| Air vessel is a quite effective device to prevent water hammer in long-distance water-supply pipelines. It is a trial and error process that designers usually depend on empirical formulas and some graphs to choose air vessel parameters in practical engineering. This paper simulates water hammer following pump failure in actual long-distance water-supply pipelines and uses the sequential quadratic programming (SQP) and genetic algorithm (GA) to optimize air vessel parameters.This paper, firstly, makes use of the method of characteristic (MOC) to simulate water hammer following pump failure in actual long-distance water-supply pipelines by none of protective measures and some ones including multi-function control valves, both the air vessel and check valve, both the air vessel and multi-function control valve. Secondly, air vessel parameters optimization model is established, which includes an objective function, decision parameters and constraint conditions. Finally, the SQP and GA methods are used to optimize air vessel parameters in actual long-distance water-supply pipelines.The research work shows that multi-function control valves cannot work very well when both the multi-function control valve and air vessel are used to protect pipelines against water hammer resulting from pump failure, which can be replaced by a check valve. The effect of preventing water hammer is good when both the check valve and air vessel are used to protect pipelines. The initial gas and water volume in vessel are crucial parameters for optimizing air vessel parameters to minimize the sizes and costs. The research work also demonstrates that the vessel volume and the ratio of initial gas and water volumes are vital decision parameters in selecting and debugging air vessel parameters in practical engineering. The SQP method can satisfy the accuracy attained by the GA method for air vessel parameters optimization. Therefore the SQP method can optimize air vessel parameters in actual projects in order to shorten optimization times and improve the optimization efficiency. This research work is the theoretical reference to design and debug air vessel parameters in practical engineering. |
