Numerical predictions of the drag coefficients of irregular particles in an HTGR

Highlights: • The drag coefficient increases with Re_p decreasing and increase of flow angle. • Drag coefficient is affected by flow angle more obvious at low Re_p. • The friction drag plays a dominant role while pressure drag affected by flow angle. • Drag coefficient correlation agrees well with the RANS results in HTGR conditions. - Abstract: The present study analyzed the drag coefficient of simplified graphite dust particles in an HTGR using a computational fluid dynamics (CFD) model. The effects of the particle Reynolds number, flow angle and the percentage contribution of the drag coefficient are discussed. The results show that the drag coefficient for irregular particles decreases with increasing particles Reynolds number but increasing with increasing flow angle. The friction on the micron particles is the main component of the total force, while the effect of the flow angle on the drag coefficient contributes to the pressure drag. The results are correlated into accurate correlations based on the specific particles analyzed here.