| As one of water-saving irrigation technologies, drip irrigation has many advantages such as water-saving, high efficiency, increasing yield, and improving crop quality, so that it has been emphasized by western developed countries all the time, and developed quickly in our country these ten years. Drip emitters are key functional parts in the drip irrigation system, whose performance and cost determine the operating costs and efficiencies of the entire drip irrigation system. Lots of studies have been made in aspects of hydraulic calculation, performance evaluation, use efficiency, and clog controlling, which supplied much guidance for how to improve the application and performance of drip emitters. However, the two-phase flow field in drip emitter is too complex to be characterized using analytical approach now.The text research on five models of three new types drip emitters which it was designed by ourselves, the technique of computational fluid dynamics (CFD) is used to complete liquid phase flow field and tracks of the particle simulations within drip emitters. As to the liquid phase flow field, there are five different turbulence models which include standard k-εmode1, RNG k-εmodel, Realizable k-εmodel, standard k-ωmodel, SST k-ωmodel, have been used to simulate the stream flow within the drip emitters. In the same case of the initial conditions and boundary conditions the expectation result of the standard k-ωmodel and SST k-ωmodel are better than the others, and moreover the expectation result of the standard k-ωmodel is close to the test result.This paper adopts the Particle-Track model to simulate the track of the particle. This model can reduce the computer memory and save time, simulate the complex process of the particle phase and use Lagrange method to reduce the false diffusion. The Random Particle-Track model simulate the turbulent diffusion. These simulation results are validated by the experiment of relationship with pressure and flux of the drip emitters.
|
PDF Full Text Request