جستجوی مقالات مرتبط با کلیدواژه "pipes roughness" در نشریات گروه "مهندسی آب"

Uncertainty in the planned water demand and changes in the roughness values ​​of the pipes are among the common cases of unfavorable performance of water distribution networks. In this research, a model has been developed to optimize networks that have been implemented but need to be strengthened under conditions of uncertainty. In this model, the EPANET simulator model was combined with optimization genetic algorithm in MATLAB programming environment. In such a way that it is first created using the concept of fuzzy logic, fuzzy membership functions of the input parameters(nodal demand and pipe roughness coefficient), then by considering the relationship between demands and pressure head requirements at nodes and using (Gupta and Bhave 2007) impact method The fuzzy optimization model is converted to a deterministic model and finally, the diameter of the pipes that should be installed parallel to the existing pipes is obtained by using the genetic algorithm. The method created for a typical network from past researches is checked by changing the uncertainty level, the results indicated a 28% increase in the cost of the network with a 50% increase in considered uncertainties and a 7.5% decrease in cost by applying a tolerance of 0.75 meters in the desirable pressure head. The proposed method based on the genetic algorithm is completely suitable and creates a solution that provides the required pressures in the worst situation variables.

The friction factor of pipes in water distribution networks is different from the laboratory values due to the connections, installation method and created bights. Passing of time, erosion and sedimentation in pipes are also factors affecting roughness. Therefore, the roughness of pipes should be calibrated during network modeling. In this research, a new optimization method, called sensitivity analysis method was introduced for roughness calibration. In this method, first the pipes are grouped based on the material and diameter of pipes. Then, using sensitivity analysis it is determined what the effect of changing the roughness of different groups on node pressures is. In the following, roughness calibration is performed according to the importance of the groups respectively. This method was investigated on a real network with assumed changes. In order to compare the efficiency of the present method, the results obtained were compared with the results obtained from the calibration tool of WaterGEMS software. Fitness that is obtained by present study method and output of WaterGEMS in studied network are 0.02 and 8.11 centimeters, respectively. Obtained results show the high ability of this method in pipes network roughness calibration.