جستجوی مقالات مرتبط با کلیدواژه « افت های جزئی » در نشریات گروه « آب و خاک »

In this study, a practical procedure was proposed for hydraulic analysis of flow in drip line lateral in the drip irrigation system to determine the major and minor losses of the driplines. In this method, the friction losses between the drippers and local head losses of the drippers were calculated step-by-step and the total pressure losses of the lateral were determined by summation of the head losses. To determine the minor losses of the emitters, the power relationship between the pipe discharge and the measured head losses related to simple and drip line pipes was determined by the nonlinear regression method. Then, the difference of the obtained head losses of these relationships in different discharges was calculated. Then, the power relationship between these results and discharge was determined by using nonlinear regression again. Also, Hazen–Williams equation and Darcy-Weisbach relationship used to determine the friction head losses. The friction coefficient (f) determined using Altshul, Blasius, and Moody diagram. Thus, four different methods of combining minor and friction head losses equations were obtained and evaluated using RE, MAE and RMAE indices. Experiments were conducted on three 60-meter samples of drip lines with emitter spacing of 0.20, 0.40 and 0.50 m and a simple sample with 16 mm diameter at 50, 100, 150, and 200 kPa pressures. The results indicated that the Darcy-Weisbach relationship based on the Blasius relationship was more accurate than the other methods. Also, the performance of the proposed experimental relationships were acceptable to estimate the local head losses. Therefore, the proposed method is recommended to calculate the head losses in the dripline laterals.