Determination of Interface Heat Transfer Coefficient for Cylindrical Casting by Using an Inverse Heat Conduction Model

2012 ◽  
Vol 184-185 ◽  
pp. 151-154
Author(s):  
Li Qiang Zhang ◽  
Rong Ji Wang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Solidification Process ◽  
Casting Process ◽  
Theoretical Method ◽  
Interfacial Heat Transfer Coefficient ◽  
Conduction Model ◽  
Interface Heat Transfer ◽  
Cylindrical Casting

For accurate simulation of the casting process with permanent mold, the correct Interfacial Heat Transfer Coefficient (IHTC) is highly important. However, its value is not easily obtained through the experimental or theoretical method in the complex solidification process. In this paper, an inverse conduction model is introduced to determine the IHTC at casting-mold during solidification of the cylindrical casting based on the temperature-measured data. The established inverse model is verified to be a feasible and effective tool for estimation of the metal-mold IHTC during solidification of cylindrical casting by the analysis of calculated results.

The Effect of Air Gap between Casting and Water-Cooled Mold on Interface Heat Transfer Coefficient

2017 ◽  
Vol 893 ◽  
pp. 174-180 ◽  
Author(s):  
Yi Dan Zeng ◽  
Qing Hu Yao ◽  
Xia Wang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Solidification Process ◽  
Casting Process ◽  
Air Gap ◽  
Gap Formation ◽  
Interface Heat Transfer Coefficient ◽  
Interface Heat Transfer ◽  
Interface Heat

Water-cooled casting is a new casting process. It allows even large castings to solidify rapidly, thereby reducing segregation and grain refinement. It has drawn the attention of both domestic and foreign businesses. Heat transfer at the casting/water-cooled mold interface controls the cooling rate of the casting. During the solidification process, because of the contraction that takes place during casting, an air gap can form between the casting and the water-cooled mold. This air gap hinders heat transfer between the casting and the mold, leading to a rapid drop in the interface heat transfer coefficient (IHTC). The purpose of the present study was to assess the effects of the width of the air gap and the duration of gap formation on IHTC. During the experiment, the casting temperature curve was determined in the presence of the interface air gap, and then inverse calculation was performed using PROCAST software to determine the IHTC of casting/water-cooled mold. Results showed that, after the formation of the air gap, IHTC first exhibited a rapid decrease, followed by an increase and then another decrease; IHTC was found to decrease as gap width increased and as the duration of gap formation increased.

Analysis of Interfacial Heat Transfer Coefficient of Green Sand Mold Casting for Aluminum and Tin-Lead Alloys by Using a Lump Capacitance Method

2006 ◽  
Vol 129 (4) ◽  
pp. 595-600 ◽  
Author(s):  
Hsien-Chi Sun ◽  
Long-Sun Chao
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Casting Process ◽  
Sand Mold ◽  
Interfacial Heat Transfer Coefficient ◽  
Interfacial Heat Transfer ◽  
Green Sand ◽  
Air Gaps ◽  
Capacitance Method

During the casting process of green sand mold, air gaps will form between the metal and sand mold. The air gaps will make it difficult to analyze the heat transfer at the mold/metal interface. Generally, an interfacial heat transfer coefficient is employed to evaluate the heat flux transferred across the air gaps. Though the interfacial heat transfer coefficient is highly important, its value is not easily obtained by using the direct experimental or theoretical method. With temperature-measured data, some inverse methods can be used to predict the coefficient. However, the latent heat released and undercooling during the solidification of the molten metal and the moisture of the green sand mold complicate the associated temperature calculations. To overcome this difficulty, a lump capacitance method is proposed in this study to calculate the interfacial heat transfer coefficient for the casting process in green sand mold. Thermalcouples are utilized to measure the temperatures of sand mold and metal. The geometry of casting is cylindrical and the castings are A356 alloy and Sn-20 wt. % Pb alloy. With the predicted interfacial coefficients, the temperature field of the metal was solved numerically. Based on the solidification time, the numerical results are in good agreement with the experimental ones. This verified the feasibility of the proposed method and it can be applied in the future study or design of a casting process.

Research on Simplified Reverse Method for Interfacial Heat Transfer Coefficient (IHTC)

2012 ◽  
Vol 268-270 ◽  
pp. 974-977
Author(s):  
Li Ping Su ◽  
Jian Min Zeng ◽  
Jun Chen ◽  
Wu Kui Gan
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Solidification Process ◽  
Cooling Curve ◽  
Measured Temperature ◽  
Interfacial Heat Transfer Coefficient ◽  
Interfacial Heat Transfer ◽  
Reverse Method

The success of numerical simulation of solidification process depends to a large extent on boundary condition. Interfacial heat transfer coefficient (IHTC) can be used to measure heat resistance between casting and mold. Boundary condition of casting and mold varies with the temperatures during solidification process. However, determination of heat exchange on the boundary is very complicated. A new simple reverse method has been introduced in this paper. A casting with simple geometry acts as the standard sample and a thermal couple records the temperature history at the center of the casting during solidification. The solidification simulation of the casting was conducted with different IHTCs. The equivalent IHTC that best fits the measured temperature can be determined by comparing the measured cooling curve with the calculated one.

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