Velocity and pressure result in the filling pattern of plastic melt in injection molding.The temperature field plays an important role and should be simulated correctly and stably because it changes the viscosity significantly

which interacts with velocity and pressure.The GLS(Galerkin/least-squares) method based on the PG( Petrov-Galerkin) method was employed to solve velocity and pressure field stably when equal order interpolation functions were used for velocity and pressure field.The GGLS(Galerkin gradient least-squares) and SUPG(streamline upwind/Petrov-Galerkin) methods were combined to solve temperature equation in a stabilized way in which the SUPG method was used to prevent the oscillation caused by dominated convection

and the GGLS method was used to avoid pseudo-increase of temperature because of small thermal conduction.Numerical examples showed that the temperature results from the GGLS method were more reasonable than the classic Galerkin method.When the filling stage was simulated

the combined GLS/SUPG method gave a valid means for the stabilized and exact solution of temperature field

and at the same time

melt velocity

pressure and flow front could be exactly solved by using the GLS method.