关键词: 湍动射流, 计算流体力学, 多相流, DTB结晶器, 结晶

Abstract:

The circulation jet flow field in a DTB evaporating crystallizer was simulated and analyzed using RNG k-ε turbulent model. Based on the Eulerian multiphase flow model, the structure of the crystallizer and the flow field in the crystallizer were simulated and optimized. The simulation results showed that the jet could satisfy linear expansion in the draft tube and the axial velocity distribution basically met the Gaussian distribution. For the jet flow at entrance region of the draft tube, the reciprocal of axis velocity and flow distance showed a good linearity. However, axial velocity decayed faster with the development of the jet flow. The area ratio (β) of the annulus between draft tube and the baffle to the cross-section of the draft tube significantly influenced the circulation flow ratio (γ). With the increase of β, γ increased at first, and then decreased, accordingly an optimal γ exists. Although the particle concentration of the crystal slurry decreased along the radial direction in the draft tube, it still had a more even distribution within the optimized structure crystallizer.

Key words: turbulent jet, CFD, multiphase flow, DTB crystallizer, crystallization