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渣漿泵臨界流速和管路摩阻系數研究簡況

管道水力輸送中最重要一個參數就是管道輸送固體物料的臨界流速。國內外研究人員對這個問題進行了大量試驗研究工作，提出了不同形式的臨界流速表達式。
  一、臨界流速
    臨界流速是判斷管路中是否發生堵塞重要尺度之一，管中平均流速要大于臨界流速才發生堵塞現象。
  1.杜拉德公式
 1952年，杜拉德等根據砂漿和煤漿的管道試驗結果提出下列公式
     

2.凱夫公式
 凱夫等人提出下列臨界流速公式

3. 何希杰公式

1986年，何希杰在研究凱夫公式基礎上，提出下列改進公式

二、管道摩擦阻力系數

  在計算渣漿泵清水等徑管路水頭損失時，采用達西公式。對公示中摩擦阻力系數f，國內外研究人員進行了大量研究工作，提出一批研究成果。

1. 科爾布魯克-懷特公式

公式是以隱函數形式給出的，給計算工作帶來不便。因此，國內外研究人員對這個公式進行研究，提出一些簡化公式。

2.莫迪近似公式

3.斯瓦斯公式

4.阿爾特蘇利公式

5.何希杰、竇以松公式

何希杰、竇以松分別于1992年和1995年研究分析，通過大量計算后提出簡化公式

 同時給出了常溫清水時鋼管和鑄鐵管的摩擦阻力系數公式，分別為

何希杰、竇以松提出的簡化公式計算精度，在工程使用范圍內均高于現有簡化公式

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.