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| DOI：10.13522/j.cnki.ggps.2016.0262 |
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| Research on Drag Reduction of Irrigation Delivery Pipeline |
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CHEN Xueli, WEI Zhengying, MA Ruijia, MA Shengli, MA Chao
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State Key Lab for Manufacturing System Engineering, Xi’an Jiaotong University, Xi’an 710049, China
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| Abstract: |
| 【Objective】 Explore the drag reduction effect of riblet structure on the irrigation pipeline. 【Method】The drag reduction effect of the riblet in the turbulent flow was simulated by SA and RNG k-? turbulence model, and compared with the results of Bechert’s test, then the RNG k-? turbulence model was used to analyze the V-shaped riblet drag reduction at the scale of 0.1~1 mm for the irrigation pipeline, finally the LES turbulence model was used to explore the drag mechanism of the riblet structure. 【Result】 Compared with the SA turbulence model, the RNG k-? turbulence model had the smaller error compared with the Bechert’s test result, which was 4.6%, in other word, the RNG k-? turbulence model was more accurate. For a V-shaped riblet with the angle of 60°, when the riblet length was 0.5 mm, it had the best drag reduction effect on the irrigation pipeline, the drag reduction rate was 7.17%, corresponding to the dimensionless pitch s+ was 15.2, and dimensionless riblet size lg+ was 10. There were small vortices in the riblets that might be one of the causes of the drag reduction in the turbulence. 【Conclusion】 The best drag reduction effect of the V-shaped riblet with an angle of 60°for the irrigation pipelines was 7.17%. |
| Key words: irrigation pipeline; riblet drag reduction; numerical simulation; RNG k-? turbulence model |
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