Temperature field evolution and optimization simulation of cryo-adsorptive hydrogen vessel filling over a wide pressure range

Cryo-adsorptive hydrogen storage is a promising densified hydrogen storage approach, but thermal effects such as adsorption heat during filling can cause non-uniform temperature fields and reduce storage performance. In this work, a cryo-adsorptive hydrogen storage vessel packed with MIL-101(Cr) is modeled, and the temperature-field evolution during filling up to 50 MPa is simulated. The effects of mass flow rate, filling temperature, initial pressure, and initial temperature on temperature rise and hydrogen storage density are analyzed. At an initial temperature of 80 K and a filling rate of 5 g/s, the maximum temperature reaches 100.20 K at 50 MPa, with a heat-accumulation region near the vessel top. With 12 axial conductive fins under wall cooling conditions, the maximum temperature is reduced to 93.44 K, and the cooling time is significantly shortened. Considering thermal enhancement and storage-density loss, 12-16 axial fins are recommended, corresponding to fin-enhancement effectiveness factors of 9.96-12.97%.