scholarly journals Thermal Hydraulics Analysis of the Distribution Zone in Small Modular Dual Fluid Reactor

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1065
Author(s):  
Chunyu Liu ◽  
Xiaodong Li ◽  
Run Luo ◽  
Rafael Macian-Juan
Keyword(s):  
Heat Transfer ◽  
Molten Salt ◽  
Heat Removal ◽  
Core Region ◽  
Major Influence ◽  
Liquid Lead ◽  
Thermal Hydraulics ◽  
The Core ◽  
Removal Capacity ◽  
Power Peak

The Small Modular Dual Fluid Reactor (SMDFR) is a novel molten salt reactor based on the dual fluid reactor concept, which employs molten salt as fuel and liquid lead/lead-bismuth eutectic (LBE) as coolant. A unique design of this reactor is the distribution zone, which locates under the core and joins the core region with the inlet pipes of molten salt and coolant. Since the distribution zone has a major influence on the heat removal capacity in the core region, the thermal hydraulics characteristics of the distribution zone have to be investigated. This paper focuses on the thermal hydraulics analysis of the distribution zone, which is conducted by the numerical simulation using COMSOL Multiphysics with the CFD (Computational Fluid Dynamics) module and the Heat Transfer module. The energy loss and heat exchange in the distribution zone are also quantitatively analyzed. The velocity and temperature distributions of both molten salt and coolant at the outlet of the distribution zone, as inlet of the core region, are produced. It can be observed that the outlet velocity profiles are proportional in magnitude to the inlet velocity ones with a similar shape. In addition, the results show that the heat transfer in the center region is enhanced due to the velocity distribution, which could compensate the power peak and flatten the temperature distribution for a higher power density.

Feasibility Investigation of the Decay Heat Removal Capability Using the Concept of a Thermosyphon in the Liquid Metal Reactor

2002 ◽  
Author(s):  
Yeon-Sik Kim ◽  
Yoon-Sub Sim ◽  
Eui-Kwang Kim
Keyword(s):  
Heat Transfer ◽  
Liquid Metal ◽  
Heat Removal ◽  
Term Operation ◽  
Decay Heat ◽  
Removal Capacity ◽  
Liquid Metal Reactor ◽  
Current Design ◽  
Heat Removal System ◽  
Removal System

A new design concept for a decay heat removal system in a liquid metal reactor is proposed. The new design utilizes a thermosyphon to enhance the heat removal capacity and its heat transfer characteristics are analyzed against the current PSDRS (Passive Safety Decay heat Removal System) in the KALIMER (Korea Advanced LIquid MEtal Reactor) design. The preliminary analysis results show that the new design with a thermosyphon yields substantial increase of 20∼40% in the decay heat removal capacity compared to the current design that do not have the thermosyphon. The new design reduces the temperature rise in the cooling air of the system and helps the surrounding structure in maintaining its mechanical integrity for long term operation at an accident. Also the analysis revealed the characteristics of the interactions among various heat transfer modes in the new design.

A Study of Convective Heat Transfer in a Model Rotor–Stator Disk Cavity

2001 ◽  
Vol 123 (3) ◽  
pp. 621-632 ◽  
Author(s):  
R. P. Roy ◽  
G. Xu ◽  
J. Feng
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Air Flow ◽  
Disk Surface ◽  
Core Region ◽  
Air Flow Rate ◽  
The Core ◽  
Rotor Disk ◽  
Secondary Air

In this study, the fluid (air) temperature field and the convective heat flux distribution on the rotor disk surface were measured and computed in a model rotor–stator disk cavity. Both mainstream flow and secondary air flow were provided. The radial distribution of convective heat transfer coefficient on the rotor disk surface, which was calculated as the ratio of the local heat flux and the local temperature difference across the thermal boundary layer on the disk, is also reported. In the experiments, the disk rotational Reynolds number, Reϕ, ranged from 4.65×105 to 8.6×105, and the nondimensional secondary air flow rate, cw, ranged from 1504 to 7520. The secondary air was supplied at the cavity hub. All experiments were carried out at the same mainstream air flow rate, Rem=5.0×105. The cavity fluid temperature distribution was measured by traversing miniature thermocouples, and the rotor disk surface temperature and heat flux were measured by a quasi-steady thermochromic liquid crystal technique in conjunction with resistance temperature detectors embedded in the disk. The measurements are compared with predictions from the commercial CFD code Fluent. The Fluent simulations were performed in the rotationally symmetric mode using a two-zone description of the flow field and the RNG k-ε model of turbulence. The convective heat transfer coefficient distribution on the rotor disk surface exhibited the influence of the source region and the core region of air flow in the cavity. In the source region, which is radially inboard, the convective heat transfer was dominated by the secondary air flow rate. In the core region, which is radially outboard, the heat transfer was dominated by the rotational motion of the fluid relative to the rotor disk. An empirical correlation for the local Nusselt number on the rotor disk surface is suggested for the core region.

Steady Thermal Hydraulics Analysis for a Graphite-Moderated Channel Type Molten Salt Reactor

2008 ◽  
Author(s):  
Dalin Zhang ◽  
Suizheng Qiu
Keyword(s):  
Molten Salt ◽  
Flow Distribution ◽  
Axial Direction ◽  
Theoretical Models ◽  
Outer Wall ◽  
Molten Salt Reactor ◽  
Thermal Hydraulics ◽  
The Core ◽  
Fuel Salt ◽  
Channel Type

The Molten Salt Reactor (MSR) is one of the six GENIV systems capable of breading and burning. In this paper, a graphite-moderated channel type MSR was selected for conceptual research. For this MSR, a ternary system of 0.15LiF-0.58NaF-0.27BeF2 was proposed as the reactor fuel solvent, coolant and also moderator simultaneously with ca.1 mol% UF4 dissolving in it, which circulates through the whole primary loop accompanying fission reaction only in the core. 169 hexagonal graphite elements, each with a central fuel channel, are arranged in the core symmetrically by 30° angles. The theoretical models of the thermal hydraulics under steady condition are conducted in one-twelfth of the core and calculated by the numerical method. The DRAGON code is adopted to calculate the axial and radial power factors. The flow and heat transfer models in the fuel salt and graphite are founded basing on the fundamental mass, momentum and energy equations. The calculated results show the detailed mass flow distribution in the core; and the temperature of the fuel salt, inner and outer wall in the calculated elements along the axial direction are also obtained.

Experimental Investigation of Natural Convection in Partitioned Enclosures

1982 ◽  
Vol 104 (3) ◽  
pp. 527-532 ◽  
Author(s):  
S. M. Bajorek ◽  
J. R. Lloyd
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Convection Heat Transfer ◽  
Core Region ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
The Core ◽  
Different Temperatures ◽  
Vertical Walls ◽  
Good Agreement

Natural convection heat transfer within a two-dimensional, partitioned enclosure of aspect ratio 1 was investigated experimentally using a Mach-Zehnder interferometer. The vertical walls were maintained isothermal at different temperatures, while the horizontal walls and the partitions were insulated. Local and average heat-transfer coefficients were determined for the air and carbon dioxide filled enclosures both with and without partitions for Grashof numbers between 1.7×105 and 3.0×106. Good agreement was found between the results in the present study for the nonpartitioned enclosure and those previously published. The partitions were found to significantly influence the convective heat transfer. Observations of the interferometric fringes indicated that the core region is unsteady, with the unsteadiness occasionally affecting the flow along the vertical isothermal walls, beginning at Grashof numbers as low as 5×105.

Numerical Research on Steady Coupling of Neutronics and Thermal-Hydraulics for a Molten Salt Reactor

2008 ◽  
Author(s):  
Dalin Zhang ◽  
Changliang Liu ◽  
Libo Qian ◽  
Guanghui Su ◽  
Suizheng Qiu
Keyword(s):  
Thermal Neutron ◽  
Molten Salt ◽  
Molten Salt Reactor ◽  
Thermal Hydraulics ◽  
Steady Condition ◽  
Delayed Neutron ◽  
The Core ◽  
Production Of Hydrogen ◽  
Fuel Salt ◽  
Salt Flow

The Molten Salt Reactor (MSR), which is one of the ‘Generation IV’ concepts, can be used for production of electricity, actinide burning, production of hydrogen, and production of fissile fuels. In this paper, a single-liquid-fueled MSR was selected for conceptual research. For this MSR, a ternary system of 15%LiF-58%NaF-27%BeF2 was proposed as the reactor fuel solvent, coolant and also moderator with ca. 1 mol% UF4 dissolving in it, which circulates through the whole primary loop accompanying fission reaction only in the core. The fuel salt flow makes the MSR different from the conventional reactors using solid fissile materials, and makes the neutronics and thermal-hydraulic coupled strongly, which plays the important role in the research of reactor safety analysis. Therefore, it’s necessary to study the coupling of neutronics and thermal-hydraulic. The theoretical models of neutronics and thermal-hydraulics under steady condition were conducted and calculated by numerical method in this paper. The neutronics model consists of two group neutron diffusion equations for fast and thermal neutron fluxes, and balance equations for six-group delayed neutron precursors considering flow effect. The thermal-hydraulic model was founded on the base of the fundamental conservation laws: the mass, momentum and energy conservation equations. These two models were coupled through the temperature and heat source. The spatial discretization of the above models is based on the finite volume method (FVM), and the thermal-hydraulic equations are computed by SIMPLER algorithm with domain extension method on the staggered grid system. The distribution of neutron fluxes, the distribution of the temperature and velocity and the distribution of the delayed neutron precursors in the core were obtained. The numerical calculated results show that, the fuel salt flow has little effect to the distribution of fast and thermal neutron fluxes and effective multiplication factor; however, it affects the distribution of the delayed neutron precursors significantly, especially long-lived one. In addition, it could be found that the delayed neutron precursors influence the neutronics slightly under the steady condition, and the flow could remove the heat generated by the neutron reactions easily to ensure the reactor safe. The obtained results serve some valuable information for the research and design of this new generation reactor.

Experimental Study of Non-Condensable Effect on Passive Condenser System

2007 ◽  
Author(s):  
Wenzhong Zhou ◽  
Shripad T. Revankar
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Heat Removal ◽  
Scaling Analysis ◽  
Steam Condensation ◽  
Transfer Coefficients ◽  
Specific Design ◽  
Heat Transfer Coefficients ◽  
Removal Capacity ◽  
Safety Systems

One of the engineered safety systems in the advanced boiling water reactor is a passive containment cooling system (PCCS) which is composed of a number of vertical heat exchanger. A set of steam condensation experiments is conducted to evaluate the heat removal capacity of a PCCS condenser. A condensing tube is submerged in a water pool where condensation heat is transferred by secondary boiling heat transfer. The specific design of condensing tube is based on scaling analysis from the PCCS design of ESBWR. The two condensing tubes have same height (0.9m) but different inside diameters, 26.6mm and 52.5mm, respectively. Condensation heat transfer coefficients (HTC) are obtained under various test conditions, such as different primary pressure (150 – 450 kPa), inlet steam flow rate (1 – 5 g/s), air mass fraction (0 – 20%) and tube size (26.6 mm and 52.5 mm ID). The effects of these parameters to condensation performance are evaluated.

Predictive modeling in food process design/Modelos de predicción para el diseño de tratamientos de alimentos

1998 ◽  
Vol 4 (5) ◽  
pp. 303-310 ◽  
Author(s):  
R. Paul Singh ◽  
J. Vijayan
Keyword(s):  
Heat Transfer ◽  
Predictive Modeling ◽  
Core Region ◽  
Operating Conditions ◽  
Food Material ◽  
The Core ◽  
Frying Process ◽  
Product Formulation ◽  
Crust Layer ◽  
Predicted Values

Predictive modeling is a powerful tool in designing and evaluating food processing systems. This technique relies primarily on the fundamental mechanisms governing a process, where the observed mechanisms are expressed with mathematical equations. The mathematical models are converted to a numerical scheme for solution using a computer. The results from predictive modeling are useful in examining the influence of changing operating conditions on the performance of a process. As an illustration, the predictive modeling approach was used in determining rates of heat transfer in foods undergoing frying. The frying process was considered to involve a moving interface inside a food material, between the crust layer and the core region of a food. Conduction heat transfer was considered in the crust layer, and an enthalpy formulation was used for the core region. The predicted values were in good agreement with the experimentally obtained temperature profiles. The model was used to examine the influence of a variety of different processing and product formulation conditions on heat transfer.

Steam Condensation in a Vertical Passive Condenser

2006 ◽  
Author(s):  
Haijing Gao ◽  
Seungmin Oh ◽  
S. T. Revankar
Keyword(s):  
Heat Transfer ◽  
Heat Removal ◽  
Water Pool ◽  
Steam Condensation ◽  
Transfer Coefficients ◽  
Comparison Result ◽  
Heat Transfer Coefficients ◽  
Removal Capacity ◽  
Test Conditions ◽  
Condensation Model

A set of steam condensation experiments is conducted to evaluate the heat removal capacity of a vertical passive condenser. A condensing tube is submerged in a water pool where condensation heat is transferred by secondary boiling heat transfer. Condensation heat transfer coefficients (HTC) are obtained under various test conditions, such as different primary pressure (150 - 450 kPa), inlet steam flow rate (1 - 5 g/s), air mass fraction (0 - 20%) and tube size (26.6 mm and 52.5 mm ID). The effects of these parameters to condensation performance are evaluated in this paper. Experimental data are compared with code predictions from RELAP5 with 2 condensation models. The comparison result shows that an improved condensation model is needed in RELAP5.

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