3D numerical simulation and optimization of honeycomb regenerators with parallel or crosswise arrangement of circular holes

In the present work, with User-Defined Functions compiled to express the alternate and opposite flow of air and flue gas, 3D numerical model based on ANSYS Fluent is constructed for ceramic honeycomb regenerators. The fundamental of the complex heat transfer in honeycomb regenerators is analyzed with temperature contours and curves. The effects of regenerator length (L) and switch time (tau) on thermal and hydraulic behaviors are investigated for the regenerators with parallel and crosswise arrangements of circular holes, respectively. For the validation, the tested honeycomb regenerator released in the literature is computed with current 3D modeling method. The current research demonstrates that the air preheating temperature (T-ao) and regenerator effectiveness (epsilon) rise with the increment of L or the decrement of tau. The flow resistance has a weak relation to tau but rises notably with the increasing L. The regenerator with crosswise holes could generate the same epsilon as that of parallel holes at a small tau, while the latter has a smaller reduction of epsilon (or T-ao) over a large increment of tau. As for the present work, the regenerators with parallel and crosswise holes take the optimal lengths of similar to 307 mm (tau = 90 s) and 342 mm (tau = 30 s), respectively.