前沿

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Front

Focus

. 16 .

World Pulp and Paper Vol. 27, No. 1

-low predictability of results

-risk for a deposit generator

2　Mixing of the additives with
advanced Transverse mixing

To make an improvement into

this part of the process good and fast

mixing plays an important role. Wetend

Technologies Ltd has developed a

TrumpJet mixing technology and

about 200 mixing stations today is in

use for various additives in paper and

board mills globally. Mixing exploits

circulated headbox stock to mix the

additive fast, gentle and efficiently.

Technology is based on advanced

Transverse jet mixing with high mixing

intensity.

2.1

　Transverse mixing

T r a n s v e r s e m i x i n g i s n o t

c o m m o n l y w e l l k n ow n i n d e t a i l .

Conventional way to dose additives into

the process imitates often the transverse

mixing process, but injection energy or

intensity and volume of fl ow is so small

that true mixing never can happen.

Recently the mixing phenomena have been studied more in detail.

The transverse mixing process, when well designed and developed, is

a very powerful and effi cient mixing process. The mixing takes place

effi ciently in several steps in the transverse mixing process. Figure 2

shows the transverse jet penetrating upward into cross flow making

headway from left to right.

Among the important physical phenomena associated with the

transverse jet is a formation of different kinds of vortical structures

following the influence of the cross flow (stock heading towards

headbox):

① The counterrotating vortex pair (CVP) , which results

in a complex interaction between jet fl ow and ambient cross fl ow,

②

Jet shear layer vortices

③ Horseshoe vortices and ④ Wake structures

and vortices. The CVP is a very robust feature of the transverse jet;

it is seen to have a very important role in enhancing mixing between

jet and cross flow. The horseshoe vortex and wake structures are

interactions of the jet with pipe wall boundary layers. It develops

mixing of fl ows also between the pipe wall and CVP.

The above makes it possible to mix the chemical quickly into

the cross flow and to cover completely quickly and efficiently the

whole cross area on the main process pipe. Figure 4 shows a computer

fl ow modeling results for a core part of the counter rotating vortex pair

in a stock pipe generated by a TrumpJet mixer.

2.2

　Mixing result in a headbox feed pipe – TrumpJet Flash Mixing

A computer simulation of transverse mixing of four TrumpJets

in a pipe of 800 mm is presented in fi gure . The results are as follows:

　先进的横断添加剂混合原理

解决工艺过程中的上述问

题，高效快速的混合扮演了重
要角色。温德造纸湿部技术公
司开发了一种创捷混合技术，
如今已有 200 套创捷混合系统
在世界各种纸机和纸板机上运
行，混合各种不同的添加剂。

混合开发了采用以流浆箱浆料
循环作为添加剂的介质，混合
快速温和且高效。技术上基于
先进的高强度的横断喷射混合
技术。
2.1

　横断混合

横断混合是一种不为人知

非常规的混合方式。传统的添
加剂混合方法经常效仿横断混
合，但喷射能量或强度及体积、
流量均太小以至于真正的混合
根本就没有发生。近来，混合

现象的研究越来越趋于对细节的研究，横断混合的过
程就这样被设计并开发，是一种非常强有力而高效的
混合工艺，横断混合在几个混合工艺阶段发生。图 2
描述了从左到右横断喷射流态向上横流进展的情况。

关于横断混合喷射的重要物理现象是由交叉流动

（浆料流向流浆箱）形成的各种涡流结构：① 对流涡

流对（CVP），产生于喷射流和周围横流的交感作用；
② 喷射剪切涡流；③ 马蹄涡流；④ 激发结构及涡流。
CVP

是一种非常激烈的横断喷射作用，被认为是增强

射流和横流强度的重要角色。马蹄涡流和激发结构是
射流与管壁分界限交感的结果，它使混合发生在管壁
和 CVP 之间。

上述原理使得化学品快速与横流混合，并且集完

整、快速、高效于一体在主工艺管路整个横断面混合。
图 3 所示为计算机流态模型。
2.2

　创捷瞬时混合在流浆箱管中的效果

计算机模拟的 4 个创捷横断混合用于管径为

800 mm

的管，其结果见图 4。① 喷入点 1 m 后：对

流涡流对已经形成；② 喷入 1 s 后：化学品在管路横
断面分布开来，管路断面各个角落已经有化学品分布；
③喷入 2 s 后：化学品已经很好地分布在管路的横断

Figure 3　A core part of the counter rotating vortex

pair (CVP) in a stock pipe generated by a TrumpJet

mixer presented by computer graphics injection

图 3　创捷混合器在浆管中产生的对流涡流对

（CVP）计算机制图

管径

400mm

单一创捷

个创捷

A.One single TrumpJet

B.Four TrumpJets Eight CVP

管径800mm

Figure 2　Four powerful mixing tools of a transverse jet

图 2　4 种横断喷射强有力的混合工具

剪切涡流

马蹄涡流

对流涡流对

1.Counter vortex pair (CVP)

2.Shear layer vertex

4.Wake vortes region

3.Horseshoe vortex region

激发涡流