scholarly journals Design Optimization of a Helical Coil Gas Cooler Based on the Results of CFD Modeling of Erosion Wear

2022 ◽  
Vol 2150 (1) ◽  
pp. 012017
Author(s):  
V A Mikula ◽  
G E Maslennikov ◽  
T F Bogatova
Keyword(s):  
Design Optimization ◽  
Maximum Level ◽  
Impact Angle ◽  
Flow Path ◽  
Combined Cycle ◽  
Cfd Modeling ◽  
Helical Coil ◽  
Baffle Plate ◽  
Erosion Wear ◽  
Structural Element

Abstract Simulation of erosion wear and design optimization have been performed for a convective gas cooler with a helical coil. Based on the results of simulation of the standard gas cooler design with a flat baffle used in Shell gasification-based combined cycle unit, it is concluded that the particle impact angle is the main factor determining the erosion maximum. To reduce erosion, it is necessary to install a structural element instead of the flat baffle to align the flow path of ash particles at the inlet to the gas cooler. The results of simulation for various baffle shapes show that a hemispherical baffle is optimal. The use of a hemispherical baffle plate made it possible to align the ash particle flow path at the inlet to the gas cooler channels and reduce the maximum level of erosion by a factor of almost 4 compared to the standard geometry of the baffle plate.

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.

Novel Liquid Fuel HVOF Torches Fueled with Ethanol: Optimization and Erosion Wear Response of Cr3C2-NiCr Coatings

2021 ◽  
Author(s):  
Shaowu Liu ◽  
Michel Moliere ◽  
Hanlin Liao
Keyword(s):  
Flow Rate ◽  
Feed Rate ◽  
Impact Angle ◽  
Oxygen Flow Rate ◽  
Oxygen Flow ◽  
Standoff Distance ◽  
Wear Loss ◽  
Erosion Wear ◽  
Powder Feed Rate ◽  
Powder Feed

Abstract In this work; a novel liquid fuel HVOF process fueled with ethanol was used to prepare 75wt%Cr3C2–25wt%NiCr coatings on AISI304 stainless steel substrate. Taguchi method was employed to optimize the spray parameters (ethanol flow rate; oxygen flow rate; powder feed rate and standoff distance) to achieve better erosion resistance at 90° impact angle. The results indicated that ethanol flow rate and oxygen flow rate were identified as the highly contributing parameters on the erosion wear loss. The important sequence of the spray parameter is ethanol flow rate > oxygen flow rate > standoff distance > powder feed rate. The optimal spray parameter (OSP) for minimum erosion wear loss was obtained under ethanol flow rate of 28slph; oxygen flow rate of 420slpm; powder feed rate of 76.7 g/min and standoff distance of 300mm. The phase composition; microstructure; hardness; porosities; and the erosion wear behaviors of the coatings have been studied in detail. Besides; erosion wear testing of the optimized coating was conducted at 30°; 60° and 90° impact angle using air jet erosion testing machine. The SEM images of the erodent samples were taken to analyze the erosion mechanism.

Transport Enhancement in Tunable Laser Cavity Sensor

2002 ◽  
Author(s):  
M. Sigurdson ◽  
C. Meinhart ◽  
D. Wang ◽  
X. Liu ◽  
J. J. Feng ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Design Optimization ◽  
Tunable Laser ◽  
Laser Cavity ◽  
Cfd Modeling ◽  
Physical Processes ◽  
Transport Enhancement ◽  
Computational Fluid Dynamics Cfd ◽  
Electrothermal Flow

Dielectrophoresis and Electrothermal Flow are two physical processes investigated for enhancing transport of antigen to a region of immobilized conjugate antibodies on an immunosensor surface. Computational fluid dynamics (CFD) modeling is employed to understand these phenomena in detail to aid in the design optimization of the device.

scholarly journals Experimental Evaluation of Erosion of Gunmetal under Asymmetrical Shaped Sand Particle

2015 ◽  
Vol 2015 ◽  
pp. 1-31 ◽  
Author(s):  
Mohammad Asaduzzaman Chowdhury ◽  
Uttam Kumar Debnath ◽  
Dewan Muhammad Nuruzzaman ◽  
Md. Monirul Islam
Keyword(s):  
Impact Velocity ◽  
Wear Behavior ◽  
Maximum Level ◽  
Impact Angle ◽  
Operating Conditions ◽  
Silica Sand ◽  
Sand Particle ◽  
Damage Propagation ◽  
Erosion Efficiency ◽  
The Impact

The erosion characteristics of gunmetal have been evaluated practically at different operating conditions. Asymmetrical silica sand (SiO2) is taken into account as erodent within range of 300–600 μm. The impact velocity within 30–50 m/sec, impact angle 15–900, and stand off distance 15–25 mm are inspected as other relevant operating test conditions. The maximum level of erosion is obtained at impact angle 15° which indicates the ductile manner of the tested gunmetal. The higher the impact velocity, the higher the erosion rate as almost linear fashion is observed. Mass loss of gunmetal reduces with the increase of stand-off distance. A dimensional analysis, erosion efficiency (η), and relationship between friction and erosion indicate the prominent correlation. The test results are designated using Taguchi’s and ANOVA concept.S/Nratio indicates that there are 1.72% deviations that are estimated between predicted and experimental results. To elaborately analyze the results, ANN and GMDH methods are mentioned. After erosion process of tested composite, the damage propagation on surfaces is examined using SEM for the confirmation of possible nature of wear behavior. The elemental composition of eroded test samples at varying percentage of gunmetal is analyzed by EDX analysis.

Solid Particle Erosion of Selected HVOF Sprayed Coatings

2016 ◽  
Vol 827 ◽  
pp. 39-46
Author(s):  
Šárka Houdková ◽  
Zdeněk Česánek ◽  
Pavel Polach
Keyword(s):  
Wear Resistance ◽  
Wear Mechanism ◽  
Thermal Spraying ◽  
Impact Angle ◽  
Erosion Wear ◽  
Wear Properties ◽  
Experimental Development ◽  
The Subject ◽  
The Impact ◽  
Super Alloy

The paper involves the subject and the chosen results of up to now solving of work package “Development of advanced surface treatment of components used in parts of turbines working under the condition of operational temperatures of steam using the HP/HVOF technology of thermal spraying” of the Competence Centre project “Centre of Research and Experimental Development of Reliable Energy Production”. The subject belongs to the field of material engineering and results of solving contribute to fulfilling the main project aim, which is a long time safeguarding of safe, reliable and financially available both classical thermal and nuclear sources of electric power, which consists in extending service life of existing and building new turbo generator blocks. The erosion wear resistance is one of the areas, which were observed. The impact of hard particles on the surface under variable impact angles was simulated in laboratory conditions using an in-house equipment. The wear resistance of selected HVOF sprayed hardmetal and super-alloy coatings was measured and the wear mechanism was evaluated. A strong influence of impact angle on both material volume loss and wear mechanism was monitored. The superior erosion wear properties of super-alloy coatings were proved, regardless the higher hardness of hardmetal coatings.

Boundary Layer Effects in the Modeling of Semi-Submersible Columns

2018 ◽  
Author(s):  
Samuel Holmes
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Angle Of Attack ◽  
Cfd Modeling ◽  
Structural Element ◽  
Roughness Effects ◽  
Vertical Column ◽  
Drag Forces ◽  
Reynolds Number Effects ◽  
Lift And Drag

A common structural element encountered in semisubmersible designs is a rectangular vertical column with rounded corners. The time-averaged drag and oscillating lift and drag forces on such columns are strongly influenced by the location of the lines of flow separation on the column and hence the angle of attack of the incoming flow and the corner radius. In this paper we examine published wind tunnel data to illustrate these effects which include angle of attack and Reynolds number effects. This examination suggests that care must be exercised modeling flows around these elements. Also, the data suggest that Reynolds number effects and surface roughness effects may distort the results of scaled experiments. We use CFD simulations first to model the existing data and then to explore the possible changes in hydrodynamic properties due to Reynolds number and boundary layer effects. Recommendations are made regarding the physical and CFD modeling of the flow over these structures.

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