Modelling of complex clearance flow in screw-type machines

The study is concerned about a mathematical modelling of complex clearance flow in two-dimensional models of a male rotor-housing gap and of an undesirable gap caused by the incorrect contact of rotor teeth in a screw-type machine. Both problems are solved as a non-stationary turbulent compressible Newtonian fluid flow with ideal gas properties. The turbulent flow is assumed to be statistically steady and the mathematical model is described by the non-linear conservative system of the compressible Favre-averaged Navier–Stokes (FANS) equations written in non-dimensional form. Its numerical solution is performed using the cell-centred finite volume formulation of the explicit two-step TVD MacCormack scheme which is proposed by Causon and is defined on a structured quadrilateral grid. The algebraic Baldwin–Lomax turbulence model is implemented into the presented numerical code.