水力空化对褐煤水煤浆流变特性影响的试验研究

介绍了水力空化作用机理,研究了水力空化作用对褐煤水煤浆粘度的影响,探讨了空化后浆体内存在气泡的形态及影响关系。试验结果表明:水力空化处理后的水煤浆浆体流动性变好,水煤浆的粘度特性已由假塑性流体变成了类似牛顿流体;速度梯度为100 s-1时的粘度指标由320 mPa·s提高到340 mPa·s,速度梯度为30 s-1时的粘度指标由420 mPa·s提高到850 mPa·s,30μm以下的细粒级含量明显高于空化前粒级的含量;水力空化作用在水煤浆中引入了大量不易消失的圆形微细气泡,气泡的占位作用提高了水煤浆粘度和稳定性,微细气泡的布朗运动破坏了颗粒之间的静电力吸附,圆形微细气泡成为水煤浆浆体流动过程中的润滑剂并改善水煤浆流变性能。

Experimental study on the influence of hydrodynamic cavitation on the rheological characteristics of lignite coal water slurry

The mechanism of hydrodynamic cavitation was introduced.Its influence on the viscosity of lignite coal water slurry(CWS)was studied Then the morphology of air bubbles in the slurry after cavitation and its impacts were discussed.The experimental results show that,after hydrodynamic cavitation,the fluidity of CWS becomes better.The viscosity of CWS changes from pseudoplastic fluid to Newtonian fluid.The viscosity of CWS increases from 320 mPa·s to 340 mPa·s at a speed gradient of 100 s-1,and from 420 mPa·s to 850 mPa·s at a speed gradient of 30 s-1.The content of fine coal particles under 30μm increases significantly.Hydrodynamic cavitation introduce a lot of small air bubbles into CWS which can exist for a long time and increase the viscosity and stability of CWS.The Brownian motion of the fine bubbles destroys the electrostatic adsorption between particles and become a kind of lubricant in the flow process,thus the rheological property of CWS is improved.