Based on existing wall surface model and particle kinetics, a new model of multiphase flow was set up for high-pressure dense-phase pneumatic conveying of pulverized coal in an integrated pipe (vertical pipe, elbow and horizontal pipe connected together) with nitrogen as the carrying medium, by adequately considering the impact of friction stress on the gas-solid two-phase flow. The model was used to simulate the flow characteristics of gas-solid two-phase flow in an integrated pipe, so as analyze the effects of supplementary air flow on the solid-phase velocity, concentration and distribution of turbulent kinetic energy as well as the elbow pressure drop. Results show that the error of elbow pressure drop between simulation results and experimental data is reduced to be less than 20%, verifying the correctness of the model; with the rise of supplementary air flow, the elbow pressure drop increases first and decreases later on, resulting in increased superficial gas velocity, reduced accumulation of pulverized coal on outer side of elbow surface, increased low density area, and increased solid-phase turbulent kinetic energy and granular temperature; when the supplementary air flow gets up to 1.0 m3/h, both the solid-phase turbulent kinetic energy and the granular temperature reduce.
Key words
vertical elbow /
pneumatic conveying /
friction stress /
numerical simulation
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References
[1] 蒲文灏,赵长遂.水平管加压密相煤粉气力输送沙丘流的数值模拟[J].动力工程学报, 2011,31(2): 120-126.
PU Wenhao, ZHAO Changsui.Numerical simulation on dune flow in pressurized dense phase pneumatic conveying of pulverized coal in horizontal pipe[J].Journal of Chinese Society of Power Engineering,2011, 31(2): 120-126.
[2] 蒲文灏,赵长遂,熊源泉,等.垂直管密相输送的数值模拟[J].动力工程, 2008, 28(1): 95-99.
PU Wenhao, ZHAO Changsui, XIONG Yuanquan, et al.Numerical simulation of the dense phase conveying in vertical pipe[J].Journal of Power Engineering, 2008, 28(1): 95-99.
[3] MCGLINCHEY D, COWELL A, KNIGHT E A, et al.Bend pressure drop predictions using the Euler-Euler model in dense phase pneumatic conveying[J].Particulate Science and Technology, 2007, 25(6): 495-506.
[4] MA A C, WILLIAMS K C, ZHOU J M, et al.Numerical study on pressure prediction and its main influence factors in pneumatic conveyors[J].Chemical Engineering Science, 2010, 65(23): 6247-6258.
[5] VASHISTH S, GRACE J R.Simulation of granular transport of Geldart type-A, -B, and -D particles through a 90° elbow[J].Industrial & Engineering Chemistry Research, 2012, 51(4): 2030-2047.
[6] GIDASPOW D, JUNG J, SINGH R K.Hydrodynamics of fluidization using kinetic: an emerging paradigm 2002 flour-daniel lecture[J].Powder Technology, 2004,148(2):123-141.
[7] LU H L, GIDASPOW D, BOUILLARD J, et al.Hydrodynamic simulation of gas-solid flow in a riser using kinetic theory of granular flow[J].Chemical Engineering Journal, 2003, 95(1/2/3): 1-13.
[8] PU W H, ZHAO C S, XIONG Y Q, et al.Three-dimensional numerical simulation of dense pneumatic conveying of pulverized coal in a vertical pipe at high pressure[J].Chemical Engineering & Technology, 2008, 31(2): 215-223.
[9] JENKINS J T, SAVAGE S B.A theory for the rapid flow of identical, smooth, nearly, elastic spherical particles[J].J Fluid Mech, 1983, 130(5): 187-202.
[10] JOHNSON P C, JACKSON R.Frictional-collisional constitutive relations for granular materials, with application to plane shearing[J].J Fluid Mech,1987, 176(9): 67-93.
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