Numerical simulation of heat transfer and fluid flow of molten metal in MMA–St copolymer lost foam casting process

2010 ◽  
Vol 210 (14) ◽  
pp. 2071-2080 ◽  
Author(s):  
Ali Charchi ◽  
Mostafa Rezaei ◽  
Siyamak Hossainpour ◽  
Jamal Shayegh ◽  
Sohrab Falak
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Fluid Flow ◽  
Molten Metal ◽  
Casting Process ◽  
Lost Foam Casting ◽  
Lost Foam

Numerical Simulation of Molten Metal-Polymeric Foam Interface Velocity During Lost Foam Casting

2001 ◽  
Author(s):  
Sayavur I. Bakhtiyarov ◽  
Ruel A. Overfelt
Keyword(s):  
Molten Metal ◽  
Flow Model ◽  
Interface Velocity ◽  
Casting Process ◽  
Lost Foam Casting ◽  
Foam Material ◽  
Polymeric Foam ◽  
Gaseous Products ◽  
3D Software ◽  
Lost Foam

Abstract A novel multiphase flow model is presented for describing the pyrolisis of polymeric foam material in a lost foam casting process. FLOW-3D software (Flow Science, Inc.) has been used to simulate liquid metal filling dynamics and the molten metal-polymeric foam interface velocity in foam patterns of rectangular shape. The effect of the degradation gaseous products on the molten metal-polymeric foam interface velocity was taken into consideration through specially written sub-routing program. The results of the simulations are compared with the previously obtained experimental data for the lost foam iron casting.

Measurement of Kinetic Zone Temperature and Heat Transfer Coefficient in the Lost Foam Casting Process

2004 ◽  
Author(s):  
X. J. Liu ◽  
S. H. Bhavnani ◽  
R. A. Overfelt
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Casting Process ◽  
Lost Foam Casting ◽  
Foam Pattern ◽  
Lost Foam ◽  
The Heat Transfer Coefficient ◽  
Zone Temperature

A thermometric technique has been developed to study the thermal characteristics of the foam-metal interaction in the lost foam casting process. A cylindrical foam pattern and heated steel block have been used to estimate the endothermic losses associated with the thermal degradation of the expanded polystyrene at the metal front. Thermocouple readings have been analyzed to determine the temperature of the kinetic zone between the advancing metal front and the receding foam pattern. The heat transfer coefficient between the metal front and the foam pattern has been calculated from the thermal data at the simulated metal front. The results confirmed that the endothermic degradation of the polystyrene pattern at the metal front introduced a steep thermal gradient in the metal and a consistently increasing heat flux. It is found that the heat transfer coefficient, initially 150 W/m2·K increases to 220 ~ 300 W/m2·K during the process. Foam density has marginal effect on the heat flux and heat transfer coefficient, whereas the increase of simulated metal front velocity enhances the heat transfer at the metal front. The kinetic zone temperature is measured to be in the range of 150 to 290°C with an average of 200°C and a gaseous gap size of 1 to 4 cm.

Numerical Modeling of EPS Foam Decomposition in the Lost Foam Casting Process

2005 ◽  
Author(s):  
X. J. Liu ◽  
S. H. Bhavnani ◽  
R. A. Overfelt
Keyword(s):  
Heat Transfer ◽  
Process Parameters ◽  
Experimental Studies ◽  
Casting Process ◽  
Mold Filling ◽  
Lost Foam Casting ◽  
Interfacial Heat Transfer Coefficient ◽  
Filling Process ◽  
Foam Pattern ◽  
Lost Foam

The importance of smooth mold filling in the lost foam casting process has been recognized for a long time. The more uniform the filling process, the better the quality of the casting products that are produced. Successful computer simulations can help reduce the number of trials and cut down the lead time in the design of new casting products by better understanding the complex mechanisms and interplay of different process parameters in the mold filling process. In this study, a computational fluid dynamics (CFD) model has been developed to simulate the fluid flow of molten aluminum and the heat transfer involved at the interfacial gap between the metal and the expanded polystyrene (EPS) foam pattern. The commercial code FLOW-3D was used because it can track the front of the molten metal by a Volume of Fluid (VOF) method and allow complicated parts to be modeled by the Fractional Area/Volume Ratios (FAVOR) method. The code was modified to include the effects of varying interfacial heat transfer coefficient based on gaseous gap pressure which is related to foam degradation and coating permeability. The modification was validated against experimental studies and the comparison showed better agreement than the basic model. Process parameters such as initial metal temperature, foam pattern property, and gating system were investigated. The defect prediction model was also used to study the dependence of defect formation on the process variables.

Influence of Vibration on the Heat Transfer of Lost Foam Casting Filling

2011 ◽  
Vol 418-420 ◽  
pp. 1618-1621 ◽  
Author(s):  
Zhong Zhao ◽  
Zi Tian Fan
Keyword(s):  
Heat Transfer ◽  
Magnesium Alloy ◽  
Molten Metal ◽  
A356 Alloy ◽  
Vibration Energy ◽  
Lost Foam Casting ◽  
Flow Front ◽  
Filling Time ◽  
Lost Foam ◽  
Filling Capacity

The vibration is superimposed to the filling process of aluminum and magnesium alloy in lost foam casting, and the flow lengths and the molten metal temperatures of the flow front are collected, and they compared with no-vibration. The results show that the vibration can significantly improve the filling capacity of the aluminum alloy, magnesium alloy in lost foam casting. Compared to the samples without vibration, the flow lengths of A356 alloy with vibration in lost foam casting increased by 33% and that of AZ91D alloy increased by 15%.The heat transfer of molten metal on the flow front was analyzed, and it indicates that the vibration energy extends the filling time of the molten metal on the flow front in lost foam casting.

Computer Modeling and Experimental Verification of Mold Filling in Counter-Gravity Lost Foam Casting Process

2003 ◽  
Author(s):  
Sayavur I. Bakhtiyarov ◽  
Ruel A. Overfelt
Keyword(s):  
Molten Metal ◽  
Interface Velocity ◽  
Casting Process ◽  
Lost Foam Casting ◽  
Foam Material ◽  
Polymeric Foam ◽  
Gaseous Products ◽  
Velocity Flow ◽  
3D Software ◽  
Lost Foam

A dynamics of the molten metal-polymeric foam interface has been experimentally observed in “window counter-gravity lost foam casting” of standard GM plates. The observations allowed revealing the effect of the pyrolisis of polymeric foam material on molten metal propagation velocity. FLOW-3D software (Flow Science, Inc.) has been used to simulate liquid metal filling dynamics and the molten metal-polymeric foam interface velocity in foam plates. The effect of the degradation gaseous products on the molten metal-polymeric foam interface velocity was taken into consideration through specially written sub-routing program. The results of the simulations are compared with the experimental data obtained in this study.

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