涡流空气分级机熵产与分级性能分析

doi:10.16085/j.issn.1000-6613.2020-0026

摘要/Abstract

摘要：

利用热力学第二定律中的熵产理论对涡流空气分级机各不可逆因素引起的熵产进行分析，通过粉料分级试验对其分级性能进行验证，获得了黏性熵产、湍流熵产和壁面熵产分布特点及操作参数对熵产和分级精度的影响规律。熵产分析结果表明，涡流空气分级机内湍流熵产和壁面熵产占总熵产的比例高达56.41%和43.11%，湍流熵产主要产生于转笼叶片间和转笼内部，进风口和细粉出口壁面剪切引起较大壁面熵产；此外，转笼转速和进口风速变化分别仅对转笼区域和切向进风口区域内气流运动熵产影响较大，进口风速-转笼转速处于8.6m/s、 800r/min和18m/s、1200r/min操作工况附近时，涡流空气分级机内总熵产/总能变化率较小，分级流场稳定性较高，对粗、细颗粒分离有利，该工况下分级机的粉料分级试验效果较好，说明熵产理论可用于涡流分级机内流动分析及其操作参数的优化匹配。

关键词: 粉体技术, 涡流空气分级机, 熵产分析, 操作参数, 分级性能

Abstract:

The entropy production theory in the second law of thermodynamics was used to analyze the entropy generation caused by the irreversible factors in turbo air classifier. The classification performance of the turbo air classifier was evaluated by powder classification experiments. The entropy generation caused by gas viscosity, turbulent and wall fraction were obtained. Meanwhile, the effects of operational parameters on entropy generation and classification performance were investigated. The results showed that the ratios of turbulent entropy generation and wall entropy generation to total entropy generation were 56.41% and 43.11%, respectively. The turbulent entropy generation mainly occurred in the blade clearance and the inner rotor cage, while the wall entropy was mainly caused by walls of the air inlet and outlet. The rotor cage speed and inlet air velocity dominated the gas entropy generation in the regions of the rotor cage and air inlet, respectively. The variation of the entropy generation/total energy in the classifier was insignificant and the stability of the flow field was high when the classifier worked on the conditions of 8.6m/s-800r/min and 18m/s-1200r/min, respectively. In this case, the flow field distribution was helpful for particle separation and the classifier had higher classification efficiency. Therefore, the entropy generation analysis can be used for the prediction of the flow characteristics and operational optimization of the air classifier.

Key words: powder technology, turbo air classifier, entropy generation analysis, operational parameters, classification performance

中图分类号:

TH 3

孙占朋, 梁龙龙, 刘春雨, 于新奇, 杨光. 涡流空气分级机熵产与分级性能分析[J]. 化工进展, 2020, 39(10): 3909-3915.

Zhanpeng SUN, Longlong LIANG, Chunyu LIU, Xinqi YU, Guang YANG. Analysis of entropy generation and classification performance of turbo air classifier[J]. Chemical Industry and Engineering Progress, 2020, 39(10): 3909-3915.

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