Multi-objective optimization and performance assessment of hydrogen-blending static mixers incorporating vortex generators

Efficient mixing of hydrogen-blended natural gas is critical for safe and large-scale hydrogen transportation. This study proposes a vortex generator-based static mixer to enhance hydrogen dispersion by strengthening the hydrogen jet and inducing counter-rotating vortices. Five structural parameters, including angle of attack, height, trailing-edge chord length, number of vortex generators, and hydrogen inlet diameter, were optimized using orthogonal experimental design, entropy weight method, and Technique for Order Preference by Similarity to Ideal Solution. The optimal configuration was obtained at an angle of attack of 90°, height of 300 mm, trailing-edge chord length of 200 mm, three vortex generators, and hydrogen inlet diameter of 120 mm. Compared with a conventional Kenics static mixer, the proposed mixer reduced the mixing lengths required for 90% and 95% hydrogen concentration uniformity by 3.5 m and 4.3 m, respectively, while decreasing pressure drop by 3556 Pa. These results demonstrate its superior mixing efficiency and lower flow resistance.