Modeling pressure swirl nozzle - need help!
 

Hi! I am trying to model flow inside a pressure swirl atomizer using mixtue model and encountered some problems i cant handle. Fluent ver. 6.3.26, 3d mesh with approx. 500 000 tetrahedral cells (i use rotational periodic bc so the mesh covers 1/4 of the nozzle and interval size for the mesh is 0.2 mm), PBNS, RNGKE, inlet BC is pressure inet 1000-100000 pascal, outlet BC is also pressure outlet 0 pascal. Problem is considered as time dependent with fixed time step 0.0001 sec. For pressure-velocity coupling i use PISO, pressure discret. is PRESTO!. After coulple of iteration at first time step solution stops with error "invalid number". I tried changing different valies for inlet pressure, turbulence intensity and scale at BC, altering between vel inlet and pressure inlet, laminar and rngke and standart ke, no results at all!

Please need advice on what should be the problem setup! May be problem is tetrahedral mesh, i tried to make it hex but couldnt.