A two2scale second2order moment particle t urbulence model accounting for inter2<br />particle collision is developed based on the concept t hat the particle fluct uation can be divided into<br />large2scale one due to t urbulence and small2scale one due to collision with a unified t reatment .<br />Adopting the multiple scale of single2fluid met hod and two2fluid model

t he particle Reynolds<br />st ress equation for two2scale fluct uation

t he energy t ransfer rate equation for large2scale<br />fluct uation

t he turbulent kinetic energy dissipation rate equation for small2scale fluct uation

and<br />t he gas2particle velocity correlation equation for two2scale fluct uation are all derived and closed.<br />The presented model is employed to simulate gas2particle flows in a sudden2expansion chamber

<br />and the simulated result s coincide well wit h t he experimental ones. It is al so demonst rated t hat<br />t he presented two2scale model is wit h higher calculating accuracy