Objective Hydrogen-blended transportation in natural gas pipelines is one of the main methods to realize the large-scale application of hydrogen energy, and a static hydrogen-blended mixer is the key equipment to evenly mix hydrogen and natural gas. It is of great significance to analyze the mixing performance of a static hydrogen-blended mixer by numerical calculation method for the improvement and optimization of the mixer.

Method Based on the evaluation indexes of mixing uniformity and pressure drop level, the mixing performances of different-structure hydrogen-blended mixers were analyzed.

Result The mixing uniformity of hydrogen-blended natural gas could be improved effectively by blocking the outlet of the hydrogen injection pipe and making injection holes around it. Compared with other structures, the mixing performance of the SK mixer is better, its pressure drop is 69.88 kPa, and the comprehensive mixing coefficient is 1.328. The length and twist angle of the hydrogen-blended mixer had a significant influence on the mixing performance, while the thickness had a relatively little influence on the mixing performance. The series mixer had a great influence on the mixing effect.

Conclusion In a mixed transportation pipeline, the mixing performance of the SK mixer is the best when the length of the turbulence element is 750 mm, the thickness is 7 mm, the twist angle is 180° and the number of series is 3.