Abstract In this study, computational fluid dynamics (CFD) numerical simulations were applied to comparatively evaluate the flow field of a three-stage cone water-only cyclone (TWOC) with that of a single-stage cone water-only cyclone (SWOC). The reliability of numerical simulations was validated using particle image velocimetry (PIV) technology. According to the analyses of the influences of the flow field characteristics on the separation process, the reasons for the improved separation performance of the TWOC were reasonably explained. The differences in the flow fields inside of the two cyclones only exist in their cone components. In the TWOC cone, the tangential velocity and the axial velocity are both smaller than those of the SWOC, the near-wall fluid is disturbed and two secondary eddies are formed. The secondary eddies increase the looseness of the coal particles and prompt the radial separation of the coal particles. In the TWOC, low-ash coal particles below the theoretical separation density ( δ 50 ) are sufficiently separated into the overflow products throughout the downward motion. Most of the coal particles reaching the cone bottom are high-ash coal particles above δ 50 that are basically discharged through the underflow pipe. Even if some coal particles are forced into the internal spiral flow, these particles will be re-separated by the secondary eddy.

中文翻译：

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三级锥形纯水旋流器流场及分离性能改进研究

摘要 在本研究中，应用计算流体动力学（CFD）数值模拟对三级锥形纯水旋流器（TWOC）与单级锥形纯水旋流器（SWOC）的流场进行比较评估。使用粒子图像测速 (PIV) 技术验证了数值模拟的可靠性。根据流场特性对分离过程的影响分析，合理解释了TWOC分离性能提高的原因。两个旋流器内部流场的差异仅存在于它们的锥体分量上。在 TWOC 锥体中，切向速度和轴向速度均小于 SWOC 的切向速度和轴向速度，近壁流体受到扰动，形成两个次级涡流。二次涡流增加了煤粒的松散度，促使煤粒径向分离。在 TWOC 中，低于理论分离密度 (δ 50 ) 的低灰分煤颗粒在整个向下运动过程中被充分分离成溢流产物。到达锥底的煤粒大部分为δ 50 以上的高灰煤粒，基本通过底流管排出。即使一些煤颗粒被迫进入内部螺旋流，这些颗粒也会被二次涡流重新分离。到达锥底的煤粒大部分为δ 50 以上的高灰煤粒，基本通过底流管排出。即使一些煤颗粒被迫进入内部螺旋流，这些颗粒也会被二次涡流重新分离。到达锥底的煤粒大部分为δ 50 以上的高灰煤粒，基本通过底流管排出。即使一些煤颗粒被迫进入内部螺旋流，这些颗粒也会被二次涡流重新分离。