渣浆泵临界流速和管路摩阻系数研究简况

管道水力输送中最重要一个参数就是管道输送固体物料的临界流速。国内外研究人员对这个问题进行了大量试验研究工作，提出了不同形式的临界流速表达式。
  一、临界流速
    临界流速是判断管路中是否发生堵塞重要尺度之一，管中平均流速要大于临界流速才发生堵塞现象。
  1.杜拉德公式
 1952年，杜拉德等根据砂浆和煤浆的管道试验结果提出下列公式
     

2.凯夫公式
 凯夫等人提出下列临界流速公式

3. 何希杰公式

1986年，何希杰在研究凯夫公式基础上，提出下列改进公式

二、管道摩擦阻力系数

  在计算渣浆泵清水等径管路水头损失时，采用达西公式。对公示中摩擦阻力系数f，国内外研究人员进行了大量研究工作，提出一批研究成果。

1. 科尔布鲁克-怀特公式

公式是以隐函数形式给出的，给计算工作带来不便。因此，国内外研究人员对这个公式进行研究，提出一些简化公式。

2.莫迪近似公式

3.斯瓦斯公式

4.阿尔特苏利公式

5.何希杰、窦以松公式

何希杰、窦以松分别于1992年和1995年研究分析，通过大量计算后提出简化公式

 同时给出了常温清水时钢管和铸铁管的摩擦阻力系数公式，分别为

何希杰、窦以松提出的简化公式计算精度，在工程使用范围内均高于现有简化公式

Research on Critical Flow Velocity and Pipeline Friction Coefficient of Slurry Pump

One of the most important parameters in pipeline hydraulic transportation is the critical flow rate of solid materials in pipeline transportation. Researchers at home and abroad have done a lot of experimental research on this problem, and put forward different e­xpressions of critical velocity.

I. Critical Flow Velocity

Critical flow velocity is one of the important criteria to judge whether blockage occurs in pipelines. The blockage occurs only when the average flow velocity in pipelines is greater than the critical flow velocity.

1. Durad formula

In 1952, Durad et al. proposed the following formulas based on the results of pipe tests of mortar and coal slurry.

2. Cave's formula

Kev et al. proposed the following critical velocity formulas

3. He Xijie Formula

In 1986, Ho Xijie proposed the following improved formulas on the basis of researching the Kev formula.

2. Friction Resistance Coefficient of Pipeline

Darcy's formula is used in calculating head loss of clean water pipeline of slurry pump. A lot of research work has been done on the coefficient f of friction resistance in the publication, and a number of research results have been put forward.

1. Colbrooke-White Formula

The formula is given in the form of implicit function, which brings inconvenience to the calculation. Therefore, researchers at home and abroad have studied this formula and put forward some simplified formulas.

2. Moody's approximation formula

3. Swas Formula

4. Altsuli Formula

5. He Xijie's and Dou Yisong's formulas

He Xijie and Dou Yisong studied and analyzed in 1992 and 1995 respectively, and put forward simplified formulas after a large number of calculations.

At the same time, the friction coefficient formulas of steel pipe and cast iron pipe at normal temperature and clean water are given.

The calculation accuracy of the simplified formulas proposed by He Xijie and Dou Yisong is higher than that of the existing simplified formulas in the scope of Engineering application.