydro-spiral generator were in good agreement with the experimental values , and the maximum relative errors of the flow velocity field and the pressure field did not exceed 6.4% and 1.3% respectively, which further indicated that it was feasible for solving hydraulic characteristics of internal flow field inside the hydro-spiral generator using the commercial Fluent 12.0 software. As the length of the guide vane increased, the affected areas of the axial velocity gradually decreased, while the affected areas of the radial velocity, the circumferential velocity and the vorticity magnitude gradually increased at the downstream flow field of the hydro-spiral generator. With the increase of guide vane length, the energy losses caused by the hydro-spiral generator showed an increasing trend. There was an obvious low pressure zone at the downstream flow field of the hydro-spiral generator, and then the pressure again rose along the downstream direction of the fluid-conveying pipeline. The vorticity magnitude of the hydro-spiral generator was mainly distributed in the near-wall areas of the barrel near the entrance to the cyclical slit flow, the near-wall areas of the guide vanes and the downstream flow field of the hydro-spiral generator. As the increase of guide vane length, the spiral generating efficiency of the hydro-spiral generator gradually increased. The study of this paper not only provides references for further designation and optimization of the hydro-spiral generator, but also improves comprehensive theoretical basis for further perfecting the theories of long-distance solid transportation and the technologies of spiral flow solid transportation.
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