A promising method to describe the fluid dynamics of highly loaded particle flows is the Eulerian representation. In this approach, the solid phase is treated as a continuum, although physically it consists of individual particles. This is possible by using physical models derived from the kinetic theory of granular flow. Central to these models is the so-called granular temperature, representing the specific fluctuating kinetic energy of the particles. In this paper, several forms proposed for these models are summarized and different descriptions of granular temperature are investigated. Furthermore, an alternative approach derived from soil mechanics is tested. Measurements of a two-dimensional bubbling bed found in literature are finally used to verify the results.