Transient Analysis of an Experimental Mercury Flow Loop for SNS Validation Available to Purchase

A transient fluid acoustic model is compared with experimental data obtained from induced pump trips in a mercury loop. The facility consists of a stainless steel loop filled with 19,000 kg (21 tons) of mercury that is motivated by a 41 KW (55 hp) centrifugal pump through 37 m of piping in a full transit. At nominal operation, the volumetric flow rate from the pump discharge is 1400 LPM and velocities throughout the loop range from 0.3 to 3 m/s. A computer model of the mercury loop was made using the fluid transient code from Applied Flow Technology Impulse™. Loss of power to the mercury centrifugal pump may lead to fluidhammer, in which a cavity formed in low pressure regions created downstream of the pump outlet after the pump power is lost, collapses and gives rise to a pressure pulse. Fluidhammer has been created experimentally through a series of induced trips of the mercury centrifugal pump. Pump speed, volumetric flow rates, and dynamic pressures were gathered during the transient events. This data has provided information about the initialization, magnitude, and propagation of the pressure pulses associated with fluidhammer. The data gathered from these tests is presented and compared to simulation results gained from the computer model. Pressure magnitudes found in trip simulations at normal operating conditions nearly match those found in experiments, and other trends of the time traces show reasonable agreement.