An indoor experiment with a fixed spray plate sprinkler(FSPS) of 36-grooved plate D3000 was conducted to evaluate the discharge-pressure relationship,wetted diameter,effective width,and water application rate in this ...An indoor experiment with a fixed spray plate sprinkler(FSPS) of 36-grooved plate D3000 was conducted to evaluate the discharge-pressure relationship,wetted diameter,effective width,and water application rate in this research.In addition,a field experiment with a center pivot system equipped with the same measured FSPS was carried out to investigate the radial and circular uniformity under different cycle times and settings of the percent-timer.A package of nozzles numbering from #9(1.79 mm) to #33(6.55 mm) was tested with a nozzle elevation of 1.2 m and a 20-psi pressure regulator.The results showed that the wetted diameter and average application rate increased with nozzle size,but the effective wetted width and peak instantaneous application rate had no significant relationship with nozzle size.The simulated application rate of the center pivot system using the measured water distribution data of single FSPS was in good agreement with the measured result,which verified that the improved measurement procedure and modified nozzle sizing equation of the D3000 sprayhead in this paper were correct.Reducing the percent-time cycle time from 60 s to 40 s resulted in a slight increase in the radial uniformity coefficients,with an average of 1.09% to 1.17%,while there was no significant influence on the circular uniformity coefficients.展开更多
One way to adapt to the trend towards low-energy and to improve the hydraulic performance of the impact sprinkler under a low pressure condition is by means of a fixed water dispersion device.A fixed dispersion device...One way to adapt to the trend towards low-energy and to improve the hydraulic performance of the impact sprinkler under a low pressure condition is by means of a fixed water dispersion device.A fixed dispersion device disperses jet flow from the nozzle continuously.The shape of the tip,impact angle(θ),diameter(D),and depth in the jet flow(d)have significant influence on the hydraulic performance.In this study,the hydraulic performance characteristics of impact sprinkler as affected by the fixed water dispersion device were studied under indoor conditions.Radial water distributions from the sprinkler were obtained by experiments for the fixed water dispersion devices.MATLAB was used to transform the radial data into net data,and the uniformities were simulated in a square layout from 1 to 2 times the range(R).The droplet size distributions from the fixed water dispersion devices were measured by a laser precipitation monitor(LPM).Results showed that the range increased with the increase of pressure,and the sprinkler with type C_(2) produced a rectangular-shaped water distribution pattern,while the range was maintained.A maximum uniformity of 71.56%,75.56%,77.23%,73.32%,78.88%and 86.67%was found for types A1,B1,C1,A2,B2,and C_(2),respectively under a pressure of 200 kPa.The uniformity from the sprinkler using type C_(2) surpassed 80%,while type C1 fell below.Droplet sizes from type C_(2) was best,and the mean droplet diameter decreased with the increase of pressure.Hence,type C_(2) can be selected for further optimization of the design features to improve the hydraulic performance of the impact sprinkler under low pressure conditions.展开更多
基金supported by the China Key Technological Special Project of National Tenth Five-Year Plan (Grant No.2002AA2Z4161)Program for Changjiang Scholars and Innovative Research Team in University (Grant No.IRT0657)Program for Beijing Key Subject of Hydrology and Water Resources
文摘An indoor experiment with a fixed spray plate sprinkler(FSPS) of 36-grooved plate D3000 was conducted to evaluate the discharge-pressure relationship,wetted diameter,effective width,and water application rate in this research.In addition,a field experiment with a center pivot system equipped with the same measured FSPS was carried out to investigate the radial and circular uniformity under different cycle times and settings of the percent-timer.A package of nozzles numbering from #9(1.79 mm) to #33(6.55 mm) was tested with a nozzle elevation of 1.2 m and a 20-psi pressure regulator.The results showed that the wetted diameter and average application rate increased with nozzle size,but the effective wetted width and peak instantaneous application rate had no significant relationship with nozzle size.The simulated application rate of the center pivot system using the measured water distribution data of single FSPS was in good agreement with the measured result,which verified that the improved measurement procedure and modified nozzle sizing equation of the D3000 sprayhead in this paper were correct.Reducing the percent-time cycle time from 60 s to 40 s resulted in a slight increase in the radial uniformity coefficients,with an average of 1.09% to 1.17%,while there was no significant influence on the circular uniformity coefficients.
基金This work was supported by the National Natural Science Foundation of China(51679109)the Natural Science Foundation of Jiangsu Province(BK20170555)+2 种基金the Natural Foundation of the Higher Education Institutions of Jiangsu Province(17KJB470001)Special Scientific Research Fund of Agriculture Public Welfare Profession of China(201503130)Jiangsu Scientific Research and Innovation Program for Graduates in the Universities(KYLX15_1062).
文摘One way to adapt to the trend towards low-energy and to improve the hydraulic performance of the impact sprinkler under a low pressure condition is by means of a fixed water dispersion device.A fixed dispersion device disperses jet flow from the nozzle continuously.The shape of the tip,impact angle(θ),diameter(D),and depth in the jet flow(d)have significant influence on the hydraulic performance.In this study,the hydraulic performance characteristics of impact sprinkler as affected by the fixed water dispersion device were studied under indoor conditions.Radial water distributions from the sprinkler were obtained by experiments for the fixed water dispersion devices.MATLAB was used to transform the radial data into net data,and the uniformities were simulated in a square layout from 1 to 2 times the range(R).The droplet size distributions from the fixed water dispersion devices were measured by a laser precipitation monitor(LPM).Results showed that the range increased with the increase of pressure,and the sprinkler with type C_(2) produced a rectangular-shaped water distribution pattern,while the range was maintained.A maximum uniformity of 71.56%,75.56%,77.23%,73.32%,78.88%and 86.67%was found for types A1,B1,C1,A2,B2,and C_(2),respectively under a pressure of 200 kPa.The uniformity from the sprinkler using type C_(2) surpassed 80%,while type C1 fell below.Droplet sizes from type C_(2) was best,and the mean droplet diameter decreased with the increase of pressure.Hence,type C_(2) can be selected for further optimization of the design features to improve the hydraulic performance of the impact sprinkler under low pressure conditions.
