Computational fluid dynamics (CFD)-predicting fluid motion with a computer is being used to streamline the task of designing kraft recovery furnaces. Systems designers can now use CFD to simulate gas flow fields in the furnace under isothermal conditions. The results of CFD simulations are typically reported in the form of plotted vectors and contours, which can be difficult to interpret. One solution to the interpretation problem is to exploit the graphics capabilities embodied in most CFD programs with the help of scientific visualization (SV) software. The SV graphics options offer the user the ability to animate images, remove surfaces, and zoom in for close-up views. This article examines the use of SV software and provides several detailed images of simulated flow fields in the lower furnace. In the future, CFD will be used to simulate gas flow patterns along with the complex combustion and heat-transfer processes that occur within the recovery furnace. Equipment suppliers, government agencies, and academic institutions are sponsoring work toward the development of these highly sophisticated computer models.