Investigation on the effects of hydrogen and natural gas blending flow characteristics in various static mixers

Hydrogen blending of natural gas is an effective way to achieve carbon neutrality. In order to evaluate the influence of different static mixers on the mixing performance of natural gas and hydrogen, numerical simulation methods were used to analyze in detail the effects of SMX-type static mixers, LPD-type static mixers, and KSM-type static mixers on the mixing uniformity, internal flow field structure, and pressure loss of natural gas and hydrogen. The results show that in terms of blending uniformity, SMX static mixer > LPD static mixer > KSM static mixer. Based on flow characteristics, the spiral plate of the KSM static mixer reduces the time and opportunity for air flow to contact each other, the two elliptical plates of the LPD static mixer promote the mixing of the mixed gas to generate eddy current, and the SMX static mixer can realize the mixing in two dimensions: flow direction and radial direction. For pressure loss, the pressure loss of the three static mixers increased with the increase in the number of mixing units and basically showed a linear increase, and the pressure loss of the LPD static mixer was about twice that of the SMX static mixer and the KSM static mixer.