Detailed numerical simulations are performed for oxygen transfer around and within a circular scaffold for animal cell culture. The oxygen concentration distribution, minimum oxygen concentration within the scaffold and its corresponding location, as well as the Sherwood number are presented at different Darcy numbers, Reynolds numbers and Damkohler numbers. It is found that if the Reynolds number is increased from 1 to 30, the Sherwood number increases 1 time for a Darcy number of 5 x 10(-6) while 34 times for a Darcy number of 5 x 10(-4). The location of the minimum oxygen concentration is close to the centre of the scaffold when the Darcy number is smaller than about 5 x 10(-5) or the Reynolds number is smaller than about 1, especially for the Damkohler number larger than O(10). The present study may provide useful guidance on design of the bioreactor with scaffold as well as choosing optimal operating parameters. (C) 2012 Elsevier Ltd. All rights reserved.