Abstract: In order to solve the problem of poor separation efficiency of traditional plate-type coalescer structures, a novel type of coalescer with outlet baffles was proposed, and a computational fluid dynamics (CFD) method was used. The effects of the bonding plate length (l), the inclined angle (θ), the baffle height (h) and the baffle angle (α) on the separation performance of the novel coalescer were investigated by mixture model of Fluent code and standard k-? model, and the optimal structural parameters were determined. The results showed that the coalescer had a significant effect on the separation effect of the oil-water separator; under the same conditions, the separation efficiency of the coalescer with outlet baffles was 1.2% higher than that without outlet baffles. For the four structural parameters, the separation efficiency of the separator with outlet baffles showed a trend of first increasing and then decreasing with the increase of a single structural parameter, and the optimal value was l/L=3/12 (L is the length of separator), θ=30°, h/H=7/10 (H is the spacing of baffle) and α=75°; the optimal combination of four kinds of structural parameters obtained by response surface analysis was l=421.67 mm, θ=45.07°, h=8.84 mm and α=112.70°. The separation efficiency of the separator with outlet baffles was 97.67%.

Key words: oil-water separator, coalescer, outlet baffles, response surface analysis, collection efficiency