Abstract: The flux modification of Harten's second-order TVDscheme, coupled with implicit iteration-analysis algorithm, is employed toovercome the computational stiffness of k-ε turbulence model.Internal flow field of an axisymmetric nozzle and internal-external flowfield of a two-dimensional nozzle are simulated to confirm the improvementof calculation efficiency by the above methods when using improved multigridstrategy. The calculation results are compared with experimental data.