Multiphase flow dynamics analysis in jet cavitation nozzles: a novel approach for optimizing oily sludge treatment efficiency

The mixed multiphase flow model, RNG (Re-normalization group) k-ε turbulence model and Schnerr and Sauer cavitation dynamics model were used to numerically simulate the flow field of a jet cavitation nozzle, and the influence of the nozzle structure on the cavitation intensity was studied. The actual effect of three types of throat diameter nozzles in the treatment of oily sludge was explored. The simulation results show that the cavitation effect is best when the nozzle throat diameter is 0.4 mm, the diffusion angle is 50°, the contraction length is 8 mm, and the diffusion length is 6 mm. The experimental results show that in the case of a nozzle with a throat diameter of 0.4 mm, the oil content of the oily sludge after cavitation is reduced from 24.9 % to 9.8 %, and the total petroleum hydrocarbon (TPH) content is reduced by 84.8 %.