Abstract:

Headbox is a critical part of paper machine. The formation property of paper is greatly influenced by headbox performance. In hydraulic headbox, a stilling chamber is used as a rectifier of pulp flow. Submerged jet in stilling chamber renders pulp flow an even velocity profile. The length of stilling chamber is a key parameter. Based on the realizable k-ε turbulent model, the flow field of stilling chamber in hydraulic headbox was numerically simulated with software Fluent. The results of numerical simulation were verified by PIV, and the measurement results agreed well with the numerical results. Statistical theory was used to calculate the standard deviation of flow velocity on the cross sections of stilling chamber. The value of standard deviation was used to evaluate the uniformity of flow velocity. The length of stilling chamber(L)was calculated at different values of manifold tube diameter(d)and inlet velocity(v). The results showed that L increased linearly with increasing d and v. Binary function was used to fit the relationship between L and d, v. The function could be used as a reference for designing stilling chamber of hydraulic headbox.

Key words: FONT-SIZE: 10.5pt, mso-ascii-font-family: Times New Roman, mso-bidi-font-family: Times New Roman, mso-font-kerning: 1.0pt, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, mso-bidi-language: AR-SA">水力式；流浆箱；管束；稳流室；数值模拟

摘要：

流浆箱是造纸机上非常关键的设备，纸页的成形质量很大程度上取决于流浆箱的性能。水力式流浆箱采用稳流室作为浆料匀整装置，利用淹没射流原理，使流浆箱内的浆流具有均匀的速度剖面。稳流室长度是稳流室的一个非常重要的参数。基于可实现k-ε湍流模型，运用Fluent求解水力式流浆箱稳流室内的流场参数，利用PIV测量技术对数值模拟结果进行验证，测量结果与数值模拟结果吻合良好。利用统计学原理计算出稳流室各横截面上的速度均方差，并以速度均方差值的变化趋势来判断稳流室内浆流速度是否达到均匀，对于不同布浆管束直径d和浆料入射速度v，计算出稳流室内浆流达到均匀分布所要求的长度L，结果表明L值随着布浆管束的直径增加和入射速度的提高而增大，并且二者分别符合一次函数关系。利用二元函数拟合得出L值与d和v之间的关系式，该式可作为水力式流浆箱稳流室的设计参考。

关键词: FONT-SIZE: 10.5pt, mso-ascii-font-family: Times New Roman, mso-bidi-font-family: Times New Roman, mso-font-kerning: 1.0pt, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, mso-bidi-language: AR-SA">水力式；流浆箱；管束；稳流室；数值模拟