Effect of DeltaT- and Spatially Varying Heat Transfer Coefficient on Thermal Stress Resistance of Brittle Ceramics Measured by the Quenching Method

1983 ◽  
Vol 66 (1) ◽  
pp. 53-58 ◽  
Author(s):  
T. OZYENER ◽  
K. SATYAMURTHY ◽  
CHARLES EUGENE KNIGHT ◽  
JITENDRA P. SINGH ◽  
D. P. H. HASSELMAN ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Stress ◽  
Transfer Coefficient ◽  
Stress Resistance ◽  
Quenching Method ◽  
Spatially Varying

scholarly journals Thermal Stress and Heat Transfer Coefficient for Ceramics Stalk Having Protuberance Dipping into Molten Metal

2010 ◽  
Vol 4 (8) ◽  
pp. 1198-1213 ◽  
Author(s):  
Nao-Aki NODA ◽  
Hendra ◽  
Wenbin LI ◽  
Yasushi TAKASE ◽  
Hiroki OGURA ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Stress ◽  
Transfer Coefficient ◽  
Molten Metal

scholarly journals Online Fatigue-Monitoring Models with Consideration of Temperature Dependent Properties and Varying Heat Transfer Coefficients

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
HengLiang Zhang ◽  
Shi Liu ◽  
Danmei Xie ◽  
Yangheng Xiong ◽  
Yanzhi Yu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Stress ◽  
Transfer Coefficient ◽  
Green’S Function ◽  
Green's Function ◽  
Fluid Temperature ◽  
Transfer Coefficients ◽  
Temperature Dependent ◽  
Heat Transfer Coefficients

Thermal stress failure caused by alternating operational loads is the one of important damage mechanisms in the nuclear power plants. To evaluate the thermal stress responses, the Green’s function approach has been generally used. In this paper, a method to consider varying heat transfer coefficients when using the Green’s function method is proposed by using artificial parameter method and superposition principle. Time dependent heat transfer coefficient has been treated by using a modified fluid temperature and a constant heat transfer coefficient. Three-dimensional temperature and stress analyses reflecting entire geometry and heat transfer properties are required to obtain accurate results. An efficient and accurate method is confirmed by comparing its result with corresponding 3D finite element analysis results for a reactor pressure vessel (RPV). From the results, it is found that the temperature dependent material properties and varying heat transfer coefficients can significantly affect the peak stresses and the proposed method can reduce computational efforts with satisfactory accuracy.

Prediction of the Tensile Thermal Stress Generation Conditions for Laser Irradiation of Thin Plate Glass with Forced Cooling Based on the Plane Stress Model

2018 ◽  
Vol 12 (4) ◽  
pp. 590-602 ◽  
Author(s):  
Akira Chiba ◽  
◽  
Souta Matsusaka ◽  
Hirofumi Hidai ◽  
Noboru Morita
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Stress ◽  
Transfer Coefficient ◽  
Thin Plate ◽  
Plane Stress ◽  
Plate Glass ◽  
Stress Model ◽  
Forced Cooling ◽  
Tensile Thermal Stress

The tensile thermal stress generated by laser irradiation with forced cooling is critical in the cleavage processing of thin plate glass. In this study, we predicted the conditions for generating tensile thermal stress in laser-induced cleavage of thin plate glass using numerical models from the viewpoint of the cooling and heating areas. An unsteady two-dimensional model was used to predict the temperature distribution and an unsteady plane stress model was used to predict the thermal stress. To generate tensile thermal stress, a cooling area is required behind the heating area. A specific scanning speed is required to yield the maximum tensile stress between the heating and cooling areas. A weak heat transfer coefficient in the cooling area generates tensile thermal stress only in the direction perpendicular to (y direction) the scanning direction of the heat source (x direction). A strong heat transfer coefficient generates tensile thermal stress in both the x and y directions. These tensile thermal stresses are surrounded by horseshoe-shaped compressive thermal stress. The tensile thermal stress can be controlled by selecting an appropriate cooling method for the cooling area.

Three-Dimensional Surface Heat Transfer Coefficient and Thermal Stress Analysis for Ceramics Tube Dipping into Molten Metal

2010 ◽  
Vol 452-453 ◽  
pp. 233-236 ◽  
Author(s):  
Yasushi Takase ◽  
Wen Bin Li ◽  
Hendra ◽  
Hiroki Ogura ◽  
Yusuke Higashi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Stress ◽  
Transfer Coefficient ◽  
Molten Metal ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Surface Heat ◽  
Surface Heat Transfer ◽  
Surface Heat Transfer Coefficient

The low pressure die casting machine has been used in industries because of its low-cost and high efficiency precision forming technique. In the low pressure die casting process is that the permanent die and filling systems are placed over the furnace containing the molten alloy. The filling of the cavity is obtained by forcing the molten metal, by means of a pressurized gas, to rise into a ceramic tube, which connects the die to the furnace. The ceramics tube, called stalk, has high temperature resistance and high corrosion resistance. However, attention should be paid to the thermal stress when the ceramics tube is dipped into the molten metal. It is important to reduce the risk of fracture that may happen due to the thermal stresses. To calculate the thermal stress, it is necessary to know the surface heat transfer coefficient when the ceramics tube dips into the molten metal. In this paper, therefore, the three-dimensional thermo-fluid analysis is performed to calculate surface heat transfer coefficient correctly. The finite element method is applied to calculate the thermal stresses when the tube is dipped into the crucible with varying dipping speeds and dipping directions. It is found that the thermal stress can be reduced by dipping slowly when the tube is dipped into the molten metal.

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