NASA codes. To size centrifugal compressors and radial inflow turbines, the
codes CCD and RTD are used. These are design codes, which output the key
dimensions required to meet the input design point performance. For
off-design analysis including performance map generation, the companion
codes CCOD and RTOD are used. For axial compressors, the meanline codes
are more advanced expanding the analysis from hub to shroud. These
spanwise codes include CSPAN, ACD, and ACOD. For axial turbines, the
primary design codes are TURBAN and TD2.
Although development work is still continuing on some of these programs,
most of the codes were written in the 1970s and 80s and were validated
extensively with test data.