Static Application of Transient Hydrodynamic Loads on Vessel Internal Structures As a Result of Pulse Jet Mixer Overblow: Low-Frequency Loads

Abstract

At the Hanford Waste Treatment and Immobilization Plant (WTP), various vessels are designed to be agitated with internal pulse jet mixers (PJMs) in order to provide a means of mixing with no moving parts local to the vessel. PJMs are operated by use of an applied vacuum to draw liquid in followed by motive air to force liquid out (while not completely discharging all the liquid). This continual operation results in mixing of the vessel contents. In off-normal conditions, PJMs may completely discharge resulting in air rapidly injected into the vessel (PJM overblow). An evaluation is complete to determine the statically applied transient Rayleigh-Plesset bubble loads resulting from PJM overblow on the vessel’s internal submerged structures. The low-frequency bubble loads on internal structures is determined via analysis of overblow test data, application of the Rayleigh-Plesset equation based on bubble pressure, PJM nozzle critical flow ratios, conservation of momentum, the relative equation of motion of a submerged non-fixed structure subject to both relative drag and relative acceleration, non-flow boundary conditions, use of a displacement-response spectra, and Hooke’s Law. This theoretical Rayleigh-Plesset bubble loads model accounts for various vessel and internal submerged structure designs and different operational states: PJM cavity pressure, liquid density, depth of submerged bubble, and both choked or non-choked flow through the PJM nozzle.