Influence of Forced Convection on the Solidification of Metal in Cast-Iron and Ceramic Ingot Molds

Conventionally, the study of convection heat transfer merely focuses on the behavior of air flow without considering the conductive effect of the horizontal flat plate. However, it is expected that the conductive effect of the horizontal plate somewhat affects the air flow temperature across the flat plate. Therefore, it is motivated to study the variation of air flow temperature across different materials of flat plate in various time frame. The materials used in this study are aluminium, stainless steel and cast iron. Infrared camera and FloEFD simulation software are used to measure the upper surface temperature of the flat plate. For forced convection, the study is carried out within the range of 103 £ Re £ 104 and within the range of 1 × 107 £ Ra < 2.2 × 107 for natural convection. Flow velocity of 2.3 m/s, 4.1 m/s and 5.2 m/s are used for the forced convection. The results showed that aluminium plate cools down faster than the other two metal plates used in all scenarios. Stainless steel’s temperature goes down faster compared to cast iron. These results were supported by the fact that aluminium has higher heat transfer rate of other metals. For forced convection, the discrepancies of temperatures between experimental and simulation studies are below 10%, which demonstrates that the results are reasonably acceptable. For natural convection, even though the discrepancies between simulation and experimental results on temperature variations are relatively large, the temperatures varied in similar pattern. This indicates that the results are reliable.

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Enhancement of Coolant Side Heat Transfer in Water Cooled Engines by Using Finned Cylinder Heads

ASME 2005 Internal Combustion Engine Division Fall Technical Conference (ICEF2005) ◽

10.1115/icef2005-1320 ◽

2005 ◽

Cited By ~ 2

Author(s):

Mohamed Y. E. Selim ◽

S. M. S. Elfeky ◽

A. Helali

Keyword(s):

Heat Transfer ◽

Cast Iron ◽

Flow Velocity ◽

Forced Convection ◽

Cylinder Head ◽

Cast Steel ◽

Bulk Temperature ◽

Subcooled Boiling ◽

Iron Specimen ◽

Fin Length

An experimental investigation has been carried out for almost the first time to examine the heat transfer by forced convection and subcooled boiling from a finned water-cooled engine cylinder head using steady state technique. Cast iron and cast steel specimens with and without fins have been used in the present work. The effects of flow velocity, coolant bulk temperature, fin length, fin number and fin material have been examined. It has been found that the use of finned cylinder head surface greatly improves the forced convection heat transfer coefficient and subcooled boiling heat flux as the fin length and number influenced the heat transfer process. The cast iron specimen exhibited better heat transfer characteristics over the cast steel one. The effects of bulk flow velocity and temperature for flat and finned specimens have been evaluated for forced convection and subcooled boiling. A correlation has been developed to relate the Nusselt number with Reynolds’ number, Prandtl number, viscosity ratio and fin length ratio, for forced convection from the cast iron specimen, which read: Nu=0.023Re0.697Pr0.33μr0.14(1+A)0.623

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