Numerical investigation on flow and heat transfer performance of gravity-driven granular flowing across inverted drop-shaped tube

doi:10.11949/0438-1157.20190557

Abstract

Abstract:

Gravity-driven granular flowing across inverted drop-shaped tubes is investigated, with the aim to enhance flow and heat transfer performance and avoid particle stagnant. The discrete element method was used to simulate the flow and heat transfer of a gravity-driven particle flow across a circular tube and a drop-shaped tube with different ellipticities (e= 1.0, 1.5, 2.0, 2.5) was analyzed.t The effect of ellipticity on the size of the stagnation zone, the normal and tangential force on the pipe, and the effective heat transfer coefficient was compared with the circular tube. The main conclusions are as follows: compared with circular tube, granular flow drop-shaped tubes perform better in flow and stagnation avoidance. The stagnation area and the void area of the drop-shaped tube are smaller than the circular tube. As the ellipticity increases, the particle flow velocity at the top of the tube increases, and the flow upward the tube becomes better. The drop-shaped tube is subjected to the normal force and the tangential force of the granular flow and both are smaller than the circular tube. After the ellipticity is more than 1.0, the ellipticity is increased, and the two forces are no longer reduced. The effective heat transfer coefficient of the drop-shaped tube is smaller than that of the circular tube, and the effective heat transfer coefficient decreases as the ellipticity increases.

Key words: particle process, granular flow heat transfer, discrete element method, drop-shaped tube, numerical investigation, moving bed

摘要：

采用离散单元方法（DEM）模拟了重力驱动的颗粒流横掠圆管和不同椭圆度（e=1.0,1.5,2.0,2.5）的滴形管下的流动与换热情况，分析了滴形管的椭圆度对停滞区大小、管周受力以及有效传热系数的影响，并与圆管进行了对比。主要结论如下：滴形管的停滞区和空区均小于圆管，随着椭圆度增大，管顶部颗粒流速增加，流动性变好；滴形管受颗粒流的法向力和切向力均小于圆管，在椭圆度大于1.0后，增加椭圆度，两力不再减小；滴形管的有效传热系数小于圆管，且随着椭圆度增大，有效传热系数降低。

关键词: 颗粒过程, 颗粒流传热, 离散单元法, 滴形管, 数值研究, 移动床

CLC Number:

TQ 025.2

Zhoutuo TAN,Zhigang GUO,Jian YANG,Qiuwang WANG. Numerical investigation on flow and heat transfer performance of gravity-driven granular flowing across inverted drop-shaped tube[J]. CIESC Journal, 2019, 70(S2): 94-100.

谈周妥,郭志罡,杨剑,王秋旺. 重力驱动颗粒流横掠倒置滴形管管外流动传热特性的数值研究[J]. 化工学报, 2019, 70(S2): 94-100.

Figures/Tables 15

Fig.1 Granular flow around circular tube

Fig.2 Geometry model

Table 1 Geometry parameters of drop-shaped tube

e	a/mm	b/mm
0(圆管)	10	10
1.0	11.02816	7.79809
1.5	11.65153	6.463104
2.0	12.13529	5.427069
2.5	12.13529	4.642921

Fig.3 Geometrical parameters of drop-shaped tube

Fig.4 Model validation

Table 2 Geometry parameters

H ₁/mm	H ₂ /mm	H ₃ /mm	L/mm	T _wall/K	k _t/(W?m^-1?K^-1)
40	10	160	10	287	15.0

Table 3 Physical properties of particles

d _p/mm	ρ/(kg·m^-3)	c_p /(J?kg^-1·K^-1)	k _p/(W?m^-1·K^-1)
0.2	2600	1600	2.5

Table 4 Boundary conditions

u _m/(mm·s^-1)	T _in/K	T _wall/K	其余壁面
5	1000	287	绝热

Fig.5 Velocity distribution of circular tube and drop-shaped tube

Fig.6 Selection of statistical regions

Fig.7 Average particle velocity in various ellipticities

Fig.8 Heat transfer coefficient in different ellipticities

Fig.9 Average contact number in different ellipticities

Fig.10 Tangential force in different elliptcities

Fig.11 Normal force in different elliptcities

References 14

1	Zhang H , Wang H , Zhu X , et al . A review of waste heat recovery technologies towards molten slag in steel industry[J]. Applied Energy, 2013, 112(4): 956-966.
2	郑斌, 刘永启, 李瑞阳, 等 . 高温煅烧石油焦排料过程余热回收[J]. 化工进展, 2015, 34(6): 1539-1543.
	Zheng B , Liu Y Q , Li R Y , et al . Experimental investigation on waste heat reutilization of calcined petroleum coke[J]. Chemical Industry and Engineering Progress, 2015, 34(6): 1539-1543.
3	Liu J , Yu Q , Peng J , et al . Thermal energy recovery from high-temperature blast furnace slag particles [J]. International Communications in Heat & Mass Transfer, 2015, 69: 23-28.
4	Baumann T , Zunft S . Development and performance assessment of a moving bed heat exchanger for solar central receiver power plants[C]//Solarpaces International Symposium on Concentrated Solar Power and Chemical Energy Technologies. 2014: 748-757.
5	Al-Ansary H , El-Leathy A , Al-Suhaibani Z , et al . Experimental study of a sand–air heat exchanger for use with a high-temperature solar gas turbine system[J]. Journal of Solar Energy Engineering, 2012, 134(4): 041017.
6	Chen J , Akiyama T , Nogami H , et al . Modeling of solid flow in moving beds[J]. Transactions of the Iron & Steel Institute of Japan, 1993, 33(6): 664-671.
7	Almendros-Ibáñez J A , Soria-Verdugo A , Ruiz-Rivas U , et al . Solid conduction effects and design criteria in moving bed heat exchangers[J]. Applied Thermal Engineering, 2011, 31(6): 1200-1207.
8	Bartsch P , Baumann T , Zunft S . Granular flow field in moving bed heat exchangers: a continuous model approach [J]. Energy Procedia, 2016, 99: 72-79.
9	陈中, 李庆领 . 横掠滴形管的局部及平均换热[J]. 武汉工程大学学报, 1997, 19(3): 1-4.
	Chen Z , Li Q L . Local and average heat transfer of cross drop-shaped tube[J]. Journal of Wuhan Institute of Chemical Technology, 1997, 19(3): 1-4.
10	刘安源, 刘石 . 流化床内颗粒碰撞传热的理论研究[J]. 中国电机工程学报, 2003, 23(3): 161-165.
	Liu A Y , Liu S . Theoretical study on impact heat transfer between particles in fluidized bed[J]. Proceedings of the CSEE, 2003, 23(3): 161-165.
11	武锦涛, 陈纪忠, 阳永荣 . 移动床中颗粒接触传热的数学模型[J]. 化工学报, 2006, 57(4): 719-725.
	Wu J T , Chen J Z , Yang Y R . Model of contact heat transfer in granular moving bed[J]. Journal of Chemical Industry and Engineering (China), 2006, 57(4): 719-725.
12	卜昌盛, 陈晓平, 刘道银, 等 . 基于颗粒尺度的离散颗粒传热模型[J]. 化工学报, 2012, 63(3): 698-704.
	Bu C S , Chen X P , Liu D Y , et al . Heat transfer model for particles with discrete element method[J]. CIESC Journal, 2012, 63(3): 698-704.
13	Vargas W L , Mccarthy J J . Heat conduction in granular materials[J]. MRS Proceedings, 2000, 627(5): 1052-1059.
14	Collier A P , Hayhurst A N , Richardson J L , et al . The heat transfer coefficient between a particle and a bed (packed or fluidised) of much larger particles[J]. Chemical Engineering Science, 2004, 59(21): 4613-4620.

[1]	Yiping FAN, Chunxi LU. Research progress on dedust scheme of coupling centrifugal force field with moving bed filtration [J]. CIESC Journal, 2023, 74(1): 157-169.
[2]	Peng WEI, Jun CHEN, Zhiguo WANG, Fei LIU. Improved productivity strategy of simulated moving bed based on binary-partial-discard [J]. CIESC Journal, 2022, 73(7): 3099-3108.
[3]	Tianqi TANG, Yurong HE. Effect of magnetic field on the mesoscale structure evolution process in a wet particle fluidized bed [J]. CIESC Journal, 2022, 73(6): 2636-2648.
[4]	Yilin LIU, Yu LI, Yaxiong YU, Zheqing HUANG, Qiang ZHOU. Construction of two parameter mesoscale heat transfer model for gas-solid flow based on resetting temperature method [J]. CIESC Journal, 2022, 73(6): 2612-2621.
[5]	Peng WEI, Jun CHEN, Zhiguo WANG, Fei LIU. Robust optimization of process parameters of simulated moving bed based on equilibrium theory [J]. CIESC Journal, 2022, 73(2): 792-800.
[6]	Xing TIAN, Jiayue ZHANG, Zhigang GUO, Jian YANG, Qiuwang WANG. Flow and heat transfer characteristics of particles flowing along the plate with different mixing elements [J]. CIESC Journal, 2022, 73(11): 4884-4892.
[7]	YAO Chuanyi, ZHENG Zhenwei, TU Zhixian, LU Yinghua. Separation of evodiamine and rutaecarpine with simulated moving bed chromatography [J]. CIESC Journal, 2021, 72(7): 3728-3737.
[8]	JIN Mo, LIU Daoyin, CHEN Xiaoping. Numerical simulation research of high-alkali coal ash deposition process based on discrete element method [J]. CIESC Journal, 2021, 72(4): 1939-1946.
[9]	Fang WANG, Xi ZENG, Tingting WANG, Xiaorong WANG, Rongcheng WU, Guangwen XU. Fundamentals and pilot demonstration of coal directional pyrolysis to high quality tar and gas products based on process intensification and reaction regulation [J]. CIESC Journal, 2021, 72(12): 6131-6143.
[10]	Jingxing YAO,Yao YANG,Zhengliang HUANG,Jingyuan SUN,Jingdai WANG,Yongrong YANG. Impact of viscosity model on simulation of condensed particle flow by Euler multiphase flow model [J]. CIESC Journal, 2020, 71(11): 4945-4956.
[11]	LI Bin, ZHANG Shangbin, ZHANG Lei, TENG Zhaoyu, WANG Youtian. Numerical simulation of bubble-particle flow in bubbling bed based on LBM-DEM [J]. CIESC Journal, 2018, 69(9): 3843-3850.
[12]	GAO Sihong, ZHANG Dandan, FAN Yiping, LU Chunxi. Pressure drop characteristics of dry gas purification process in a coupled apparatus of cyclone and granular bed filter/adsorber [J]. CIESC Journal, 2018, 69(5): 1873-1883.
[13]	QI Huabiao, XU Ji, SONG Wenli, GE Wei. Simulation on mixing granular materials in screw conveyor [J]. CIESC Journal, 2018, 69(1): 371-380.
[14]	LI Bin, YU Yang, MA Mengxiang, ZHANG Lei, CHEN Cuiling. Numerical simulation of mixing different sized wet and dry particles in three-dimensional spouted bed [J]. CIESC Journal, 2017, 68(12): 4545-4555.
[15]	WANG Qing, LI Jian, WANG Zhichao, ZHANG Lidong. Numerical simulation on characteristics of heat transfer between particles in rotary retorting [J]. CIESC Journal, 2017, 68(11): 4137-4146.