Alternative Design Strategy for Water-Hammer Control in Pressurized-Pipe Flow

This paper proposed a design technique to dampen water-hammer surges into an existing steel piping system based on replacing a short-section of the transient sensitive region of the main piping system by another one made of polymeric material. The flow behavior was described using a one dimensional unconventional water hammer model based on the Ramos formulation to account for pipe-wall deformation and unsteady friction losses. The numerical solver was performed using the fixed gird Method of Characteristics. The effectiveness of the proposed design technique was assessed with regard to water-hammer up-surge scenario, using a high- or low-density polyethylene (HDPE or LDPE) for the replaced short-section. Results demonstrated that the utilized technique provided a useful tool to soften severe water-hammer surges. Additionally, the pressure surge softening was slightly more important for the case of a short-section made of LDPE polymeric material than that using an HDPE polymeric material. However, it was observed that the proposed technique induced an amplification of the radial-strain magnitude and spread-out of the period of wave oscillations. It was also found that the amortization of pressure amplitude, and reciprocally the radial strain magnitude, was strongly dependent upon the short-section size and material.