Ithas been well-known that many industrial applications that use centrifugalcompressors have continuously demanded for more and more efficient machinesin the past decade or so. However, the current markettrend indicates that there is a strong demand among theend users for reduced delivery times of these efficient compressors.This, in turn, requires that the aerodynamic design of highlyefficient centrifugal stages be completed within shorter time frames. Inorder to meet these challenges, it is mandatory to involvemodern computational analysis tools such as Computational Fluid Dynamics (CFD)as a routine design tool for the aerodynamic engineer. Thispresentation discusses a hierological structure for CFD analysis along withan overview of limitations and benefits for each classification withinthis structure. Usage and results pertaining to the implementation ofthis structure at Cameron's Compression System will also be covered.Accordingly, a discussion of aerodynamic design practices (both current andhistorical) will be offered. It should be obvious to thereader that the goal of design integration would require theprimary focus to be towards validation of the commercial CFDcode. Results presented were obtained using the StarCCM + CFDpackage developed by CD-Adapco. As mentioned earlier, CFD analysis canbe described as a hierological structure consisting of 4 levels.At level 1, the analysis component consists of an impellercoupled with a vaneless diffuser region under a steady stateflow condition. On level 2, the model involves an impellerand low solidity diffuser row analysis using a mixing planeinterface. Level 3 facilitates the consideration of entire impeller andan entire diffuser with a full set of diffuser bladeswithin a transient framework. These levels (1 through 3) includethe assumption of a dump collector and imply a circumferentialperiodicity at the exit. Also, models for level 2 andlevel 3 incorporate the use of a 1-d modeling topredict overall stage performance. Level 4, the most sophisticated model,involves a full-stage analysis of an unsteady turbulent flow throughthe entire centrifugal stage, all the way from impeller inletto the discharge of the scroll/volute/collector. At this level, theoverall stage performance is predicted directly from the CFD analyses.The paper compares the results of each level of analyseswith the test data and discusses the potential benefits aswell as limitations of each level of analyses.