Model construction and verification of nozzle range calculation

Abstract

Abstract To determine Calculation method of sprinklerand micro-sprinklers, computational models for sprinkler range model is constructed, based on hydraulic parameters of nozzle diameter, working pressure, Installation Heights, spray elevation angle, discharge coefficient, wind direction and speed, water flow regime, and water droplet motion in air, etc., as well by Newton's second law of motion, aerodynamics, and fluid mechanics principles, and by experimental verification for common sprinkler range, nozzle diameter, working pressure, spray elevation angle, Installation Heights, discharge coefficient, and wind direction and speed. The results indicate that sprinkler range with nozzle diameter, working pressure, Installation Heights, spray elevation angle, discharge coefficient, wind direction and speed, water flow regime, and droplet motion in air was in highly significant correlation, the sprinkler range Progressive decreases around the sprinkler along the sprinkler range direction, as well increases by 5.2342%~10.6278% in the downwind direction and decreases by 4.6897%~9.8623% in the headwind direction compared with no wind. The wind speed increases, then the range decreases, and the wind direction shifts, then the range shifts, so the wind direction wind speed changes then the range changes. The coefficients of determination, the consistency Index, the root mean square error, absolute error, relative error between calculated Values and Measured Values of computational models are 0.9146, 0.9205, 8.7748%, 10.4980%, 8.2524% and 8.1421%, respectively. The smaller coefficients of determination and the consistency Index of calculated Values and Measured Values of computational model under windy conditions comparing with no wind, as well the larger root error, deviation, absolute error and relative error. The calculation model in this paper has a clear principle, comprehensive influence factors, complete physical meaning, high calculation accuracy, small error, and wide applicability. This calculation model can effectively reflect the nozzle range change law. This study provides theoretical basis for determining the sprinkler hydraulic performance and provides technology support for Planning and Design of sprinkler irrigation system.