渣浆泵悬浮液的流动特点
 一、悬浮液流动特点
  下面研究悬浮液的流动，其流变特性遵守公式(2-1-1)所描述的规律。悬浮液在压降引起的摩擦应力t (或者管壁面切应力)未达到确定值0之前是固定的。当r≥0时，在壁面上开始形成一定厚度的液体活动层。
  圆管中切应力r按线性规律分布，即tR=z,R/r [式中，TR和r.分别为管壁面(半径为R)和有效半径r上的应力]，随者中心到管联面的半径增大而增大(与流动特性无关)。因此，在半径r值得小时，r<0， 悬浮液是不动的，而半径很大时，r≥0，悬浮液开始流动。在悬浮液开始流动后，当半径很大时，在压降作用下，整个悬浮液都运动。同时在管壁面上产生切应力tR，在确定半径(用ro表示)上产生应力日。如果用L0表示半径为ro的圆柱体表面上流动速度，那么可以说位于离中心距离小于To处的所有其余液体层，将以同样速度mo运动。这样在管中心就形成运动悬浮液所包用的具有不破环结构的半径为n的四柱体(称为流动核》 对于这种情况。切应力-0Fphl/dr (图2-2 43. 在流动核和管使面之间层内，应力大于技内应力，巡度小于核内速度。因此，核的速度同时是流体最大度，山uu/dr在选用的坐标系中为负值。因为半径 ,减小dr,液体层运动速度增大du,比值d根据式(2-1-1)，悬浮液在所谓液体层中流动速度变化

由此可以认为，在管壁面上流动速度等于零，
二、白金汉方程

可塑液流核应力增大时，在其表面开始破坏和黏性为的液体层将增大。以速度u运动的液流核开始变厚。在极限情况下，压降相当大，因而悬浮液流动速度相当大，液流核完全被破坏，从层流转变为絮流状态。在塑性核表面上应力减少时，其部分结构恢复，在核和管整之间液体层减薄。这样，可塑层半径为
 

当压降变为零时，等式第一项变为零，悬浮液流动将停止。等式右边等三项随着压降增大而迅速减小。
    如果结构完成破坏的悬浮液对不动固体绕流或者被挡住，那么液流变慢。同时，在绕流物体附近，由于速度局部变慢，可能形成结构不破坏的液体层。与牛顿体液流对物体绕流条件相比，其物体绕流条件有明显变化。具有流动结构状态的悬浮液层(连续有破坏结构)，也称为宾汉体，只有接近绕流物体，不论在其前面或者在其表面上，渣浆泵液体其余部分将具有完全破坏的结构。

Flow characteristics of slurry pump suspension

I. Flow characteristics of suspension

Next, the flow of suspension is studied. The rheological properties of suspension follow the rules described in formula (2-1-1). The suspension is fixed before the frictional stress t (or the wall shear stress) caused by the pressure drop does not reach the determined value of 0. When R is greater than or equal to 0, a liquid active layer with a certain thickness begins to form on the wall.

The distribution of shear stress r in a circular pipe is linear, i.e. tR=z, R/r [in the formula, TR and R. are stresses on the wall (radius R) and effective radius r, respectively], which increase with the increase of the radius from the center to the joint (independent of the flow characteristics). Therefore, when the radius R is small, r < 0, the suspension is immobile, and when the radius is large, r < 0, the suspension begins to flow. After the suspension begins to flow, when the radius is large, the whole suspension moves under the action of pressure drop. At the same time, the shear stress tR is generated on the wall of the pipe, and the stress day is generated on the determined radius (expressed by ro). If L0 is used to represent the velocity of flow on the surface of a cylinder with radius ro, it can be said that all the remaining liquid layers located at a distance less than to the center will move at the same velocity mo. In this way, a four-cylinder with a radius of n (called a flow core) enclosed in a moving suspension is formed at the center of the tube. Shear stress-0Fphl/dr (Fig. 2-243). In the layer between the flow core and the tube, the stress is greater than the technical stress and the patrol is less than the velocity in the core. Therefore, the velocity of the core is the maximum of the fluid at the same time, and Shanuu/dr is negative in the selected coordinate system. Because the radius decreases and the Dr increases, the velocity of liquid layer increases du. The ratio D varies according to formula (2-1-1), and the velocity of suspension in the so-called liquid layer varies.

It can be concluded that the velocity of flow on the wall of the pipe is equal to zero.

2. Buckingham equation

When the core stress of plastic fluid flow increases, the liquid layer which begins to destroy on its surface and has viscous properties will increase. The liquid core moving at velocity u begins to thicken. In the extreme case, the pressure drop is quite large, so the suspension flow velocity is quite large, and the core of the liquid flow is completely destroyed, which changes from laminar flow to flocculation state. When the stress on the plastic core surface decreases, part of its structure restores and the liquid layer between the core and the tube becomes thinner. In this way, the radius of the plastic layer is

When the pressure drop becomes zero, the first term of the equation becomes zero and the suspension flow stops. The three terms on the right side of the equation decrease rapidly with the increase of pressure drop.

If the suspension is blocked or flowed around the immobile solid after the structure is destroyed, the fluid flow is slow. At the same time, near the flow object, due to the local slowdown of velocity, a liquid layer with structural damage may be formed. Compared with Newton's fluid flow, the fluid flow around an object has obvious changes. The suspension layer with flowing structure (continuous destructive structure), also known as Bingham body, is only close to the object around it. No matter in front of it or on its surface, the rest of the liquid will have completely destructive structure.