Multiscale Modeling For Transport And Adsorption In Porous Structures Of Carbon-Based Materials For Hydrogen Storage

Adsorptive hydrogen storage of carbon-based materials because of its safe and efficient becomes a hot research of hydrogen storage, the transport and adsorption in porous structures of carbon-based materials is the focus of adsorptive hydrogen storage research. This paper considers the hydrogen storage tank system as the study object, has designed the multi-scale simulation software integration platform, has built the association of the system and macro-scale adsorptive hydrogen storage models, has simulated the four processes of charging, dormancy, discharging and dormancy using the two scale models for researching the transport and adsorption of activated carbon porous media.Secondly, this paper has realized software integration of Simulink, Fluent, Comsol and Origin, has built a multi-scale simulation software integration platform for the simulating work of the pre-processing, solving and post-processing in the Comsol with Matlab environment. The interfaces are developed between the multi-scale simulation software integration platform and Simulink, Fluent, Comsol and Origin software for calling and data exchanging by analyzing structures and characteristics of the Matlab GUIDE-generated M-file, Fluent journal file, Comsol M file and Calling Origin objects to achieve effective integration of four software.Thirdly, the client program in Fluent UDF and server program in Simulink C file version's S-function are written to achieve data exchanging by Winsock network socket communication mechanism for the Fluent/Simulink co-simulation; the Comsol solving is embedded in the Simulink M file version's S-function to achieve data exchanging for the Fluent/Simulink co-simulation. The association and its implementation process of adsorptive hydrogen storage simulating in hydrogen storage tank are given between Simulink and Fluent, Simulink and Comsol.Then, the four processes of charging, dormancy, discharging and dormancy of the hydrogen tank with activated carbon are simulated in the multi-scale simulation software integration platform by calling the Simulink, Comsol and Fluent software for solving tank temperature, pressure, absolute adsorption density and adsorption quality. The three kinds of simulation results are compared with experimental results for validation. The results of comparison show that Simulink, Fluent, Comsol simulation are in agreement with experimental results, so the system and macro models established in this paper can describe the process of adsorptive hydrogen storage in the hydrogen storage tank. The simulation results of the system and macro model show the mass balance of hydrogen, the quality of adsorption phase hydrogen in 39% micro porosity is greater than that of gas phase hydrogen in 49% activated carbon bed porosity (the difference is about 2.5g), that shows the potential advantages of adsorptive hydrogen storage.Finally, the parameters such as the tank size, mass flow rate of charging and discharging and effective thermal conductivity are researched in the four processes. The Simulating results show that:in the same volume of the tank, increasing the surface area of hydrogen storage tank and the effective thermal conductivity can reduce the hydrogen storage tank temperature and conduce to improve the adsorption capacity of hydrogen storage tank; within the permissible pressure and temperature range of the hydrogen storage tank, in the same the quality of the charging process, the higher mass flow rate of charging will bring the greater peak pressure and temperature hydrogen storage tank, however it increases the adsorption rate of hydrogen storage tank; the mass flow rate of discharging is more higher, the desorption rate is more greater.