Causes of Different Performance of turbulent Models in Simulation of drip emitters outflow

Document Type : Research Paper

Authors

1 Shahrood University of Technology

2 Department of Water and Soil, Faculty of Agriculture, Shahrood University of technology, Shahrood, Iran.

Abstract

The emitter is a device used to dissipate pressure and to discharge water at a constant rate when pressurized water flows through its narrow and long path channels, hence emitter is the key component of the drip irrigation system. On the other hand, production of a suitable emitter is expensive and time–consuming. The use of computational fluid dynamics (CFD) can be a useful tool for reducing the time and cost of manufacturing of drip emitters. For this purpose, in present study three different types of drip emitters (with different channel geometry) were chosen and their structural parameters are determined using SEM. Rate of discharge of emitters were simulated by 4 turbulence models (standard k- ε ، RNG K-ε، K-ε Realizable، standard k-ω) and Laminar model compared with experimental discharge. Results showed that on the whole there was generally good agreement between the experimental results and those obtained by different turbulent and laminar models. But among the studied models, results of standard k- ω and standard k- ε had the best and the worst agreement with experimental results, respectively. So that, the mean NRMSE of three emitters for standard k-ε and standard k-ω models was determined 7.57 and 3.56 percent, respectively. As well as with regards to low Reynolds number, the laminar model also presented good results.

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Main Subjects

References

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Iranian Journal of Soil and Water Research
Volume 49, Issue 4
July and August 2018
Pages 853-863

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