Study on optimal water hammer protection for high-head and multi-undulation water conveyance system and empirical formulae for pressure head at nodes

Abstract

ABSTRACT The high-head and multi-undulation water conveyance system, which has a complex pipeline structure, can be prone to water hammer accidents. To prevent damage caused by pipe explosions and dents, measures must be taken to reduce both overpressure and negative pressure during water hammer incidents. This study simulated hydraulic transients using the characteristic curve method and also considered the possible water column separation effect. Parameter optimization and joint scheme selection were conducted for protective measures on the compound air valve group, one-way surge tank, and two-way surge tank. The research identified that the combined protective effect of the slow-closed check valve, compound air valve group, and one-way surge tank is optimal, with low cost and simple operation management. This can be considered the optimal scheme for water hammer protection in the high-head and multi-undulation water conveyance system. The study of the main control points of the pipeline revealed a slight correlation between the maximum relative head differences among nodes. Two empirical formulas, verified under 12 operating conditions, can connect the 9 main nodes with an average relative error mostly ranging from 1 to 5%. The reference significance of the empirical formula for this type of engineering can be verified.