【摘要】 通过管流法试验得出质量浓度为65.3%的兖州煤水煤浆为剪切增稠的幂流体。将试验得出的流变模型和参数作为计算的依据,运用FLUENT软件提供的非牛顿流体模块,对水煤浆在直管中的流动进行了数值模拟。计算得出水煤浆在管道中流动产生滑移的临界速度,并得到临界速度与管径的变化关系。提出滑移速度新的定义方法,计算得出三个管径中不同平均流速下的滑移速度均为0.02 m/s,表明水煤浆的滑移速度与平均流速和管径呈弱相关。通过对滑移速度进行修正,得出滑移修正后的单位长度压差与实测值相吻合,表明计算模型是正确的。计算得到管道截面水煤浆的表观粘度变化曲线,从管壁到管道中心先缓慢减少再急剧降低。更多还原

【Abstract】 By the experimental method of pipe flow on rheological features,the mass concentration of coal-water slurry of 65.3% is non-Newtonian shear thickening power fluid.Based on the tested model of rheology,the coal-water-slurry was simulated numerically on its straight pipe flows by use of the FLUNT program with some modifications.The predicted pressure drop per unit length was compared with the experiments as a result that a critical velocity at which the wall slip begins was obtained and that the relationship between the critical velocity and the pipe diameter was correlated.A new definition of the slip velocity was proposed and its values were calculated being always 0.02 m/s for different flow rates and different diameters,which verifies that the slip velocity is independent to its pipe mean velocity and the pipe diameter.Subsequently,a modified slip velocity was introduced into the simulation process and an agreement result between the theoretical pressure drop and experimental one was overlapped.The simulation results also show that the superficial viscosity of coal water slurry increases sharply with increase of radius from the pipe center and gradually to the region of the wall area.更多还原