立式水力碎浆机内部浆料流场数值模拟及其新型槽体结构的研究(一)

Numerical Simulation of Fiber Slurry Flow Field inside the Vertical Hydraulic Pulper and Research on New Type of Its Tank Structure(Ι)

中文关键词:  O形立式水力碎浆机  D形立式水力碎浆机  FLUENT软件  数值模拟  浆料流场分布

Key Words:O-shaped vertical hydraulic pulper  D-shaped vertical hydraulic pulper  Fluent  numerical simulation  distribution of fiber slurry flow

中文摘要:

      以高效、节能、运行平衡安全为主要依据,在分析国内外现有专利和应用中的立式水力碎浆机槽体结构型式基础上,运用FLUENT软件对O形和D形2类槽体结构中浆浓5%的浆料流场数值模拟,得到两者内部流场的压力、流速和湍流强度的分布并进行对比分析。结果表明,传统O形和D形槽体结构内部流场均为垂直环流和水平旋流合成的漩涡流；传统O形内部流场对称、运行平衡稳定,但其高湍流强度区域局限于下部转子旋转区域附近,上部和下部流场湍流强度相差1159%,且顶部边缘处浆料圆周切向速度为0而缺乏碎解动力；D形槽体中心低湍流区域半径缩小到O形的13.0%,湍流强度明显增强,但浆料径向撞击槽壁致使比O形多造成227%的动能浪费,且内部流场不对称使设备运行缺乏平衡稳定性。

Abstract:

      According to the assessment principles for pulpers including high efficiency, low energy consumption and running balance, based on the analysis of the structures of patented and applied vertical hydraulic pulpers domestically and abroad, using Fluent software to simulate the flow field of flow slurry at 5% consistency inside the O-shaped and D-shaped tanks, the distribution of pressure, velocity and turbulence intensity of both flow fields were obtained and analyzed. The results showed that the flow fields inside the O-shaped and D-shaped were vortex-like including a facade circulation and a horizontal swirling；the flow field inside the O-shaped was symmetrical and balanced, but the high-turbulence intensity area was limited to the rotor spinning region, and the turbulence intensity of the upper part was 1159% lower than that of the bottom part, the tangential velocity at the edge of the top of the flow field was zero and it was short of impact power；the flow field inside the D-shaped was with obviously increased turbulence intensity, and at the center of the D-shaped tank, the radius of low-turbulence intensity area was only 13.0% of the O-shaped tank； however, energy consumption inside the D-shaped tank was 22.7% higher caused by radially hitting the wall, and the D-shaped tank was with unbalanced running because of its unsymmetrical flow field.