Abstract: Reynolds-averaged compressible Navier-Stokes equations are solved numerically for pneumatic spool valves at the conditions of different openings, different interface tube diameter with Spalart-Allmaras (S-A) turbulent model, finite-volume schemes and sufficiently fine unstructured grids. The results demonstrate favorable agreement with experimental data. Flow field indicates conductive value C and the critical pressure ratio b are improved by changing openings. The influence of different interface tube diameter to flowrate characteristics is given. At last, how to design the spool valves are put forward. It has practical significance for us to design lower energy loss pneumatic spool valves.

Key words: Flow path, Flow field calculation, Flowrate characteristics, Pneumatic spool valves, S-A model