Heat Transfer Aspects of Nonisothermal Axisymmetric Upset Forging

1984 ◽  
Vol 106 (3) ◽  
pp. 187-195 ◽  
Author(s):  
P. Dadras ◽  
W. R. Wells
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Finite Difference ◽  
Transfer Process ◽  
Heat Transfer Process ◽  
Physical Characteristics ◽  
Transient Heat Transfer ◽  
Interfacial Film ◽  
Upset Forging ◽  
Finite Difference Solution

A finite difference solution for the transient heat transfer during axisymmetric upset forging has been developed. The interfacial film between the die and the billet has been included in the analysis, and all modes of heat transfer have been taken into account. The results of a parallel experimental study have also been presented. The effects of geometrical and physical characteristics of the billet and the die on the heat transfer process, particularly on die heating, have been systematically investigated.

Transient Heat Transfer of Piston/Rings/Liner System in Diesel Engines

2005 ◽  
Author(s):  
Daxi Xiong ◽  
Tian Tian ◽  
Victor Wong
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Transfer Process ◽  
Diesel Engines ◽  
Frictional Heating ◽  
Heat Transfer Process ◽  
Transient Heat Transfer ◽  
Transient Temperature ◽  
Piston Rings ◽  
Liner System

In diesel engines, transient heat transfer in the piston/rings/liner system greatly affects the performance of the engine, such as in carbon deposit buildup, microwelding, lubricant degradation, and changing mechanical properties of the materials. The current work aims at studying the local piston/rings/liner transient heat-transfer process by incorporating real time dynamics of the rings in sufficient detail. In the present study, several techniques have been adopted to simulate the transient heat transfer process, with fully-incorporated ring dynamics. These techniques include using the model/submodel approach, local refined mesh approach, and the virtual thermal conductivity approach. The transient temperature and heat flux profiles in the piston and rings are illustrated. The results show that the relative movement of the rings greatly affects the temperature/heat flux distribution and the peak temperature in the top ring. The friction heating between the top ring and the liner is also evaluated. The analysis demonstrates that under some extreme conditions when frictional heating reaches its peak value, some heat flux directs back to enter the ring.

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