M. H. Ranginkaman, A. Haghighi, H. M. Vali Samani,
Volume 6, Issue 1 (1-2016)
Abstract
Inverse Transient Analysis (ITA) is a powerful approach for leak detection of pipelines. When the pipe transient flow is analyzed in frequency domain the ITA is called Inverse Frequency Response Analysis (IFRA). To implement an IFRA for leak detection, a transient state is initiated in the pipe by fast closure of the downstream end valve. Then, the pressure time history at the valve location is measured. Using the Fast Fourier Transform (FFT) the measured signal is transferred into the frequency domain. Besides, using the transfer matrix method, a frequency response analysis model for the pipeline is developed as a function of the leak parameters including the number, location and size of leaks. This model predicts the frequency responses of the pipe in return for any random set of leak parameters. Then, a nonlinear inverse problem is defined to minimize the discrepancies between the observed and predicted responses at the valve location. To find the pipeline leaks the method of Particle Swarm Optimization (PSO) is coupled to the transient analysis model while, the leak parameters are the optimization decision variables. The model is successfully applied against an example pipeline and in both terms of efficiency and reliability the results are satisfactory.
A. Ahmadi Najl, A. Haghighi, H. M. Vali Samani,
Volume 6, Issue 2 (6-2016)
Abstract
The interbasin water transfer is a remedy to mitigate the negative issues of water shortage in arid and semi-arid regions. In a water transfer project the receiving basin always benefits while, the sending basin may suffer. In this study, the project of interbasin water transfer from Dez water resources system in south-west of Iran to the central part of the contrary is
investigated during a drought period. To this end, a multi-objective optimization model is developed based on the Non Dominated Sorting Genetic Algorithm (NSGA-II). The optimum trade-off between the water supply benefits into and out of the Dez River basin as well as energy production is derived. Formulating the problem as a multi-objective
optimization provides a better insight into the gains and losses of a water transfer project. Analyzing the case study, revealed that to reach an acceptable level of reliability for meeting the water demands it is no longer possible to generate hydropower energy with high levels of reliability.
