Numerical Simulation Of Low-Pressure Pipe Irrigation Forebay Self-Discharge Desilting Basin Flow Field

Sediment problem becomes one of the most important factors of hindering agricultural production.Sediment deposition make the canal head's ability of taking water and water carrying capability decreasing,farmland desertification.Threatening the agricultural production.There are different ways to solve the problem.The traditional way is to use the large desilting basin to deposite the sediment,but this way has many disadvantages.The tendency is changing the concentrated way to dispersion way,transporting the sediments for long distance to the irrigation district downstream,using small field desilting basin to deal with the sediments,making the sediments treatment high efficiency and low cost.The water resources scarcity make the water-saving irrigation a tendency of the agricultural production.Low-pressure pipe irrigation economize on water and energy,save the cultivated,has high adaptability. Low-pressure pipe irrigation forebay self-discharge desilting basin,as one form of the small field desilting basin,has agood prospect.According to the disadvantages of large desilting basin,point out that changing the concentrated way to dispersion way to treat the silt problem.Further generalization of the low-pressure pipe irrigation forebay self-discharge desilting basin needs more researches,considering that,this paper studies on velocity distribution pattern of field lateral,which is joined by the desilting basin,providing evidence for inlet velocity of the desilting basin. Most of the calculation of the channal velocity distribution pattern us to use empirical formulas,so the calculation theory needs further exploration.By means of theoretical derivation,we get a new method to calculate the vertical distribution of velocity,is a new idea for correlation theory.Based on above work,this paper make numerical simulation on flow field of low-pressure pipe irrigation forebay self-discharge desilting basin in different forms research on related design parameters of the desilting basin,such as the number of the adjusting–flow board,the position of the adjusting–flow board,the bottom slope of the desilting basin,finding the best form of the desilting basin.The most important feature of the low-pressure pipe irrigation forebay self-discharge desilting basin is automatic sediment ejection,avoiding artificial silteliminating or mechanical dredging.To achieve the goal,the most important essential is to make the sediment excretion without external force but sediment transport discharge.Depending on the water gravity,the sediment gravity and the coriolis force,making the sediment self-discharge from the desilting basin.Based on the result of the numerical simulation,we get that with the flushing flow rate,the flow velocity in desilting basin could reach the critical flow velocity for incipient motion.The low-pressure pipe irrigation forebay self-discharge desilting basin is feasible.