Transient flow simulation, analysis and protection of pipeline systems

This paper investigated the problems and impacts of transient flow in pipeline systems due to pump power failure. The impact of different protection devices was presented to assure surge protection for the pipeline system. A model via Bentley HAMMER V8.0 Edition was employed to analyse and simulate hydraulic transients in the pipeline system, and protection alternatives were studied. Surge protection included using only an air vessel, using an air vessel and two surge tanks, and employing five air vessels and vacuum breaker. The obtained results for pressures, heads, and cavitation along the pipeline system were graphically presented for various operating conditions. Using five air vessels with vacuum breaker valve as surge protection proved to be more effective and economical against pump power failure. Changing the flow density did not have a significant impact on the pressures. For protection with an air vessel; it was concluded that the value 40% of the original diameter for inlet pipe diameter of air vessel, and the value of 2/3 of original pipe diameter were critical values for the transient pressures. Cast iron pipes proved to be the best pipe material for all studied volumes of the air vessel. For protection with an air vessel and two surge tanks; as the inlet pipe diameters increased the maximum pressures increased and the minimum pressures decreased. Regression analyses were performed obtaining equations to predict the pressures according to the inlet pipe diameter, the area of surge tank, and the pipe diameter.