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Jian Yang
MOE Key Laboratory of Thermo-Fluid Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China

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Journal article
Published: 14 April 2021 in Energies
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In this paper, the heat transfer of pin-fin plate unit (PFPU) under static and oscillating conditions are numerically studied using the discrete element method (DEM). The flow and heat transfer characteristics of the PFPU with sinusoidal oscillation are investigated under the conditions of oscillating frequency of 0–10 Hz, amplitude of 0–5 mm and oscillating direction of Y and Z. The contact number, contact time, porosity and heat transfer coefficient under the above conditions are analyzed and compared with the smooth plate. The results show that the particle far away from the plate can transfer heat with the pin-fin of PFPU, and the oscillating PFPU can significantly increase the contact number and enhance the temperature diffusion and heat transfer. The heat transfer coefficient of PFPU increases with the increase of oscillating frequency and amplitude. When the PFPU oscillates along the Y direction with the amplitude of 1 mm and the frequency of 10 Hz, the heat transfer coefficient of PFPU is increased by 28% compared with that of the smooth plate. Compared with the oscillation along the Z direction, the oscillation along the Y direction has a significant enhancement on the heat transfer of PFPU.

ACS Style

Xing Tian; Jian Yang; Zhigang Guo; Qiuwang Wang. Numerical Investigation of Gravity-Driven Granular Flow around the Vertical Plate: Effect of Pin-Fin and Oscillation on the Heat Transfer. Energies 2021, 14, 2187 .

AMA Style

Xing Tian, Jian Yang, Zhigang Guo, Qiuwang Wang. Numerical Investigation of Gravity-Driven Granular Flow around the Vertical Plate: Effect of Pin-Fin and Oscillation on the Heat Transfer. Energies. 2021; 14 (8):2187.

Chicago/Turabian Style

Xing Tian; Jian Yang; Zhigang Guo; Qiuwang Wang. 2021. "Numerical Investigation of Gravity-Driven Granular Flow around the Vertical Plate: Effect of Pin-Fin and Oscillation on the Heat Transfer." Energies 14, no. 8: 2187.

Journal article
Published: 17 March 2021 in Energies
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Membrane is the most important element of extrinsic Fabry-Perot interferometer sensors. Studying the relationship between working medium viscosity and membrane vibration characteristics are critical to the sensor design because the transformer oil viscosity will cause viscous loss during membrane vibration. The numerical investigation of membrane vibration characteristics in transformer oil is performed based on the finite element method. Besides, the effect of energy loss caused by viscosity is examined. It is firstly showed that the membrane has the highest sensitivity for the first-order vibration mode, and the transformer oil reduces the fundamental frequency by 60%. Subsequently, when viscosity and heat loss are considered, the amplitude is less than one-fifth of that without energy loss. The viscosity has a more significant effect on the velocity and temperature fields when the vibration frequency is close to the natural frequency. Finally, viscosity has a remarkable impact on the time domain response. Mechanical energy is converted into thermal energy during the vibration and the amplitude will gradually decrease with time. The effect of energy loss caused by viscosity on the membrane vibration characteristics is revealed, which would be important for an oil-immersed membrane design.

ACS Style

Wenrong Si; Weiqiang Yao; Hong Guan; Chenzhao Fu; Yiting Yu; Shiwei Su; Jian Yang. Numerical Study of Vibration Characteristics for Sensor Membrane in Transformer Oil. Energies 2021, 14, 1662 .

AMA Style

Wenrong Si, Weiqiang Yao, Hong Guan, Chenzhao Fu, Yiting Yu, Shiwei Su, Jian Yang. Numerical Study of Vibration Characteristics for Sensor Membrane in Transformer Oil. Energies. 2021; 14 (6):1662.

Chicago/Turabian Style

Wenrong Si; Weiqiang Yao; Hong Guan; Chenzhao Fu; Yiting Yu; Shiwei Su; Jian Yang. 2021. "Numerical Study of Vibration Characteristics for Sensor Membrane in Transformer Oil." Energies 14, no. 6: 1662.

Research article
Published: 28 September 2020 in Mathematical Problems in Engineering
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Transformer is one of the most important pieces of equipment in power system. The insulation aging and lifespan of transformer are significantly affected by hot spot distributions of internal components inside. In the present paper, the electromagnetic losses of different components and heat transfer process in a three-phase forced oil circulation transformer (400 kVA-15 kV/400 V) are numerically studied with finite element method. The leakage magnetic flux and eddy current loss density for metal components and oil tank are carefully analyzed, and the effect of metal components’ electromagnetic loss on hot spot temperature of different components and oil flow in transformer is also studied. It is found that the surface current of metal components is generated by leakage magnetic flux, and surface current density is large when leakage magnetic flux concentrates. The effect caused by relative magnetic permeability of metal components is remarkable on electromagnetic loss of metal components and oil tank, while the effect caused by relative magnetic permeability of transformer tank is relatively small. Due to the mixing of metal components on oil flow, the heat transfer of core is enhanced, its hot spot temperature is lowered, and the hot spot locations of coil and core also change. These results are meaningful for further understanding of heat transfer process in transformer and important for the optimal design of transformer.

ACS Style

Wen-Rong Si; Chen-Zhao Fu; Xu-Tao Wu; Xiu Zhou; Xiu-Guang Li; Yi-Ting Yu; Xiao-Yu Jia; Jian Yang; Hervé Laurent. Numerical Study of Electromagnetic Loss and Heat Transfer in an Oil-Immersed Transformer. Mathematical Problems in Engineering 2020, 2020, 1 -13.

AMA Style

Wen-Rong Si, Chen-Zhao Fu, Xu-Tao Wu, Xiu Zhou, Xiu-Guang Li, Yi-Ting Yu, Xiao-Yu Jia, Jian Yang, Hervé Laurent. Numerical Study of Electromagnetic Loss and Heat Transfer in an Oil-Immersed Transformer. Mathematical Problems in Engineering. 2020; 2020 ():1-13.

Chicago/Turabian Style

Wen-Rong Si; Chen-Zhao Fu; Xu-Tao Wu; Xiu Zhou; Xiu-Guang Li; Yi-Ting Yu; Xiao-Yu Jia; Jian Yang; Hervé Laurent. 2020. "Numerical Study of Electromagnetic Loss and Heat Transfer in an Oil-Immersed Transformer." Mathematical Problems in Engineering 2020, no. : 1-13.

Journal article
Published: 29 May 2020 in Journal of Heat Transfer
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Gradient particle size anode has shown great potential in improving the electrical performance of anode-supported solid oxide fuel cells (SOFCs). In this study, a 3D comprehensive model is established to study the effect of various gradient particle size distribution on the cell electrical performance for the anode microstructure optimization. The effect of homogeneous particle size on the cell performance is studied first. The maximum current density of homogeneous anode SOFC is obtained for the comparison with the electrical performance of gradient anode SOFC. Then the effect of various gradient particle size distribution on the cell molar fraction, polarization losses, and electronic current density distribution is analyzed and discussed in detail. Results show that increasing the particle diameter gradient can effectively reduce the anodic concentration overpotential. Decreasing the particle diameter of anode functional layer 2 is beneficial for reducing the activation and ohmic overpotentials. On these bases, the comprehensive electrical performance of SOFCs with gradient particle size anode and homogeneous anode is compared to highlight the optimal gradient particle diameter distribution. In the studied cases of this work, the gradient particle diameter of 0.7 μm, 0.4 μm, and 0.1 μm at anode support layer (ASL), anode functional layer 1, and anode functional layer 2 (case 3) is the optimal particle size distribution.

ACS Style

Pei Fu; Yuansheng Song; Jian Yang; Qiuwang Wang. Effect Analysis of Various Gradient Particle Size Distribution on Electrical Performance of Anode-Supported SOFCs With Gradient Anode. Journal of Heat Transfer 2020, 142, 1 .

AMA Style

Pei Fu, Yuansheng Song, Jian Yang, Qiuwang Wang. Effect Analysis of Various Gradient Particle Size Distribution on Electrical Performance of Anode-Supported SOFCs With Gradient Anode. Journal of Heat Transfer. 2020; 142 (7):1.

Chicago/Turabian Style

Pei Fu; Yuansheng Song; Jian Yang; Qiuwang Wang. 2020. "Effect Analysis of Various Gradient Particle Size Distribution on Electrical Performance of Anode-Supported SOFCs With Gradient Anode." Journal of Heat Transfer 142, no. 7: 1.

Journal article
Published: 16 April 2020 in Energies
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In the present paper, the heat transfer of gravity-driven dense particle flow around five different shapes of tubes is numerically studied using discrete element method (DEM). The velocity vector, particle contact number, particle contact time and heat transfer coefficient of particle flow at different particle zones around the tube are carefully analyzed. The results show that the effect of tube shape on the particle flow at both upstream and downstream regions of different tubes are remarkable. A particle stagnation zone and particle cavity zone are formed at the upstream and downstream regions of all the tubes. Both the stagnation and cavity zones for the circular tube are the largest, and they are the smallest for the elliptical tube. As the particle outlet velocity (vout) changes from 0.5 mm/s to 8 mm/s at dp = 1.72 mm/s, when compared with the circular tube, the heat transfer coefficient of particle flow for the elliptical tube and flat elliptical tube can increase by 20.3% and 15.0% on average, respectively. The proper design of the downstream shape of the tube can improve the overall heat transfer performance more efficiently. The heat transfer coefficient will increase as particle diameter decreases.

ACS Style

Xing Tian; Jian Yang; Zhigang Guo; Qiuwang Wang; Bengt Sunden. Numerical Study of Heat Transfer in Gravity-Driven Particle Flow around Tubes with Different Shapes. Energies 2020, 13, 1961 .

AMA Style

Xing Tian, Jian Yang, Zhigang Guo, Qiuwang Wang, Bengt Sunden. Numerical Study of Heat Transfer in Gravity-Driven Particle Flow around Tubes with Different Shapes. Energies. 2020; 13 (8):1961.

Chicago/Turabian Style

Xing Tian; Jian Yang; Zhigang Guo; Qiuwang Wang; Bengt Sunden. 2020. "Numerical Study of Heat Transfer in Gravity-Driven Particle Flow around Tubes with Different Shapes." Energies 13, no. 8: 1961.

Journal article
Published: 02 April 2020 in Powder Technology
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In the present paper, the heat transfer of gravity-driven dense particle flow around a hexagonal tube is numerically studied. The velocity vector, time-averaged particle contacting number, particle contacting time and heat transfer coefficient of particle flow are carfully analyzed. Furthermore, the heat transfer performances of particle flow around a hexagonal tube, circular tube and elliptical tube are also compared. The results show that, the effect of top angle (Θ) on the particle flow around a hexagonal tube is noticeable. When Θ decreases from 120° to 60° (vout = 2 mm/s), the averaged heat transfer coefficient of particle flow would increase by 29.7%. The heat transfer performances of particle flow around different shape tubes are quite different. When Θ equals 60° (vout = 2 mm/s), as compared with circular tube, the averaged heat transfer coefficient of particle flow around an elliptical tube and a hexagonal tube increases by 17.2% and 20.5%, respectively.

ACS Style

Xing Tian; Jian Yang; Zhigang Guo; Qiuwang Wang; Bengt Sunden. Numerical study of heat transfer in gravity-driven dense particle flow around a hexagonal tube. Powder Technology 2020, 367, 285 -295.

AMA Style

Xing Tian, Jian Yang, Zhigang Guo, Qiuwang Wang, Bengt Sunden. Numerical study of heat transfer in gravity-driven dense particle flow around a hexagonal tube. Powder Technology. 2020; 367 ():285-295.

Chicago/Turabian Style

Xing Tian; Jian Yang; Zhigang Guo; Qiuwang Wang; Bengt Sunden. 2020. "Numerical study of heat transfer in gravity-driven dense particle flow around a hexagonal tube." Powder Technology 367, no. : 285-295.

Journal article
Published: 06 December 2019 in Journal of Heat Transfer
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Microstructure modification of thick anode is an effective way to enhance cell performance of the anode-supported planar solid oxide fuel cells (SOFCs). In this work, the influence of multilayer anode microstructure with gradient porosity on cell mass transfer and electrical performance is numerically investigated. The coupled phenomena of fluid flow, multicomponent mass transfer, charge transport, and electrochemical reactions of SOFC, in three-dimensions (3D), are simulated by using the finite element computational fluid dynamics approach. Quantitative analyses of hydrogen concentration and anodic overpotentials are conducted to better understand the effect mechanism of the gradient porosity anode on the cell performance. The effect of gradient porosity distribution on the cell performance is also systematically discussed. It is found that the gradient porosity anode can significantly enhance the cell mass transfer performance to reduce the anodic concentration overpotential. The combined effects of activation, concentration, and ohmic overpotentials can effectively improve the cell electrical performance. For the cases studied, porosity gradient and porosity of anode functional layer 2 (AFL2) both range from 0.1 to 0.3. Results indicate that increasing the porosity gradient or porosity of AFL2 can enhance the cell mass transfer performance. As the porosity of AFL2 is higher than 0.2, the gradient porosity anode design is beneficial to improve the cell electrical performance.

ACS Style

Pei Fu; Jian Yang; Qiuwang Wang. Numerical Study on Mass Transfer and Electrical Performance of Anode-Supported Planar Solid Oxide Fuel Cells With Gradient Porosity Anode. Journal of Heat Transfer 2019, 142, 1 .

AMA Style

Pei Fu, Jian Yang, Qiuwang Wang. Numerical Study on Mass Transfer and Electrical Performance of Anode-Supported Planar Solid Oxide Fuel Cells With Gradient Porosity Anode. Journal of Heat Transfer. 2019; 142 (2):1.

Chicago/Turabian Style

Pei Fu; Jian Yang; Qiuwang Wang. 2019. "Numerical Study on Mass Transfer and Electrical Performance of Anode-Supported Planar Solid Oxide Fuel Cells With Gradient Porosity Anode." Journal of Heat Transfer 142, no. 2: 1.

Journal article
Published: 01 May 2019 in Energies
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In the present paper, the effective thermal conductivities of Li4SiO4-packed beds with both ordered and random packing structures were investigated using thermal resistance network methods based on both an Ohm’s law model and a Kirchhoff’s law model. The calculation results were also validated and compared with the numerical and experimental results. Firstly, it is proved that the thermal resistance network method based on the Kirchhoff’s law model proposed in the present study is reliable and accurate for prediction of effective thermal conductivities in a Li4SiO4-packed bed, while the results calculated with the Ohm’s law model underestimate both ordered and random packings. Therefore, when establishing a thermal resistance network, the thermal resistances should be connected along the main heat transfer direction and other heat transfer directions as well in the packing unit. Otherwise, both the total heat flux and effective thermal conductivity in the packing unit will be underestimated. Secondly, it is found that the effect of the packing factor is remarkable. The effective thermal conductivity of a packed bed would increase as the packing factor increases. Compared with random packing at similar packing factor, the effective thermal conductivity of packed bed would be further improved with an ordered packing method.

ACS Style

Jian Yang; Yingxue Hu; Qiuwang Wang. Investigation of Effective Thermal Conductivity for Ordered and Randomly Packed Bed with Thermal Resistance Network Method. Energies 2019, 12, 1666 .

AMA Style

Jian Yang, Yingxue Hu, Qiuwang Wang. Investigation of Effective Thermal Conductivity for Ordered and Randomly Packed Bed with Thermal Resistance Network Method. Energies. 2019; 12 (9):1666.

Chicago/Turabian Style

Jian Yang; Yingxue Hu; Qiuwang Wang. 2019. "Investigation of Effective Thermal Conductivity for Ordered and Randomly Packed Bed with Thermal Resistance Network Method." Energies 12, no. 9: 1666.

Research article
Published: 25 February 2019 in Mathematical Problems in Engineering
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Trefoil buried cable is one of the important cable arrangements for the underground transmission line, and its heat transfer performance is relatively poor. By filling with fluidized thermal backfill material (FTB) around trefoil buried cables, the heat transfer would be efficiently enhanced, while the filling cost should also be considered. In the present study, the heat transfer process in the FTB trefoil buried cables is numerically studied, where the cable core loss and eddy current loss in the cable were coupled for the simulation. The heat transfer performances and ampacities for trefoil buried cables with different back fill materials were analysed and compared with each other. Then, the laying parameters for the parabolic-type FTB trefoil buried cables were optimized with the radial basis function neural network (RBNN) and genetic algorithm (GA). Firstly, it is found that, with FTB material, the maximum temperature in the cable core is obviously reduced, and the cable ampacity is greatly improved as compared with the cables buried around natural soil (NS). Secondly, when compared with flat-type FTB model, the heat transfer rate in the cable with parabolic-type FTB laying method would be slightly reduced, while the FTB amount used for the buried cables is greatly reduced. Finally, as for parabolic-type FTB trefoil buried cables, with proper design of geometric parameters (s1 = 0.290 m, s2 = 0.302 m, and l = 0.3 m with I = 1300 A) for the FTB laying cross section, the overall performance for the cable was optimized.

ACS Style

Chen-Zhao Fu; Wen-Rong Si; Lei Quan; Jian Yang. Numerical Study of Heat Transfer in Trefoil Buried Cable with Fluidized Thermal Backfill and Laying Parameter Optimization. Mathematical Problems in Engineering 2019, 2019, 1 -13.

AMA Style

Chen-Zhao Fu, Wen-Rong Si, Lei Quan, Jian Yang. Numerical Study of Heat Transfer in Trefoil Buried Cable with Fluidized Thermal Backfill and Laying Parameter Optimization. Mathematical Problems in Engineering. 2019; 2019 ():1-13.

Chicago/Turabian Style

Chen-Zhao Fu; Wen-Rong Si; Lei Quan; Jian Yang. 2019. "Numerical Study of Heat Transfer in Trefoil Buried Cable with Fluidized Thermal Backfill and Laying Parameter Optimization." Mathematical Problems in Engineering 2019, no. : 1-13.

Journal article
Published: 01 February 2019 in International Journal of Heat and Mass Transfer
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ACS Style

Yingxue Hu; Jingyu Wang; Jian Yang; Issam Mudawar; Qiuwang Wang. . International Journal of Heat and Mass Transfer 2019, 1 .

AMA Style

Yingxue Hu, Jingyu Wang, Jian Yang, Issam Mudawar, Qiuwang Wang. . International Journal of Heat and Mass Transfer. 2019; ():1.

Chicago/Turabian Style

Yingxue Hu; Jingyu Wang; Jian Yang; Issam Mudawar; Qiuwang Wang. 2019. "." International Journal of Heat and Mass Transfer , no. : 1.

Journal article
Published: 01 February 2019 in Energy Procedia
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Underground power cable system has been wildly used as an effective transmission line. This paper presents the thermal analysis of the two formations (Flat and Trefoil) of buried system. Temperature-dependent thermal conductivity of soil was considered in the research and the Fluidized Thermal Backfill (FTB) was applied to increase the ability of heat dissipation of power cable system. Further, the influences of heat transfer performance and ampacity on power cable systems were studied when FTB was applied in two formations. Firstly, it is found that the geometric parameters have significantly effects on the heat transfer performance of underground power cable system. Secondly, considering the temperature-dependent thermal conductivity, the maximum temperature of cables will rise rapidly, the limited temperature is easy to reach. The application of FTB can enhance the heat transfer of the whole system, especially for trefoil formation. Finally, the analysis of ampacity shows that the FTB will ensure the higher loading current in a security condition with the temperature-dependent thermal conductivity.

ACS Style

Lei Quan; Chenzhao Fu; Wenrong Si; Jian Yang; Qiuwang Wang. Numerical study of heat transfer in underground power cable system. Energy Procedia 2019, 158, 5317 -5322.

AMA Style

Lei Quan, Chenzhao Fu, Wenrong Si, Jian Yang, Qiuwang Wang. Numerical study of heat transfer in underground power cable system. Energy Procedia. 2019; 158 ():5317-5322.

Chicago/Turabian Style

Lei Quan; Chenzhao Fu; Wenrong Si; Jian Yang; Qiuwang Wang. 2019. "Numerical study of heat transfer in underground power cable system." Energy Procedia 158, no. : 5317-5322.

Articles
Published: 19 January 2019 in Heat Transfer Engineering
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In the present paper, the forced convective heat transfer was experimentally studied in packed beds with uniform and non-uniform spheres. The pore structures of different packings were reconstructed with discrete element method, and the lateral porosity distributions were analyzed. Furthermore, the pressure drop, heat transfer and overall heat transfer performances of different packings were investigated and compared with each other. Firstly, it is found that, using laterally layered composite packing (LLM), smaller pores would be formed close to the tube wall and big flow channels would be formed in the inner-tube region, which would reduce the tube-wall effect in the near tube wall region of packed bed. When compared with mono-sized packing with lower tube to particle diameter ratio, both the heat transfer and overall heat transfer capacities would be improved with LLM packing method. Secondly, it is found that, using randomly composite packing (RCM) or axially layered composite packing (ALM), both the lateral porosity magnitude and amplitude of packed bed are lower than those of mono-sized packing with higher tube to particle diameter ratio in the near tube-wall region. The tube-wall effect would be further reduced, and both the heat transfer and overall heat transfer capacities would also be improved with RCM and ALM packing methods.

ACS Style

Jian Yang; Yingxue Hu; Pei Qian; Zhigang Guo; Qiuwang Wang. Experimental Study of Forced Convective Heat Transfer in Packed Beds With Uniform and Non-Uniform Spheres. Heat Transfer Engineering 2019, 41, 351 -360.

AMA Style

Jian Yang, Yingxue Hu, Pei Qian, Zhigang Guo, Qiuwang Wang. Experimental Study of Forced Convective Heat Transfer in Packed Beds With Uniform and Non-Uniform Spheres. Heat Transfer Engineering. 2019; 41 (4):351-360.

Chicago/Turabian Style

Jian Yang; Yingxue Hu; Pei Qian; Zhigang Guo; Qiuwang Wang. 2019. "Experimental Study of Forced Convective Heat Transfer in Packed Beds With Uniform and Non-Uniform Spheres." Heat Transfer Engineering 41, no. 4: 351-360.

Research article
Published: 17 September 2018 in Mathematical Problems in Engineering
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Pipe cable is considered as an important form for underground transmission line. The maximum electrical current (ampacity) of power cable system mostly depends on the cable conductor temperature. Therefore, accurate calculation of temperature distribution in the power cable system is quite important to extract the cable ampacity. In the present paper, the fluid flow and heat transfer characteristics in the pipe cable with alternating current were numerically studied by using commercial code COMSOL MULTIPHYSICS based on finite element method (FEM). The cable core loss and eddy current loss in the cable were coupled for the heat transfer simulation, and the difference of heat transfer performances with pure natural convection model and radiation-convection model was compared and analysed in detail. Meanwhile, for the radiation-convection model, the effects caused by radiant emissivity of cable surface and pipe inner surface, as well as the cable location in the pipe, were also discussed. Firstly, it is revealed that the radiation and natural convection heat flux on the cable surface would be of the same order of magnitude, and the radiation heat transfer on the cable surface should not be ignored. Otherwise, the cable ampacity would be underestimated. Secondly, it is found that the overall heat transfer rate on the cable surface increases as the cable surface emissivity increases, and this is more remarkable to the upper cable. While the effect caused by the radiant emissivity on the pipe inner surface would be relatively small. Furthermore, it is demonstrated that, as cable location in the pipe falls, the natural convection heat transfer would be enhanced. These results would be meaningful for the ampacity prediction and optimum design for the pipe cable.

ACS Style

Chen-Zhao Fu; Wen-Rong Si; Lei Quan; Jian Yang. Numerical Study of Convection and Radiation Heat Transfer in Pipe Cable. Mathematical Problems in Engineering 2018, 2018, 1 -12.

AMA Style

Chen-Zhao Fu, Wen-Rong Si, Lei Quan, Jian Yang. Numerical Study of Convection and Radiation Heat Transfer in Pipe Cable. Mathematical Problems in Engineering. 2018; 2018 ():1-12.

Chicago/Turabian Style

Chen-Zhao Fu; Wen-Rong Si; Lei Quan; Jian Yang. 2018. "Numerical Study of Convection and Radiation Heat Transfer in Pipe Cable." Mathematical Problems in Engineering 2018, no. : 1-12.

Journal article
Published: 01 July 2018 in Energy
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In the present paper, grille-sphere composite pebble bed (GSCPB) is developed to improve the hydrodynamic and heat transfer performances for high temperature gas cooled reactor with 10MW (HTR-10). The fluid flow and heat transfer characteristics in typical GSCPB channels are numerically investigated, and the effects of typical parameters on the pressure drop and maximum pebble temperature inside are carefully analyzed with Taguchi method. Firstly, in the GSCPB bed, the grille can not only support the pebbles to achieve a structured packing quickly, but can also enhance convective heat transfer from pebbles to the fluid. With proper design of grille inside, the heat transfer rate would be improved and the pressure drop would be reduced in GSCPB channel when compared with traditional random pebble bed. Secondly, the effect of sub-channel width to pebble diameter ratio (N) on both the hydrodynamic and heat transfer performances in GSCPB channel is quite significant. The contribution ratios of N on the pressure drop and maximum pebble temperature in GSCPB channel are of 86.3% and 81.0%, respectively. Finally, with Taguchi method, the optimum design parameter combinations are obtained for the lowest pressure drop and lowest maximum pebble temperature in GSCPB channels, respectively.

ACS Style

Yingxue Hu; Jian Yang; Jingyu Wang; Qiuwang Wang. Investigation of hydrodynamic and heat transfer performances in grille-sphere composite pebble beds with DEM-CFD-Taguchi method. Energy 2018, 155, 909 -920.

AMA Style

Yingxue Hu, Jian Yang, Jingyu Wang, Qiuwang Wang. Investigation of hydrodynamic and heat transfer performances in grille-sphere composite pebble beds with DEM-CFD-Taguchi method. Energy. 2018; 155 ():909-920.

Chicago/Turabian Style

Yingxue Hu; Jian Yang; Jingyu Wang; Qiuwang Wang. 2018. "Investigation of hydrodynamic and heat transfer performances in grille-sphere composite pebble beds with DEM-CFD-Taguchi method." Energy 155, no. : 909-920.

Journal article
Published: 15 April 2018 in Energies
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Packed beds are widely used in catalytic reactors or nuclear reactors. Reducing the pressure drop and improving the heat transfer performance of a packed bed is a common research aim. The dimpled structure has a complex influence on the flow and heat transfer characteristics. In the present study, the flow and heat transfer characteristics in structured packed beds with smooth or dimpled spheres are numerically investigated, where two different low channel to particle diameter ratios (N = 1.00 and N = 1.15) are considered. The pressure drop and the Nusselt number are obtained. The results show that, for N = 1.00, compared with the structured packed bed with smooth spheres, the structured packed bed with dimpled spheres has a lower pressure drop and little higher Nusselt number at 1500 < ReH < 14,000, exhibiting an improved overall heat transfer performance. However, for N = 1.15, the structured packed bed with dimpled spheres shows a much higher pressure drop, which dominantly affects the overall heat transfer performance, causing it to be weaker. Comparing the different channel to particle diameter ratios, we find that different configurations can result in: (i) completely different drag reduction effect; and (ii) relatively less influence on heat transfer enhancement.

ACS Style

Shiyang Li; Lang Zhou; Jian Yang; Qiuwang Wang. Numerical Simulation of Flow and Heat Transfer in Structured Packed Beds with Smooth or Dimpled Spheres at Low Channel to Particle Diameter Ratio. Energies 2018, 11, 937 .

AMA Style

Shiyang Li, Lang Zhou, Jian Yang, Qiuwang Wang. Numerical Simulation of Flow and Heat Transfer in Structured Packed Beds with Smooth or Dimpled Spheres at Low Channel to Particle Diameter Ratio. Energies. 2018; 11 (4):937.

Chicago/Turabian Style

Shiyang Li; Lang Zhou; Jian Yang; Qiuwang Wang. 2018. "Numerical Simulation of Flow and Heat Transfer in Structured Packed Beds with Smooth or Dimpled Spheres at Low Channel to Particle Diameter Ratio." Energies 11, no. 4: 937.

Original articles
Published: 21 September 2017 in Heat Transfer Engineering
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In this paper, the flow and heat transfer performances inside small pores of structured packed beds of dimple particles are numerically investigated for the first time and some interesting transport phenomena are obtained. Three-dimensional Navier–Stokes equations and SST k-ω turbulence model are adopted for the simulations. The effect of dimple depth is studied in detail, and the flow and heat transfer performances in the packed beds with dimple particles and smooth particles are also compared with each other. It is found that, with the same inlet velocity, the pressure drop and heat transfer in the packed bed with dimple particles would be lower than those in the packed bed with smooth particles, while the overall heat transfer efficiency of packed bed with dimple particles is higher. Furthermore, for the packed bed of dimple particles, the effect of dimple depth is remarkable. With the same inlet velocity, both the pressure drop and heat transfer rate of the packed bed decrease as dimple depth increases, while the overall heat transfer rate is similar for the packed bed with different dimple depths.

ACS Style

Jian Yang; Lang Zhou; Yingxue Hu; Shiyang Li; Qiuwang Wang. Numerical Study of Forced Convective Heat Transfer in Structured Packed Beds of Dimple-Particles. Heat Transfer Engineering 2017, 39, 1582 -1592.

AMA Style

Jian Yang, Lang Zhou, Yingxue Hu, Shiyang Li, Qiuwang Wang. Numerical Study of Forced Convective Heat Transfer in Structured Packed Beds of Dimple-Particles. Heat Transfer Engineering. 2017; 39 (17-18):1582-1592.

Chicago/Turabian Style

Jian Yang; Lang Zhou; Yingxue Hu; Shiyang Li; Qiuwang Wang. 2017. "Numerical Study of Forced Convective Heat Transfer in Structured Packed Beds of Dimple-Particles." Heat Transfer Engineering 39, no. 17-18: 1582-1592.

Journal article
Published: 22 April 2016 in International Journal of Heat and Mass Transfer
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Fluid flow and heat transfer in a randomly packed bed of sinter particles (RPBSP) is experimentally investigated. Based on the Chilton–Colburn analogy, heat transfer performance is obtained by the naphthalene sublimation technique. The sinter particles, which are coated with naphthalene, are sublimated to obtain the mass transfer characteristics. The results of pressure drop (Δp) in the RPBSP show that most experimental values are within the ±20% deviations of the modified Ergun’s equation. The results of Nusselt number (Nu) indicate that, the heat transfer characteristics of the randomly packed bed of the irregular particles are different from that of regular surface particles. Slopes of heat transfer correlations of the RPBSP are larger than these with spheres. Based on the experimental investigations, we employ genetic algorithm (GA) to derive heat transfer correlations. It is found that the GA approach can correlate Nu quite well and two new correlations are obtained to describe convective heat transfer in the RPBSP. Comparisons between correlations developed in the present work and other correlations are also conducted. Lastly, effects of sphericity and porosity are included in a heat transfer correlation when considering physics and heat transfer characteristics. The investigation provides thoughts for dealing with the packed beds with irregular particles, as well as the newly obtained correlations for construction of the mathematical model in sinter cooling bed and design of new cooling equipment.

ACS Style

Yan Liu; Jingyu Wang; Zhilong Cheng; Jian Yang; Qiuwang Wang. Experimental investigation of fluid flow and heat transfer in a randomly packed bed of sinter particles. International Journal of Heat and Mass Transfer 2016, 99, 589 -598.

AMA Style

Yan Liu, Jingyu Wang, Zhilong Cheng, Jian Yang, Qiuwang Wang. Experimental investigation of fluid flow and heat transfer in a randomly packed bed of sinter particles. International Journal of Heat and Mass Transfer. 2016; 99 ():589-598.

Chicago/Turabian Style

Yan Liu; Jingyu Wang; Zhilong Cheng; Jian Yang; Qiuwang Wang. 2016. "Experimental investigation of fluid flow and heat transfer in a randomly packed bed of sinter particles." International Journal of Heat and Mass Transfer 99, no. : 589-598.

Journal article
Published: 01 April 2016 in Nuclear Engineering and Design
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The effect of the tube wall on the fluid flow and heat transfer would be important in the packed bed with low tube to particle diameter ratio, which may lead to flow and temperature maldistributions inside, and the heat transfer performance may be lowered. In the present paper, the flow and heat transfer performances in both the composite and uniform packed beds of spheres with low tube to particle diameter were numerically investigated, where the composite packing means randomly packing with non-uniform spheres and the uniform packing means randomly packing with uniform spheres, including radially layered composite packing (RLM), axially layered composite packing (ALM), randomly composite packing (RCM) and randomly uniform packing (RPM). Both the composite and uniform packings were generated with discrete element method (DEM), and the influence of the wall effect on the flow and heat transfer in the packed beds were carefully studied and compared with each other. Firstly, it is found that, the wall effect on the velocity and temperature distributions in the randomly packed bed of uniform spheres (RPM) with low tube to particle diameter ratio were obvious. The average velocity of the near-tube-wall region is higher than that of the inner-tube region in the bed. When the tube wall is adiabatic, the average temperature of the near-tube-wall region is lower. With radially layered composite packing method (RLM), smaller pores would be formed close to the tube wall and big flow channels would be formed in the inner-tube region of the bed, which would be benefit to restrain the wall effect and improve heat transfer in the bed with low tube to particle diameter ratio. Furthermore, it is also found that, with composite packing method (RLM, ALM and RCM), both the pressure drop and heat flux are higher than those in the uniform packing (RPM). And with radially layered packing method (RLM), the flow resistance would be reduced, and both the heat flux and overall heat transfer efficiency would be further improved for the composite packing with low tube to particle diameter ratio.

ACS Style

Jian Yang; Jiangquan Wu; Lang Zhou; Qiuwang Wang. Computational study of fluid flow and heat transfer in composite packed beds of spheres with low tube to particle diameter ratio. Nuclear Engineering and Design 2016, 300, 85 -96.

AMA Style

Jian Yang, Jiangquan Wu, Lang Zhou, Qiuwang Wang. Computational study of fluid flow and heat transfer in composite packed beds of spheres with low tube to particle diameter ratio. Nuclear Engineering and Design. 2016; 300 ():85-96.

Chicago/Turabian Style

Jian Yang; Jiangquan Wu; Lang Zhou; Qiuwang Wang. 2016. "Computational study of fluid flow and heat transfer in composite packed beds of spheres with low tube to particle diameter ratio." Nuclear Engineering and Design 300, no. : 85-96.

Journal article
Published: 01 June 2015 in Journal of Heat Transfer
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In the present paper, the genetic programing (GP) is integrated with the genetic algorithm (GA) for deriving heat transfer correlations. In the process of developing heat transfer correlations with the approach (GP with GA (GPA)), the GP is first employed to obtain some potential optimal forms. After that, the forms are further optimized with the global GA to reach minimum errors between the predicted values and experimental values. With the proposed approach, three typical different heat transfer problems are applied to the data reduction processes from published experimental data, which are heat transfer in a shell-and-tube heat exchanger (STHE) with continuous helical baffles, a single row heat exchanger with helically finned tubes and a finned oval-tube heat exchanger with double rows of tubes, respectively. The results indicate that the GPA approach could improve the performance of heat transfer correlations obtained with the GP. Compared with the power-law-based correlations, the heat transfer correlations obtained with the approach have higher predicted accuracies and more excellent robustness.

ACS Style

Yan Liu; Jian Yang; Jing Xu; Zhilong Cheng; Qiu-Wang Wang. Integration of Genetic Programing With Genetic Algorithm for Correlating Heat Transfer Problems. Journal of Heat Transfer 2015, 137, 061012 .

AMA Style

Yan Liu, Jian Yang, Jing Xu, Zhilong Cheng, Qiu-Wang Wang. Integration of Genetic Programing With Genetic Algorithm for Correlating Heat Transfer Problems. Journal of Heat Transfer. 2015; 137 (6):061012.

Chicago/Turabian Style

Yan Liu; Jian Yang; Jing Xu; Zhilong Cheng; Qiu-Wang Wang. 2015. "Integration of Genetic Programing With Genetic Algorithm for Correlating Heat Transfer Problems." Journal of Heat Transfer 137, no. 6: 061012.

Journal article
Published: 30 March 2015 in Experimental Thermal and Fluid Science
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In the present study, the electrochemical technique is used to test flow transitions in random packed beds with five low tube to particle diameter ratios (N = dt/dp), including N = 2.6, 5.3, 8.1, 9.9 and 12.5. The microelectrodes are placed at the tube wall and inner particle surfaces to test the local flow at the pore level, with particle Reynolds number (Re) ranging from 20 to 2200. The critical Reynolds numbers corresponding to the end of laminar flow and onset of turbulent flow are obtained according to Fluctuating Rate (FR) of current signals. The results of tube wall probes and inner probes are compared in detail to analyze the influences of the tube to particle diameter ratio N on flow transitions. It is found that, the critical Reynolds numbers corresponding to the end of laminar flow regime of packed beds with different tube to particle diameter ratios are at about 110 for packed beds with N = 5.3, 8.1, 9.9 and 12.5. Meanwhile, as the tube to particle diameter ratio N increases, the onset of turbulence would take place earlier for inner probes in different packed beds. Furthermore, the critical Reynolds numbers corresponding to both the end of laminar flow and onset of turbulent flow in the packed bed with N = 9.9 are quite close to those in the packed bed with N = 12.5, which would indicate that, when N ⩾ 9.9, the wall effects on flow transitions in the packed beds would be unremarkable.

ACS Style

Jian Yang; Shanshan Bu; Qingtai Dong; Jiangquan Wu; Qiuwang Wang. Experimental study of flow transitions in random packed beds with low tube to particle diameter ratios. Experimental Thermal and Fluid Science 2015, 66, 117 -126.

AMA Style

Jian Yang, Shanshan Bu, Qingtai Dong, Jiangquan Wu, Qiuwang Wang. Experimental study of flow transitions in random packed beds with low tube to particle diameter ratios. Experimental Thermal and Fluid Science. 2015; 66 ():117-126.

Chicago/Turabian Style

Jian Yang; Shanshan Bu; Qingtai Dong; Jiangquan Wu; Qiuwang Wang. 2015. "Experimental study of flow transitions in random packed beds with low tube to particle diameter ratios." Experimental Thermal and Fluid Science 66, no. : 117-126.