The effect of strontium modification on casting/chill interfacial heat flux and casting surface profile during solidification of Al-7Si alloy

2013 ◽  
Author(s):  
V. Vijeesh ◽  
K.N. Prabhu
Keyword(s):  
Heat Flux ◽  
Surface Profile ◽  
Casting Surface ◽  
Interfacial Heat Flux

On penetrative convection at low Péclet number

1995 ◽  
Vol 292 ◽  
pp. 229-248 ◽  
Author(s):  
John R. Lister
Keyword(s):  
Heat Flux ◽  
Fluid Layer ◽  
Diffusion Problem ◽  
Stable Region ◽  
Base Temperature ◽  
Linear Temperature ◽  
Linear Temperature Gradient ◽  
Wide Range ◽  
Fixed Base ◽  
Interfacial Heat Flux

A new theoretical model is developed for the growth of a convecting fluid layer at the base of a stable, thermally stratified layer when heated from below. The imposed convective heat flux is taken to be comparable to the heat flux conducted down the background gradient so that diffusion ahead of the interface between the convecting and stable layers makes a significant contribution to the interfacial heat flux and to the rate of rise of the interface. Closure of the diffusion problem in the stable region requires the interfacial heat flux to be specified, and it is argued that this is determined by the ability of convective eddies to mix warmed fluid below the interface downwards. The interfacial velocity, which may be positive or negative, is then determined by the joint requirements of continuity of heat flux and temperature. A similarity solution is derived for the case of an initially linear temperature gradient and uniform heating. Solutions are also given for a heat flux that undergoes a step change and for a heat flux determined from a four-thirds power law with a fixed base temperature. Numerical calculations show that the predictions of the model are in good agreement with previously reported experimental measurements. Similar calculations are applicable to a wide range of geophysical problems in which the tendency for diffusive restratification is comparable to that for mixed-layer deepening by entrainment.

scholarly journals Experimental Study of Interfacial Heat Flux and Surface Temperature by Inverse Analysis with Thermocouple (Fully Embedded) during Hot Steel Strip Rolling

2012 ◽  
Vol 452-453 ◽  
pp. 959-963 ◽  
Author(s):  
Daniel Weisz-Patrault ◽  
Alain Ehrlacher ◽  
Nicolas Legrand ◽  
Nathalie Labbe ◽  
Jaroslav Horský ◽  
...  
Keyword(s):  
Heat Flux ◽  
Surface Temperature ◽  
Steel Strip ◽  
Theoretical Models ◽  
Calibration Procedure ◽  
Rolling Process ◽  
Fundamental Aspect ◽  
Strip Rolling ◽  
Interfacial Heat Flux ◽  
Good Agreement

Knowledge of temperature distribution in the roll is fundamental aspect in cold rolling. An inverse analytical method has been previously developed to determine interfacial heat flux and surface temperature by measuring the temperature with a thermocouple (fully embedded) at only one point inside the roll. On this basis some pilot mill tests have been performed. The temperature sensor, the calibration procedure and rolling tests at different strip rolling conditions (5%, 10%, 15% and 20%) are described. Results show a good agreement with well-known theoretical models. Moreover the CPU times of the method (around 0.05 s by cycle) enable an online control of the rolling process.

scholarly journals Experimental Study of Interfacial Heat Flux and Surface Temperature by Inverse Analysis with Thermocouple (Fully Embedded) during Hot Steel Strip Rolling

2012 ◽  
Vol 452-453 ◽  
pp. 959-963 ◽  
Author(s):  
Daniel Weisz-Patrault ◽  
Alain Ehrlacher ◽  
Nicolas Legrand ◽  
Nathalie Labbe ◽  
Jaroslav Horsky ◽  
...  
Keyword(s):  
Experimental Study ◽  
Heat Flux ◽  
Surface Temperature ◽  
Inverse Analysis ◽  
Steel Strip ◽  
Strip Rolling ◽  
Interfacial Heat Flux

Aluminum Sand Casting Interfacial Heat Flux Estimation Based on Corrected Temperature Measurements

2008 ◽  
Author(s):  
Jonathan W. Woolley ◽  
Keith A. Woodbury
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Conduction ◽  
Kernel Method ◽  
Heat Conduction Problem ◽  
Inverse Heat Conduction Problem ◽  
Temperature Measurements ◽  
Inverse Heat Conduction ◽  
Interfacial Heat Transfer ◽  
Interfacial Heat Flux

The estimation of the heat flux at the interface between a solidifying metal casting and mold is a frequently investigated topic. Accurate knowledge of the interfacial heat transfer can be used in solidification simulation to reduce the time and cost of the casting design process. A common and well-established approach to estimating the interfacial heat flux is the solution of the inverse heat conduction problem. Temperature measurements from thermocouples imbedded in the sand mold are used as inputs to the inverse solver. It is well-documented that imbedded thermocouples which are subjected to high temperature gradients will yield biased temperature measurements. By accounting for the sensor dynamics with an appropriate model, the measured temperatures can be corrected to mitigate the effect of the bias error in the estimation of the heat flux. In a previous work, experimentally measured temperatures were obtained from aluminum sand castings and the interfacial heat transfer was evaluated. In other works, the temperature measurement error was demonstrated and the kernel method for correcting measured temperatures was demonstrated with a numerical experiment. In this paper, the simulation of the response of a thermocouple with a three-dimensional computational model is used with the kernel method to correct the experimentally measured temperatures. The previous interfacial heat flux estimates are updated by solving the inverse heat conduction problem with the corrected temperatures as the inputs.

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