Effect of Coking Size on the Thermal Diffusion and Stress Distribution of Cr25Ni35Nb and Cr35Ni45Nb Austenitic Steels

2015 ◽  
Vol 750 ◽  
pp. 192-197 ◽  
Author(s):  
Li Min Shen ◽  
Jian Ming Gong ◽  
Huan Sheng Liu
Keyword(s):  
Thermal Stress ◽  
Austenitic Steel ◽  
Thermal Diffusion ◽  
Austenitic Steels ◽  
Thermal Stress Field ◽  
Operation Period ◽  
Furnace Tube ◽  
Subsequent Measurement ◽  
Abaqus Code ◽  
Long Operation

Cr25Ni35Nb and Cr35Ni45Nb austenitic steels, used as furnace tube material in the ethylene pyrolysis furnace, generally suffer from coking during the long operation period. In the present paper, for coked Cr25Ni35Nb and Cr35Ni45Nb austenitic steel, using the finite element ABAQUS code, a sequentially coupled thermal stress procedure was developed to calculate distribution of the temperature and thermal stress field. The results show that thermal diffusion property of Cr25Ni35Nb and Cr35Ni45Nb steel deteriorates obviously with coking layer increasing. Radial bulge and rupture at local field would generate due to excess temperature for applied subsequent measurement. Maximum stress distribute along the cross-section of coking layer and metal matrix. Finally, the critical depth of coking layer of Cr25Ni35Nb and Cr35Ni45Nb austenitic steel are predicted when decoking measurement must be executed.

Thermodynamic Analysis of Damaged Thermal Protection System Tiles

2011 ◽  
Vol 211-212 ◽  
pp. 352-356
Author(s):  
Zhen Qing Wang ◽  
Xiang Nan Meng ◽  
Hong Qing Lv
Keyword(s):  
Temperature Field ◽  
Thermal Stress ◽  
Thermal Protection ◽  
Space Shuttle ◽  
Thermal Protection System ◽  
Protection System ◽  
Aerodynamic Heating ◽  
Insulation Material ◽  
Thermal Stress Field ◽  
Abaqus Code

Ceramic insulating tile is the main insulation material used on space shuttle thermal protection system at present, but this material has low strength, high brittleness and easy to be damaged. So the study of thermodynamic response of damaged rigid ceramic insulating tiles is very important. In this paper the temperature field and thermal stress field of the damaged ceramic insulating tiles under aerodynamic heating are simulated by ABAQUS code. The analyzed results indicate that the sharp degree of the damage shape has minor influence on the temperature field, but is more significant for the maximum thermal stress. Meanwhile the larger loading is, the bigger influence is.

Improvement of Radiation Resistance of Multijunction GaInP/Ga(In)As/Ge Solar Cells with Application of Bragg Reflectors

2010 ◽  
Vol 74 ◽  
pp. 225-230 ◽  
Author(s):  
Vladimir M. Lantratov ◽  
Viktor M. Emelyanov ◽  
Nikolay A. Kalyuzhnyy ◽  
Sergey A. Mintairov ◽  
Maxim Z. Shvarts
Keyword(s):  
Solar Cells ◽  
Radiation Resistance ◽  
Radiation Treatment ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Charge Carriers ◽  
Bragg Reflectors ◽  
Multijunction Solar Cells ◽  
Operation Period ◽  
Long Operation

Feasibility to increase the radiation resistance of multijunction solar cells in using Bragg reflectors has been shown. Two designs of Bragg reflectors for multijunction solar cells, which allow ensuring in the Ga(In)As subcell base an effective collection of minority charge carriers at the decrease of their diffusion length caused by radiation treatment, have been investigated. Influence of subcells’ thicknesses of n-p GaInP/Ga(In)As/Ge solar cell under 1 MeV electron irradiation with fluences up to 3•1015 cm–2 on short circuit current was considered. Optimal thicknesses of GaInP and GaInAs subcells with Bragg reflectors, depending on the rated operation period on the geostationary orbit, were estimated. It has been shown that such an optimization allows to achieve efficiency at long operation of solar cells on the orbit noticeably higher than that of non-optimized cells.

scholarly journals Thermal–Fluid–Solid Coupling Analysis on the Temperature and Thermal Stress Field of a Nickel-Base Superalloy Turbine Blade

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3315
Author(s):  
Liuxi Cai ◽  
Yao He ◽  
Shunsen Wang ◽  
Yun Li ◽  
Fang Li
Keyword(s):  
Thermal Stress ◽  
Temperature Gradient ◽  
Turbine Blade ◽  
Turbine Blades ◽  
Nickel Base Superalloy ◽  
Barrier Coating ◽  
Thermal Stress Field ◽  
Nickel Base ◽  
Stress Damage ◽  
Superalloy Turbine Blade

Based on the establishment of the original and improved models of the turbine blade, a thermal–fluid–solid coupling method and a finite element method were employed to analyze the internal and external flow, temperature, and thermal stress of the turbine blade. The uneven temperature field, the thermal stress distribution characteristics of the composite cooling turbine blade under the service conditions, and the effect of the thickness of the thermal barrier coating (TBC) on the temperature and thermal stress distributions were obtained. The results show that the method proposed in this paper can better predict the ablation and thermal stress damage of turbine blades. The thermal stress of the blade is closely related to the temperature gradient and local geometric structure of the blade. The inlet area of the pressure side-platform of the blade, the large curvature region of the pressure tip of the blade, and the rounding between the blade body and the platform on the back of the blade are easily damaged by thermal stress. Cooling structure optimization and thicker TBC thickness can effectively reduce the high temperature and temperature gradient on the surface and inside of the turbine blade, thereby reducing the local high thermal stress.

scholarly journals Laser Welding Of Finned Tubes Made Of Austenitic Steels

2015 ◽  
Vol 60 (3) ◽  
pp. 1807-1812
Author(s):  
M. Stolecki ◽  
H. Bijok ◽  
Ł. Kowal ◽  
J. Adamiec
Keyword(s):  
Laser Welding ◽  
Austenitic Steel ◽  
Technological Process ◽  
Welded Joints ◽  
Austenitic Steels ◽  
Tube Production ◽  
High Quality ◽  
Manufacturing Costs ◽  
Finned Tubes

Abstract This paper describes the technology of welding of finned tubes made of the X5CrNi1810 (1.4301) austenitic steel, developed at Energoinstal SA, allowing one to get high quality joints that meet the requirements of the classification societies (PN-EN 15614), and at the same time to significantly reduce the manufacturing costs. The authors described an automatic technological line equipped with a Trumph disc laser and a tube production technological process. To assess the quality of the joints, one performed metallographic examinations, hardness measurements and a technological attempt to rupture the fin. Analysis of the results proved that the laser-welded finned tubes were performed correctly and that the welded joints had shown no imperfections.

Effects of Scanning Patterns on the Thermal/Stress Field during Laser Solid Forming T-Shape Chord of Ti-6Al-4V Alloy

2014 ◽  
Vol 41 (7) ◽  
pp. 0703003
Author(s):  
姜亚琼 Jiang Yaqiong ◽  
林鑫 Lin Xin ◽  
马良 Ma Liang ◽  
谭华 Tan Hua ◽  
杨海欧 Yang Haiou ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Stress Field ◽  
Laser Solid Forming ◽  
Thermal Stress Field

Analysis of Thermal Shock on Nuclear Power Station Pump

1998 ◽  
Author(s):  
Cao Qing ◽  
Wu Yimin ◽  
Zhang Zhimin
Keyword(s):  
Thermal Stress ◽  
Thermal Shock ◽  
Nuclear Power Station ◽  
Nuclear Power ◽  
Thermal Deformation ◽  
Power Station ◽  
Thermal Stress Field ◽  
Thermoelastic Equation ◽  
Thermal Shock Problem ◽  
Qualitative Discussion

In this paper, a heat conduction equation and a dynamic thermoelastic equation are briefly deduced and established based on Continuum Mechanics. First, an qualitative discussion is emphatically centered around the couple term and the dynamic term of the equation by means of the dimensional analysis and by considering the combination of the characteristics of the materials and of the thermal load effected on the nuclear power station pump under study. Second, formulations of the FEM for non-coupled heated equations and quasi-static thermoelastic equations are derived in this paper. Third, a half space thermal shock problem is used as a computational example in the highlighted research on the varying behavior of the dynamic thermal stress on the temperature slope. The conclusion of the paper provides reliable justification for applying the numerical method. Finally, the distribution and variety of the temperature field, the thermal stress field and the thermal deformation field at various transient moments on the pump are given.

Calculation and Analysis of 2-D Thermal Stress Field in Induction Motor with Compound Cage Rotor under Different Load

2011 ◽  
Vol 117-119 ◽  
pp. 97-100
Author(s):  
Jun Ci Cao ◽  
Rong Chao Qian ◽  
Wei Li Li
Keyword(s):  
Finite Element ◽  
Thermal Stress ◽  
Stress Field ◽  
Induction Motor ◽  
Reference Value ◽  
Single Site ◽  
Compound Material ◽  
Thermal Stress Field ◽  
New Type ◽  
Cage Rotor

3kW two poles induction motor with compound cage rotor is illustrated in this paper, and 2-D thermal stress field of induction motor rotor is calculated and analyzed by finite element. Contrasting with common induction motor, induction motor with compound cage rotor has specific rotor shot shape and the bar is comprised of the upper compound material and the lower cast aluminium, which cause distribution of thermal stress is special. The motor with the rotor shot of compound material laid at single site is chosen to analyzing. The maximum thermal stress in the bar is calculated at different load, and the distribution of thermal stress in the bar is analyzed at rate load. The law of distribution of thermal stress in the bar has same reference value for designing new type of induction motor.

Investigation on Temperature Field and Thermal Stress of Dish Solar Concentrator’s Focal Region

2011 ◽  
Vol 148-149 ◽  
pp. 20-23
Author(s):  
Xing Zhi Wang ◽  
Yong Shuai ◽  
Fu Qiang Wang ◽  
Chun Liang Yu
Keyword(s):  
Temperature Field ◽  
Thermal Stress ◽  
Stress Field ◽  
Infrared Camera ◽  
Radiant Heat ◽  
Focal Region ◽  
Solar Concentrator ◽  
Flux Function ◽  
Thermal Stress Field ◽  
Good Accordance

Depending on the solar radiant flux and velocity measured in Harbin, with finite element method, use a modified radiant heat flux function to calculate the temperature field of a plate on the focal region of a dish solar concentrator. Compared the result with picture taken by infrared camera, there is a good accordance between them. The temperature field is used as the loading parameters to calculate the thickness’s impact on the thermal stress field in the plate. When the value of the thickness increases, the maximum values of the stress increase, but the overall stress field tend to decrease.

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