scholarly journals Analysis of a helical coil once-through molten salt steam generator: Experimental results and heat transfer evaluation

2016 ◽  
Author(s):  
B. Seubert ◽  
E. Rojas ◽  
E. Rivas ◽  
W. Gaggioli ◽  
L. Rinaldi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Molten Salt ◽  
Steam Generator ◽  
Experimental Results ◽  
Helical Coil

Thermal Hydraulic Studies on Helical Coil Steam Generator by CFD

2011 ◽  
Author(s):  
Sooyun Joh
Keyword(s):  
Heat Transfer ◽  
Steam Generator ◽  
Nuclear Reactor ◽  
Complex Geometry ◽  
Transport Model ◽  
Cfd Modeling ◽  
Helical Coil ◽  
Power Module ◽  
Flux Boundary Condition ◽  
Nuclear Core

NuScale Power, Inc. is commercializing a 45 Megawatt electric light water nuclear reactor NuScale Power Module (NPM). Each NPM includes a containment vessel, a reactor vessel, a nuclear reactor core, an integral steam generator, and an integral pressurizer. The NuScale Power Module is cooled by natural circulation. The primary coolant in the Reactor Pressure Vessel is heated in the nuclear core, it rises through a central riser, it spills over and encounters the helical coil steam generator, it is cooled as steam is generated inside the steam generator, and it is again heated in the nuclear core. The Steam Generator also must be designed to provide adequate heat transfer, to allow adequate primary reactor coolant flow, and to provide adequate steam flow to produce the required power output. This paper presents the CFD results that describe the transport phenomena on the heat transfer and fluid flow dynamics in helical coil steam generator tubes. The ultimate goal of the CFD modeling is to predict the steam outlet conditions associated with the chosen helical coil tube geometries, solving the primary and secondary flow region together coupled with the helical coil tube. However, current studies are focused on the primary side with the heat flux boundary condition assigned on the outer surface of the helical coil steam generator. In this study, the ANSYS CFX v. 12.1 [1] was used to solve the three-dimensional mass, momentum and energy equations. The helical coil steam generator has complex geometry and modeling entire geometry requires the enormous memory that is beyond our hardware capability and is not practical. Therefore, geometry was limited to 1 degree of the wedge and 5% of the total length in the middle. Only external flow, single phase flow around the helical coils, is simulated using the standard k-ε model and shear stress transport model. From the results of the numerical simulation, the pressure drop and temperature profiles were determined. It is important to understand thermal hydraulic phenomena for the design and performance prediction of the reactor internal.

Heat transfer performance of U-tube molten salt steam generator

2020 ◽  
Vol 160 ◽  
pp. 120200
Author(s):  
Yukun Zou ◽  
Jing Ding ◽  
Weilong Wang ◽  
Duujong Lee ◽  
Jianfeng Lu
Keyword(s):  
Heat Transfer ◽  
Molten Salt ◽  
Steam Generator ◽  
Heat Transfer Performance ◽  
Transfer Performance

scholarly journals Heat transfer characteristics of molten salt flowing in steam generator

2021 ◽  
pp. 225-225
Author(s):  
Shiquan He ◽  
Linhao Wei ◽  
Jianfeng Lu ◽  
Weilong Wang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Molten Salt ◽  
Steam Generator ◽  
Inlet Temperature ◽  
Heat Transfer Characteristics ◽  
Shell And Tube ◽  
Double Pipe ◽  
The Heat Transfer Coefficient

The paper respectively investigated the heat transfer characteristics of molten salt flowed in shell-and-tube and double-pipe steam generator. The shell-and-tube steam generator had seven tubes and molten salt flowed outside the tubes, while the double-pipe steam generator had two concentric tubes and molten salt flowed in the annular duct formed by two tubes. Inlet temperature of molten salt ranged from 270?C to 420?C. The experimental results showed the effect of temperature on heat transfer coefficient was more significant in the double-pipe steam generator compared to the shell-and-tube steam generator. The heat transfer coefficient firstly increased and then decreased as the increase of temperature. Further numerical study was conducted and the results showed, in the shell-and-tube steam generator, the flow is disturbed by the tube bundle and the boundary layer near the inner wall is deformed, so the temperature of molten salt cannot obviously affect the heat transfer. In the double-pipe steam generator, an opposite flow was generated in the near cooled wall region by the buoyancy force. When the inlet temperature was below 315?C, the velocity of the opposite flow was quite low. In this stage, the heat transfer coefficient increased with the increase of temperature. When the inlet temperature continues to rise to 390?C, the opposite flow was enhanced and a stable layer with low velocity formed between the mainstream and the inner cooled wall, resulting increase of heat transfer resistance and impairment of heat transfer coefficient.

scholarly journals Hybridization of CSP Plants: Characterization of a Molten Salt Heater for Binary and Ternary Nitrate Salt Mixtures Fueled with Gas/Biogas Heaters

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7652
Author(s):  
Alberto Giaconia ◽  
Irena Balog ◽  
Giampaolo Caputo
Keyword(s):  
Heat Transfer ◽  
Molten Salt ◽  
Molten Salts ◽  
Alternative Energy ◽  
Experimental Tests ◽  
Experimental Results ◽  
Heat Transfer Fluid ◽  
Utilization Factor ◽  
Alternative Energy Sources ◽  
Salt Mixtures

Hybridization of CSP plants with alternative energy sources (fuels) represents a means to improve flexibility of operation, power dispatchability and utilization factor of the plant. New generation CSP plants make use of molten salts as Heat Transfer Fluid (HTF) besides Thermal Energy Storage (TES) medium. Therefore, proper interfaces should be developed to effectively transfer the heat from the back-up source to the molten salt. This paper presents the results obtained in the experimental validation of an innovative gas-fueled Molten Salt Heater (MSH) prototype. The objective of this research is to validate the MSH design, where the specific properties of molten salts (compared to other HTFs, e.g., thermal oils) have to be taken into account. The developed reduced-scale MSH (90 kW thermal) consists of a heat exchanger with the molten salt flowing inside finned tubes cross-flowed with the hot flue gas generated in an upstream combustion chamber. LPG or a biogas-like mixture has been used as gas fuel. Experimental results have been obtained with two different molten salt mixtures: the “solar salt” binary mixture (NaNO3/KNO3, 60/40%w) typically used in CSP applications (up to 565 °C) and the ternary mixture known as Hitec XL® containing sodium/potassium/calcium nitrates (NaNO3/KNO3/Ca(NO3)2, 15/43/42%w) characterized by lower freezing temperatures. Experimental tests have been carried out changing some operative parameters like the flow rate of the molten salt (0.45–0.94 kg/s), the inlet temperatures of the molten salt (303–445 °C) and of the hot gas (596–632 °C). For both molten salt mixtures, it was demonstrated that heat transfer correlations based on the Dittus-Boelter equation allow to predict experimental results with <10% deviation between experimental and theoretical values of the heat transfer coefficient.

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