Three-Dimensional Numerical Study of Overheating of Two Intermediate Temperature P-AS-SOFC Geometrical Configurations

2021 ◽  
pp. 186-222
Author(s):  
Youcef Sahli ◽  
Bariza Zitouni ◽  
Ben Moussa Hocine
Keyword(s):  
Thermal Stresses ◽  
Numerical Study ◽  
Three Dimensional ◽  
Intermediate Temperature ◽  
Stable Operation ◽  
Fortran Code ◽  
Proposed Model ◽  
Heat Transfer Phenomenon ◽  
And Performance ◽  
Result Analysis

The purpose of this work is to perform a three-dimensional and stationary numerical study of the heat transfer phenomenon in the planar anode-supported solid oxide fuel cells operating at intermediate temperature (IT-P-AS-SOFC). With particular interest to evaluate and localize the maximum and minimum temperatures in a single cell during their stable operation according to two geometrical configuration types, repetition, and symmetry of the cell stages to determine the best configuration that minimizes and produces more homogeneous thermal stresses and logically improves their lifetime and performance. The considered heat sources are mainly due to electrical overpotentials (Ohm, activation, and concentration). The results are obtained according to a FORTRAN code based on the proposed model that is numerically modeled using the finite difference method. From the obtained result analysis, the achieved temperature values by IT-P-AS-SOFC with cell stages repetition are greater than obtained by IT-P-AS-SOFC with cell stages symmetry.

Analysis of Intermediate Temperature Solid Oxide Fuel Cell Transport Processes and Performance

2005 ◽  
Vol 127 (12) ◽  
pp. 1380-1390 ◽  
Author(s):  
Jinliang Yuan ◽  
Bengt Sundén
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Electrical Power ◽  
Three Dimensional ◽  
Transport Processes ◽  
Solid Oxide ◽  
Intermediate Temperature ◽  
Oxide Fuel ◽  
Modeling And Analysis ◽  
And Performance

A new trend in recent years is to reduce the solid oxide fuel cell (SOFC) operating temperature to an intermediate range by employing either a thin electrolyte, or new materials for the electrolyte and electrodes. In this paper, a numerical investigation is presented with focus on modeling and analysis of transport processes in planar intermediate temperature (IT, between 600 and 800°C) SOFCs. Various transport phenomena occurring in an anode duct of an ITSOFC have been analyzed by a fully three-dimensional calculation method. In addition, a general model to evaluate the stack performance has been developed for the purpose of optimal design and/or configuration based on specified electrical power or fuel supply rate.

Blade Tip Carving Effects on the Aero-Thermal Performance of a Transonic Turbine

2013 ◽  
Author(s):  
C. De Maesschalck ◽  
S. Lavagnoli ◽  
G. Paniagua
Keyword(s):  
High Speed ◽  
Thermal Stresses ◽  
Numerical Study ◽  
Three Dimensional ◽  
Turbine Rotor ◽  
Geometrical Parameters ◽  
Complex Flow ◽  
Turbine Rotor Blade ◽  
Blade Tip ◽  
Transonic Turbine

Tip leakage flows in unshrouded high speed turbines cause large aerodynamic penalties, induce significant thermal loads and give rise to intense thermal stresses onto the blade tip and casing endwalls. In the pursuit of superior engine reliability and efficiency, the turbine blade tip design is of paramount importance and still poses an exceptional challenge to turbine designers. The ever-increasing rotational speeds and pressure loadings tend to accelerate the tip flow velocities beyond the transonic regime. Overtip supersonic flows are characterized by complex flow patterns, which determine the heat transfer signature. Hence, the physics of the overtip flow structures and the influence of the geometrical parameters on the overtip flow require further understanding to develop innovative tip designs. Conventional blade tip shapes are not adequate for such high speed flows and hence, potential for enhanced performances lays in appropriate tip shaping. The present research aims to quantify the prospective gain offered by a fully contoured blade tip shape against conventional geometries such as a flat and squealer tip. A detailed numerical study was conducted on a modern transonic turbine rotor blade (Reynolds number is 5.5 × 105, relative exit Mach number is 0.9) by means of three-dimensional Reynolds-Averaged Navier-Stokes calculations. The novel contoured tip geometry was designed based on a 2D tip shape optimization in which only the upper 2% of the blade span was modified. This study yields a deeper insight into the application of blade tip carving in high speed turbines and provides guidelines for future tip designs with enhanced aerothermal performances.

scholarly journals Spatial Reasoning Based on 3D-ICSRM Model

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Yongshan Liu ◽  
Xiang Gong ◽  
Dehan Kong
Keyword(s):  
Spatial Reasoning ◽  
Three Dimensional ◽  
Spatial Relationship ◽  
Three Dimensional Objects ◽  
Proposed Model ◽  
Relationship Model ◽  
Composite Models ◽  
Differentiation Degree ◽  
And Performance ◽  
Reasoning Algorithm

The existing spatial relationship composite models have defects in both cognitive habits and differentiation degree when describing the spatial relationship between the three dimensional objects. These defects can cause inaccuracy in the process of spatial reasoning. In order to solve this problem, this paper proposes a Three-Dimensional Improved Composite Spatial Relationship Model (3D-ICSRM). Then a high-precision spatial relationship reasoning algorithm is presented based on this model, which combines qualitative and quantitative analyses. Finally, both the correctness and performance advantages of spatial reasoning algorithm are verified by experiments based on this proposed model.

Blade Tip Carving Effects on the Aerothermal Performance of a Transonic Turbine

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
C. De Maesschalck ◽  
S. Lavagnoli ◽  
G. Paniagua
Keyword(s):  
High Speed ◽  
Thermal Stresses ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Geometrical Parameters ◽  
Complex Flow ◽  
Leakage Flows ◽  
Blade Tip ◽  
Exit Mach Number

Tip leakage flows in unshrouded high speed turbines cause large aerodynamic penalties, induce significant thermal loads and give rise to intense thermal stresses onto the blade tip and casing endwalls. In the pursuit of superior engine reliability and efficiency, the turbine blade tip design is of paramount importance and still poses an exceptional challenge to turbine designers. The ever-increasing rotational speeds and pressure loadings tend to accelerate the tip flow velocities beyond the transonic regime. Overtip supersonic flows are characterized by complex flow patterns, which determine the heat transfer signature. Hence, the physics of the overtip flow structures and the influence of the geometrical parameters require further understanding to develop innovative tip designs. Conventional blade tip shapes are not adequate for such high speed flows and hence, potential for enhanced performances lays in appropriate tip shaping. The present research aims to quantify the prospective gain offered by a fully contoured blade tip shape against conventional geometries such as a flat and squealer tip. A detailed numerical study was conducted on a modern rotor blade (Reynolds number of 5.5 × 105 and a relative exit Mach number of 0.9) by means of three-dimensional (3D) Reynolds-averaged Navier–Stokes (RANS) calculations. Two novel contoured tip geometries were designed based on a two-dimensional (2D) tip shape optimization in which only the upper 2% of the blade span was modified. This study yields a deeper insight into the application of blade tip carving in high speed turbines and provides guidelines for future tip designs with enhanced aerothermal performances.

Effect of Wind Shear to Horizontal Axis Wind Turbine Aerodynamic

2014 ◽  
Vol 521 ◽  
pp. 99-103
Author(s):  
Ling Zhang ◽  
Hui Xia Sheng ◽  
Da Fei Guo
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Shear ◽  
Numerical Study ◽  
Three Dimensional ◽  
Horizontal Axis ◽  
Power Calculation ◽  
Horizontal Axis Wind Turbine ◽  
Horizontal Axis Wind Turbines ◽  
And Performance

A three-dimensional unsteady numerical study of the streaming flow field of the1.2 MW horizontal axis wind turbines which operation in the 11.26 m/s under the uniform wind and the shear wind have been carried out in this paper. according to the simulation results to understand the effect of uniform flow and the dynamic wind shear flow to the output power of wind turbine and the aerodynamics. results showed that: Under the uniform wind,Wind turbine power calculation values are in good agreement with the design value ,Wind turbines under the influence of wind shear can lead to change in load and performance on the surface of the blade.

scholarly journals Influence of contact parameters in fretting-fatigue contact 3D problems

2020 ◽  
Vol 15 (55) ◽  
pp. 228-240
Author(s):  
Fella Hamadouche ◽  
Habib Benzaama ◽  
Mohamed Mokhtari ◽  
Miloud Abbes Tahar
Keyword(s):  
Stress Intensity ◽  
Numerical Study ◽  
Fatigue Behavior ◽  
Three Dimensional ◽  
Fretting Fatigue ◽  
Parametric Model ◽  
Intensity Factors ◽  
Full Contact ◽  
Fortran Code ◽  
Contact Parameters

A numerical study on the influence of contact parameters on fretting fatigue behavior is carried out by using a new method SFEM (Stretching Finite Element Method) is presented in this article. Several parameters are made to vary: geometric shapes of the mesh, materials and contact parameters. The three-dimensional parametric model is composed by specimen and a pad in full contact. A Fortran Code is used to generate the parametric mesh. The stress intensity factors are calculated by varying the above contact parameters and the stress intensity factor under modes I, II and III are computed..

The Influence of Cognitive and Affective Reactions to Feedback on Subsequent Goals

2010 ◽  
Vol 15 (2) ◽  
pp. 121-131 ◽  
Author(s):  
Remus Ilies ◽  
Timothy A. Judge ◽  
David T. Wagner
Keyword(s):  
Performance Feedback ◽  
Business School ◽  
Structural Equation ◽  
Emotional Reactions ◽  
Equation Model ◽  
Proposed Model ◽  
And Performance ◽  
Dispositional Measure ◽  
The Relationship ◽  
Reactions To Feedback

This paper focuses on explaining how individuals set goals on multiple performance episodes, in the context of performance feedback comparing their performance on each episode with their respective goal. The proposed model was tested through a longitudinal study of 493 university students’ actual goals and performance on business school exams. Results of a structural equation model supported the proposed conceptual model in which self-efficacy and emotional reactions to feedback mediate the relationship between feedback and subsequent goals. In addition, as expected, participants’ standing on a dispositional measure of behavioral inhibition influenced the strength of their emotional reactions to negative feedback.

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