[1] Zhao Changsui, Liang Cai, Chen Xiaoping, Pu Wenhao, et al. Flow characteristics and Shannon entropy analysisof dense-phase pneumatic conveying under high pressure [J]. Journal of Southeast University (English Edition), 2007, 23 (4): 609-614. [doi:10.3969/j.issn.1003-7985.2007.04.026]
Copy
Flow characteristics and Shannon entropy analysisof dense-phase pneumatic conveying under high pressure(
)
高压浓相粉煤气力输送特性及信息熵分析
)Journal of Southeast University (English Edition)[ISSN:1003-7985/CN:32-1325/N]
- Volumn:
- 23
- Issue:
- 2007 4
- Page:
- 609-614
- Research Field:
- Chemistry and Chemical Engineering
- Publishing date:
- 2007-12-30
Info
- Title:
- Flow characteristics and Shannon entropy analysisof dense-phase pneumatic conveying under high pressure
- 高压浓相粉煤气力输送特性及信息熵分析
- Author(s):
- Zhao Changsui, Liang Cai, Chen Xiaoping, Pu Wenhao, Lu Peng, Fan Chunlei
- Key Laboratory of Clean Coal Power Generation and Combustion Technology of Ministry of Education, Southeast University, Nanjing 210096, China
- 气力输送; 高压; 浓相; 固气比; Shannon信息熵
- PACS:
- TQ051
- DOI:
- 10.3969/j.issn.1003-7985.2007.04.026
- Abstract:
- Experiments of dense-phase pneumatic conveying of pulverized coal using nitrogen are carried out in an experimental test facility with the conveying pressure up to 4.0 MPa and the gas-solid ratio up to 450 kg/m3.The influences of different conveying differential pressures, coal moisture contents, gas volume flow rates and superficial velocities on the solid-gas ratios are investigated.Shannon entropy analysis of pressure fluctuation time series is developed to reveal the flow characteristics.Through investigation of the distribution of the Shannon entropy under different conditions, the flow stability and the evolutional tendency of the Shannon entropy in different regimes and regime transition processes are discovered, and the relationship between the Shannon entropy and the flow regimes is also established.The results indicate that the solid-gas ratio and the Shannon entropy rise with the increase in conveying differential pressure.The solid-gas ratio and the Shannon entropy reveal preferable regularity with gas volume flow rates.The Shannon entropy is different for different flow regimes, and can be used to identify the flow regimes.Both mass flow rate and the Shannon entropy decrease with the increase in moisture contents.The Shannon entropy analysis is a feasible approach for researching the characteristics of flow regimes, flow stability and flow regime transitions in dense-phase pneumatic conveying under high pressure.
- 在输送压力可达4.0 MPa, 固气比高达450 kg/m3的高压气力输送试验台上, 用氮气进行粉煤高压浓相气力输送试验研究.分别在不同的输送差压、煤粉湿度、浓度和速度等条件下进行了输送试验, 考察操作参数对煤粉固气比等气力输送特征参数的影响, 用信息熵分析试验过程中采集到的压力波动时间序列, 探讨流动稳定性和流型变迁过程中信息化趋势, 建立信息熵和流型之间的关系.结果表明:在输送差压增大的过程中, 固气比和Shannon信息熵均增大;气体流量与Shannon信息熵和固气比之间呈现较好的规律性;不同流动形态的Shannon熵差异较大, 不同流型之间的Shannon熵区分度较好.随着煤粉湿度的增大, 煤粉质量流量和Shannon熵均降低.Shannon信息熵分析为研究高压浓相气力输送流型、流动稳定性及其转变特性提供了一种行之有效的方法.
References:
[1] Shen Xianglin, Xiong Yuanquan.Experimental study on dense-phase pneumatic conveying of pulverized coal at high pressures[J].Proceedings of the CSEE, 2005, 25(24):103-107.(in Chinese)
[2] Molerus O.Overview:pneumatic transport of solids[J].Powder Technology, 1996, 88(3):309-321.
[3] Wypych P W, Yi J.Minimum transport boundary for horizontal dense-phase pneumatic conveying of granular materials[J].Powder Technology, 2003, 129(1/2/3):111-121.
[4] Gong Xin, Guo Xiaolei, Feng Jinhua, et al.High solids loading pneumatic conveying of pulverized coal[J].Journal of Chemical Industry and Engineering, 2006, 57(3):640-644.(in Chinese)
[5] Laouar S, Molodtsof Y.Experimental characterization of the pressure drop in dense phase pneumatic transport at very low velocity[J].Powder Technology, 1998, 95(2):165-173.
[6] Jama G A, Klinzing G E, Rizk F.An investigation of the prevailing flow patterns and pressure fluctuation near the pressure minimum and unstable conveying zone of pneumatic transport systems[J].Powder Technology, 2000, 112(1/2):87-93.
[7] van der Schaaf J, van Ommen J R, Taken F, et al.Similarity between chaos analysis and frequency analysis of pressure fluctuations in fluidized beds[J].Chemical Engineering Science, 2004, 59(8/9):1829-1840.
[8] Zhong Wenqi, Zhang Mingyao.Pressure fluctuation frequency characteristics in a spout-fluid bed by modern ARM power spectrum analysis[J].Powder Technology, 2005, 152(3):52-61.
[9] Hay J M, Nelson B H, Briens C L, et al.The calculation of the characteristics of chaotic attractor in a gas-solid fluidized bed[J].Chemical Engineering Science, 1995, 50(3):373-380.
[10] Huang Z, Wang B, Li H.Application of electrical capacitance tomography to the void fraction measurement of two-phase flow[J].Transactions on Instrumentation and Measurement, 2003, 52(3):7-12.
[11] Li Hui.Application of wavelet multi-resolution analysis to pressure fluctuations of gas-solid two-phase flow in a horizontal pipe[J].Powder Technology, 2002, 125(1):61-73.
[12] Wu H, Zhou F, Wu Y.Intelligent identification system of flow regime of oil-gas-water multiphase flow[J].International Journal of Multiphase Flow, 2001, 27(3):459-475.
[13] Cho Y J, Kim S J, Nam S H, et al.Heat transfer and bubble properties in three-phase circulating fluidized beds[J].Chemical Engineering Science, 2001, 56(21/22):6107-6115.
[14] Zhong Wenqi, Zhang Mingyao.Characterization of dynamic behavior of a spout-fluid bed with Shannon entropy analysis[J].Powder Technology, 2005, 159(3):121-126.
[15] Wang X, Zhen L, Hang H, et al.Research on pressure fluctuations time serials by deterministic chaos theory and information entropy[J].Chinese Journal of Scientific Instrument, 2002, 23(6):596-599.(in Chinese)
[16] Shi L, Zhang Z, Yang R.Shannon entropy characteristics of air-water two phase flow regimes in vertical pipes[J].Nuclear Power Engineering, 2000, 21(5):411-415.(in Chinese)
[17] Hillborn R C.Chaos and nonlinear dynamics[M].New York:Oxford University Press, 1994.
[18] Hong J, Shen Y, Tomita Y.Phase diagram in dense phase pneumatic transport[J].Powder Technology, 1995, 84(3):213-219.
Memo
- Memo:
- Biography: Zhao Changsui(1945—), male, professor, cszhao@seu.edu.cn.