Experimental Study On Hydraulic Perform-Ance And Water Distribution Of Micro Jet

Micro sprinkler irrigation has the advantages of saving water,saving labour and improving microclimate.It is a new type of micro sprinkler irrigation equipment.It has low cost,convenient construction and application,and has broad application prospects.The hydraulic performance and uniformity of water distribution are important factors affecting the quality of micro sprinkler irrigation,but the study is not deep enough.The factors affecting the hydraulic performance and uniformity of water distribution of micro jet belt are studied.It is of great value for the optimization design of micro jet belt irrigation system and the promotion of micro sprinkler irrigation technology in china.This article through micro sprinklinghose test of hydraulic performance and water distribution,analyzes the micro sprinklinghose pressure distribution and pressure flow relationship according to the basic theory of hydraulics and test results to determine the effect of micro spray water distribution factor was proposed to improve the optimization scheme of micro spray irrigation uniformity,reduce the cost of investment as the goal,has the following main conclusions:(1)the flow per unit length of the micro jet belt increases with the increase of pressure.The pressure and flow rate of the 32 micro jet belt accord with the power function,and the pressure of the 28 micro jet belt is approximately linear with the flow rate.The greater the pressure at the end of the head,the smaller the pressure at the end of the end of the head,the more uniform the loss of head.The pressure distribution along the micro jet belt is the first condition to study the water distribution along the micro jet belt.The pressure is gradually reduced by the head loss,but the values of the pressure decrease at the 5m interval are not the same.In the practical application of micro jet belt,the range of the initial pressure value and the length of the micro jet Belt should be carefully chosen to avoid excessive head loss.Within the suitable pressure range of the micro jet belt,the jet width of the micro jet belt increases with the increase of pressure.The spray amplitude of the 32 micro jet belt and the 28 micro jet belt is approximately linear with the pressure.(2)with the increase of injection angle,the range increases first and then decreases with the injection angle increasing.For the 32 mm micro jet belt,the maximum range can reach about 2.7m when the injection angle is 30 degrees.In designing the location of the jet hole,the distance between the spray holes and the location should be properly arranged so as to meet the requirements of irrigation water quantity and uniformity in different locations of the field.With the increase of single jet angle,the average intensity of sprinkler irrigation first decreased and then increased,and the area of humid area first increased and then decreased,and the area of humid area showed the opposite trend with the intensity of sprinkler irrigation.The pressure value has little influence on the area of wetting zone and the width of drying zone.When the injection angle is 30 degrees,the width of drying zone is the maximum,which can reach about 2.0m.With the increasing of the injection angle,the width of the drying area is similar to that of the range,and then increases first and then decreases.The width of the drying zone determines the proper distance between the micro jet belt and the crop.In order to ensure the uniformity of the micro jet irrigation,the spray holes should be well arranged.(3)micro spray with water distribution uniformity directly affects the effect of irrigation,water distribution uniformity and measurement point pressure value is closely related with the existence of the optimal operation pressure of spray water distribution is not uniform,the greater the pressure of water distribution is more uniform.In the micro jet pipe pressure is 23 kPa water distribution uniformity coefficient is maximum,along with micro jet direction,in order to make the whole micro spray spray with good uniformity,in the practical application should make micro sprinklinghose work pressure maintained at the optimal uniformity of the corresponding pressure value.(4)integrated water and fertilization conditions,along the length direction of micro sprinklinghose fertilizer concentration decreased gradually.The longer the micro jet belt,the greater the concentration difference between the head and the end.The concentration of fixed point fertilizer decreased gradually with time.Under the same amount of fertilizer,the change of the pressure value has little influence on the concentration of the fertilizer solution in the pipeline.The concentration of the fertilizer solution in the pipeline was consistent with the concentration of the fertilizer solution at the end of the fertilizer tank.