Experimental Research on Heat Transfer Characteristic of Liquid Lead-Bismuth Eutectic Flowing in Annular Channel

2018 ◽  
Author(s):  
Fengjie Zhu ◽  
Junmei Wu ◽  
Leitai Shi ◽  
G. H. Su
Keyword(s):  
Heat Transfer ◽  
Friction Coefficient ◽  
Flow Rate ◽  
Heat Transfer Characteristic ◽  
Convection Heat Transfer ◽  
Annular Channel ◽  
Transfer Characteristic ◽  
Liquid Lead ◽  
Convection Heat ◽  
Gas Lift

Liquid lead-bismuth eutectic (LBE) has been studied as a new type of coolant for an accelerator driven sub-critical system (ADS). And the gas-lift pump has been used to enhance the circulation capacity of coolant in ADS instead of mechanical pumps due to its simpler mechanical structure and higher security. The purpose of this experiment is to study the circulation capacity enhancement by gas-lift technique and the flow and heat transfer characteristic of liquid LBE in an annular channel. The experimental results show that: gas-injection can significantly increase liquid LBE mass flow rate, but the growth of liquid LBE mass flow rate will be reduced when gas flow rate reaches a value; The friction coefficient of liquid LBE in an annular channel decreases with the increase of Re and is larger than that calculated by Blasius formula at the same Re. For the convection heat transfer of liquid LBE in an annular channel, the heat conduction term is dominant, and Nusselt number increases with the increase of Peclet number. The experimental correlations of friction coefficient and convection heat transfer of liquid LBE in annular channel were fitted based on experimental data and compared with those from literature.

Numerical Investigation of a Symmetrical Combustion Burner and External Convection Heat Transfer Characteristics

2010 ◽  
Author(s):  
Xing Li ◽  
Li Jia ◽  
Hui Yang
Keyword(s):  
Heat Transfer ◽  
Water Flow ◽  
Heat Transfer Characteristic ◽  
Radiation Heat Transfer ◽  
Convection Heat Transfer ◽  
Transfer Characteristic ◽  
External Heat ◽  
Water Tank ◽  
Heat Transfer Characteristics ◽  
Radiation Heat

Combustion characteristic of natural gas (NG) in a symmetrical combustion chamber and external convection heat transfer characteristic of water flow has been investigated numerically. The burner using a combination of swirling premixed and jet diffusion flames to achieve high flame stability. The combined eddy dissipation model/finite rate chemistry (EDM/FRC) combustion models coupled with RNG k-ε turbulence model were applied to model turbulence combustion. The discrete transfer method (DTM) coupled with weighted sum of gray gas model (WSGGM) were applied to solve the radiation heat transfer. Accurate calculation results were obtained by coupling calculation of combustion in the combustion chamber and external water flow and heat transfer. The temperature fields, heat transfer characteristic in the combustor and water tank were obtained by numerical simulation. The effects of water inlet mass flow rate on combustion and external heat transfer characteristics were discussed. The results indicated that water flow has significant effect on external heat transfer. The temperature distribution is quite uniform in the water tank. Radiation heat transfer plays a dominant role of heat transfer in the combustor.

Forced Convection Heat Transfer for Helium Gas Under Exponentially Decreasing Flow Condition

2017 ◽  
Author(s):  
Qiusheng Liu ◽  
Li Wang ◽  
Makoto Shibahara ◽  
Katsuya Fukuda
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Forced Convection ◽  
Flow Rate ◽  
Convection Heat Transfer ◽  
Convection Heat ◽  
Rate Condition ◽  
Initial Flow ◽  
Helium Gas

Knowledge of the heat transfer phenomenon during flow decay transient condition is important for the safety assessment of very high temperature reactor (VHTR) during the loss of coolant accident. In this study, transient heat transfer from a horizontal cylinder to helium gas under exponentially decreasing flow rate condition was experimentally studied. The experiment was performed by using a forced convection heat transfer test loop. A flow control value with its control system was used to realize the flow decay condition. Helium gas was used as coolant and platinum cylinder with 1 mm in diameter was used as the test heater. A uniform heat generation rate was added to the cylinder by a power source. The cylinder temperature was maintained at an initial value under a definite initial flow rate of the helium gas. Then, the mass flow rate of the helium gas starts to decrease exponentially with different time constants ranged from 4.3 s to 15.4 s. The initial flow velocity ranged from 10 m/s to 4 m/s. The surface temperature, heat flux, and heat transfer coefficient were measured during the flow decay transient process under wide experimental conditions such as initial flow rate, flow decay time constant. It was found that the temperature of the test heater shows rapid increase during this process, the increasing rate of the temperature is higher for a shorter time constant. The heat transfer coefficient versus time during the flow rate decreasing process was also obtained. The transient heat transfer process during exponentially decreasing flow rate condition was clarified based on the experimental data.

Natural Convection Heat Transfer in a Vertical Square Duct With Radiation Effects

1999 ◽  
Author(s):  
Wei-Mon Yan ◽  
Kuan-Tzong Lee
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Flow Rate ◽  
Radiation Effects ◽  
Volume Flow Rate ◽  
Convection Heat Transfer ◽  
Volume Flow ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Square Duct

Abstract The present work investigates numerically the natural convection heat transfer with radiation effects in an open vertical square duct. The integro-differential radiative transfer equation is solved by discrete ordinates method. The vorticity-velocity formulation is applied to solve for the coupled momentum and energy equations. The effects of five major parameters, Grashof number Gr, conduction-to-radiation parameter Nc, optical thickness τ, single scattering albedo ω and temperature ratio Tr, on the combined natural and radiation heat transfer are discussed in detail. The numerical results of the dimensionless induced volume flow rate and average Nusselt numbers show that the thermal radiation would enhance the heat transfer rate. Additionally, the variations of the induced volume flow rate and total Nusselt number are independent of radiative parameters under fully-developed flow limit.

The Research of the Exergy Transfer Characteristic in the Process of Steady Heat Conduction during Constant-Section Straight Ribs

2013 ◽  
Vol 732-733 ◽  
pp. 176-181
Author(s):  
Bo Wei ◽  
Wei He ◽  
Xiao Chao Fan
Keyword(s):  
Heat Transfer ◽  
Convection Heat Transfer ◽  
Transfer Characteristic ◽  
Convection Heat ◽  
Temperature Parameter ◽  
Length Direction ◽  
Exergy Transfer ◽  
Steady Heat Conduction ◽  
Steady Heat ◽  
Constant Section

The ribs have been used to raise the area of convection heat transfer and consume little material simultaneously. This article adopt the analyze method of exergy transfer, with the help of gained temperature distribution in the constant-section straight ribs, derived the equation of the exergy distribution and the coefficient of exergy transfer distribution, with pay more attention to the rules of the energy quality decaying during the process of heat transfer in ribs. The solving results have been acquired in the Aluminium ribs and steel ribs with the case of same geometric parameter and same temperature parameter. The results show that the temperature, exergy value and the coefficient of exergy transfer is descending along the length direction of ribs. The parameter of Aluminium ribs is greater than the steel ribs because of the different property.

Two-Dimensional Free Convection Heat Transfer Below a Horizontal Hot Isothermal Flat Strip

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Milad Samie ◽  
Arash Nouri Gheimassi ◽  
Alinaghi Salari ◽  
Mohammad Behshad Shafii
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Flow Rate ◽  
Numerical Models ◽  
Convection Heat Transfer ◽  
Analytical Framework ◽  
Infinite Length ◽  
Convection Heat ◽  
Free Convection Heat ◽  
Flat Strip

Convection heat transfer below a horizontal, hot, and isothermal strip of infinite length and width of 2L embedded in fluids with different Prandtl number (Pr) and Nusselt number (Nu) is analyzed with the aid of integral method. A new concept is utilized to determine the boundary layer thickness at the strip's edge, which is based on matching the flow rate of the boundary layer below the strip at its edge and the flow rate of the plume, which forms after the heated fluid detaches from the strip's edge. In addition to these novelties, a numerical model is developed to verify the analytical framework, and an excellent agreement is observed between the analytical and numerical models.

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