摘要：采用计算流体动力学方法对叶轮式湍流磨内部流场进行单相流动数值模拟;通过分析不同转速、不同出口压力下磨腔内部气体温度、压力、速度、速度梯度、湍动能等流场参数,探讨物料粉碎机理及湍流磨工作特性。结果表明:叶轮与轴向齿槽间隙内切向速度梯度大于15 000 s^-1,且存在峭壁结构,为主要研磨区;湍流磨转速大于6 000 r/min时温升较大,且随转速增大温升越来越剧烈;出口段气流存在强烈旋转,表现为强迫涡流,涡流使气体沿径向形成压力梯度,管道中心出现负压,进而引起回流。

关键词：湍流磨；数值模拟；单相流动；湍流；回流

Abstract：A computational fluid dynamics method was used to perform single phase flow in a impeller-type turbulence mill. The internal flow field features including gas temperature, pressure,velocity, velocity gradient, turbulence kinetic energy, etc was analyzed with different rotating speed and back pressure to gain a preliminary knowledge of the material crushing mechanism and operating characteristic of the mill. The results indicate that circumferential velocity gradient in the gap of the impeller and the stationary casing is bigger than 15 000 s^-1. There exists a cliff structure in the gap which constitute the main grinding zone. The temperature rise is relatively large when the rotating speed is bigger than 6 000 r/min and it becomes more and more violent with the increment of the rotating speed. There exists a strong rotation of gas flow in the exit section which behaves as a forced vortex flow. As a result, pressure gradient develops along radial direction and negative pressure appears in the central part of the outlet pipe which causes back flow.

Keywords: turbulence mill；numerical simulation；single-phase flow；turbulent flow；back flow