Simulation of flow conditions for natural gas and hydrogen blends in the distribution natural gas network

This study analyzes the improvement of mixture homogeneity between natural gas and hydrogen within a pipeline by inserting a static mixer inside. Recurring to Ansys Fluent, three different cases were simulated to test the mixing. The performance of an helicoidal mixer (KMS) and a KVM mixer were analyzed and compared to the standard T-junction without static mixer. The required distance for achieving a homogeneous mixture, measured by the coefficient of variation (COV), was calculated and compared with the resulting pressure loss. The three cases were analyzed for hydrogen injection percentages until 20 % and for a gas pipeline connecting the transmission line to the distribution line (P = 18 bar). The use of static mixers facilitates a faster homogenization of the mixture. Among these mixers, the KVM mixer performed the best, achieving a homogeneous mixture over a shorter distance while incurring a lower pressure loss.