A quickly discrete-continuous phase interaction model for pore-scale motion of droplets in porous foams

Abstract

The expensive computational cost of pore-scale modeling of droplets in porous foams limits the understanding and application of spray cooling techniques. Thus, a numerical model that can cheaply and quickly predict the interaction of moving droplets with the foam skeleton is valuable. In this work, a novel model based on foam geometry and octree (FGAO) is proposed for the rapid evaluation of discrete-continuous phase interactions in porous foams. The performance of the FGAO model is investigated for different Stokes and Weber numbers, with the full pore-scale model as a benchmark. The results show that the accuracy improves as the Stokes number increases, but the effect of the Weber number on the accuracy is complicated. The accuracy decreases as the We close to the intersection of the interaction region, while it improves as the Weber number is far away from the intersection of the interaction region. To quantitatively assess the error, a relative error (RE) and a weighted mean absolute percentage error (WMAPE) are introduced. The results show that the FGAO model has excellent accuracy with RE < 2.79 % at Stk > 10. At the criteria of WMAPE, the FGAO model performs well at the condition of the initial Weber number is far away from the intersection of the region of the Bai-Gosman model, with WMAPE < 7.3 % at We = 1 Stk = 50 and WMAPE < 3.9 % at We = 400 Stk = 50. Finally, the current method offers a significant advantage in computational speed compared to the full pore-scale model, with an improvement of about 62.9 times for Stk = 50, We = 10.