Study of the deposition of graphite dust in the inlet passageway of intermediate heat exchanger in VHTR

The impact of graphite dust on structural equipment is a potential safety hazard in HTGR. The present study focuses on the graphite particle deposition process on the deflector in the inlet passageway of intermediate heat exchanger and analyzes the effect of particle size on inertial deposition and diffusion deposition. Meanwhile, the particle rebound behavior is considered when the particle impacts the wall. To determine the relevant parameters of the rebound model, the experiments about adhesion are carried out and validated. Then the flow field is simulated in the inlet passageway of intermediate heat exchanger based on k–ε turbulent model, and particle trajectories are predicted by a discrete particle model with rebound boundary. The results show that adhesion force by measures is obviously smaller than theoretical model. In addition, the particle deposition rate decreases first and then increases, and the rebound model makes deposition results more actual.