以细颗粒浆液为载体的固液两相流管道输送研究

Solid-liquid two phase flows in pipelines can be classified into homogeneous flow, pseudo-homogeneous flow, and heterogeneous flow. The heterogeneous flow can be further divided into one with water as conveying media and another with fine particle slurry (no settling) as conveying media. The later type of two phase flow is selected in this project to study the properties and their effects on the pipeline transport parameters. The formation of such type of solid-liquid two phase flow is mainly related to the properties of the solid granulated material it carries. The homogeneous flow contains only fine particles that are difficult to settle. The pseudo-homogeneous flow contains mainly fine particles but with a small amount of medium and coarse particles. The heterogeneous flow contains a large amount of fine particles and a certain amount of coarse particles; the gap-graded gradation is a typical composition, which contains no the medium particles. For this type of flow, the rheological properties and the settling characteristics are different from those of the homogeneous and pseudo-homogeneous flows. In addition, the transport parameter, resistance loss, critical transport velocity, and even the transitional process of restarting from accident pump stopping are different from those in ordinary solid-liquid two phase flows due to the settling of coarse particles. Experimental study focusing on these problems will be conducted in this project. Objectives are to examine the effects of fine and coarse material contents on the rheological properties and transport characteristics of solid-liquid two phase flows in pipelines.

固液两相流可以分为均质流、伪均质流、非均质流，非均质流又分为以水为载体和以细颗粒浆液（基本不沉）为载体的两相流。本项目主要研究后一种，以细颗粒浆液为载体的两相流的特性及对管道输送参数的影响。.只所以形成这种固液两相流，主要与固液两相流中所含的固体粒状物料有关。而两相流均质流所含都是难沉的细颗粒，伪均质流主要含有细颗粒也有少量中粗颗粒，以细颗粒浆液为载体的非均质流，即含有大量细颗粒，也含有一定数量的粗颗粒，最典型的是断开级配，即有大量细颗粒，又含有一定量粗颗粒，而不含中间颗粒的固液两相流。这种两相流其流变特性，沉降特性都不同于均质流或伪均质流。另外，在管道输送过程颗粒运动规律，其输送参数：阻力损失，输送临界流速，甚至事故停泵再起动的过渡过程，由于粗颗粒下沉不同于一般固液两相流。本项目主要针对以上问题开展实验研究。得到细、粗颗粒不同含量等因素对固液两相流特性及管道输送特性的影响。