Numerical Simulation Of Infiltration Characteristics In Film Slit Irrigation And Research On Its Rectified Model

The paper about the technical route that theoretical analysis of the laboratory test combines with numerical simulation and that depends mainly on numerical simulation and experimental verification. Soil water movement model is also established based on the theory of soil moisture movement and water distribution of wetted body and infiltrating regulation studies under film slit irrigation. In the end, the average simplifies infiltration depth model of film slit is established and verified. The following results are concluded through the above research:(1)Two dimensional soil moisture movement model and boundary condition are established on the basis of the equation of soil hydrodynamics. And the accumulative infiltration capacity and moisture distribution of soil wetted body are obtained by usingSWMS-3D software. Also, cumulative infiltrating capacity of the film slit and soil moisture content is measured through 8-group laboratory experiments of film slit irrigation. The comparison between analog value and measured value are conducted, the result of which indicated that the analog value coincided with the measured value on the whole; This shows that the model and algorithm proposed in the paper can be used in the analysis of characteristics of film slit irrigation and wetted body.(2)The infiltrating feature of film slit irrigation and water distribution of wetted body are simulated by using the model established under different irrigation technical elements. It concludes that soil texture and soil bulk density affectes cumulative infiltrating capacity and moisture content of soil wetted body greater, which similarly are influenced by film slit width. And Cumulative infiltrating capacity and moisture content of wetted body increased as the width increased. The impact of initial water content, film width and film slit width on accumulative infiltrating capacity and moisture content of soil wetted body are not significant under other conditions that are constant. In addition to the above, we analyzes the influence of slotted rate and width of film slit on the average of infiltration depth and makes the conclusion that slotts rate and width are important factors of the average infiltration depth under the control of film slit. The average infiltration depth increases remarkably as slotted rate increased, however, increases as the width decreased.(3) The SWMS-3D is used to simulate and analyze the relationship between the average infiltration depth and time. The result indicates that the curve of their relationship conformes to Kostiakov model, which is utilized to fit and analyze the curve of the relationship between the average infiltration depth and time under the control of film silt. The conclusion is that the coefficient and exponent of infiltration varies with soil texture, volume weight, slottes rate and width. Therefore, the average simplifies infiltration depth model in common use is established in case of different soil textures and volume weights: Z=A'(ρ/d^0.18)t^B'-0.21ρ 0.21ρThen the simplifies model is verified through laboratory experiments. The result indicates that the deviation between the calculation of simulation and measures value was relatively small, which proves that the model could describe effectively the infiltration law of film slit.