Analysis of Structural Parameters’ Influence on Separation Performance in a Gas–Liquid Cyclone Separator

Hydraulic systems are widely used in industry, and gas contamination of hydraulic oil reduces reliability. This study quantifies how the primary geometry of a gas–liquid cyclone separator affects separation performance and proposes an optimal parameter matching scheme. An orthogonal design, combined with numerical simulations and visualization experiments, evaluated five factors: chamber diameter D, chamber height H, overflow pipe diameter Don, insertion depth of the overflow pipe Hon, and underflow orifice diameter Ddown. Considering mixture entrainment, three metrics were used: direct separation efficiency α, split ratio β, and the actual separation efficiency γ, defined as the product of α and β. Range analysis and variance analysis show that β is governed by outlet sizing, with Don contributing 56.87% and Ddown contributing 39.26%. γ is dominated by body scale parameters, with D contributing 58.79%, Hon contributing 21.18%, and H contributing 13.27%. The optimized geometry achieves γ of about 80.8%. Experiments confirm consistent trends from 0.5% to 8% gas volume fraction, with separation generally above 77% and simulation-to-experiment differences below 20% when the gas fraction exceeds 1%.