Electrochemistry, as its name eludes, unites theories for chemical reactions and electric currents. Reactions that occur at electrode surfaces often involve ions and electrons that generate currents in the fluid and solid domains, respectively. These currents can be modeled in STAR-CCM+ to varying degrees of complexity; such as primary, secondary, and tertiary current distributions.
Primary current distributions neglect electrode kinetics completely and only account for ohmic losses due to fluid resistance. Secondary current distributions account for ohmic losses in the fluid as well as charge-transfer resistance due to reactions at the electrode surfaces. The assumptions associated with a secondary current distribution are generally considered only to be valid when the fluid is well mixed. When species transport to the electrode surface becomes important, tertiary current distributions are required, which incorporate the concentration dependence of electrode reactions.
Increasingly engineers want to simulate complex electrochemically driven processes such as corrosion, fuel cell behavior, flow battery performance and many more diverse mechanisms. With this in mind CD-adapco has created a general purpose electrochemistry approach which allows the user model such processes and harness the power of STR-CCM+’s geometry and meshing capabilities. Previously such complex electrochemistry problems were solved using academic codes constrained to two dimensions or requiring major geometry simplification. This new development in STAR-CCM+ opens the door to detailed, real world electrochemistry simulations. Electrochemistry simulation in STAR-CCM+ can be used to model applications such as: