scholarly journals Lumped-Capacity Method for Easy Estimation of Interfacial Heat Transfer Coefficients in Die Casting

2020 ◽  
Vol 8 (3) ◽  
pp. 104-108
Author(s):  
Zehui Sun ◽  
◽  
Guoli Li ◽  
Zhe Qian ◽  
Weifei Li ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Die Casting ◽  
Interfacial Heat Transfer ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Capacity Method

Determination of Heat Transfer Coefficients Using a 1-D Flow Model Applied to Irregular Shaped Cooling Channels in Pressure Diecasting

1999 ◽  
Vol 122 (4) ◽  
pp. 678-690 ◽  
Author(s):  
L. D. Clark ◽  
K. Davey ◽  
I. Rosindale ◽  
S. Hinduja
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Flow Model ◽  
Die Casting ◽  
Casting Machine ◽  
Transfer Coefficients ◽  
Element Mesh ◽  
Cooling Channels ◽  
Heat Transfer Coefficients ◽  
Effective Heat

A mesh partitioning strategy is presented which facilitates the application of boundary conditions to irregular shaped cooling channels in the pressure diecasting process. The strategy is used to partition a boundary element mesh, but can also be applied to the surface of a cooling channel bounded by a finite element mesh. The partitioning of the mesh into a series of element packs enables a one-dimensional flow model to be applied to the coolant. The flow model is used in conjunction with a steady-state thermal model which initially assumes that no boiling is taking place on the die/coolant interface. Values of bulk temperature, pressure, and velocity in the coolant are thus ascertained. This information, together with die temperatures, is then used in empirical relationships which model the various heat transfer mechanisms, including nucleate and transitional film boiling, between die and coolant. Effective heat transfer coefficients are calculated and applied at the die/coolant interface. The steady-state thermal code and the empirical boiling model are then used iteratively until stable values for the effective heat transfer coefficients are obtained. The models are tested by casting a small thin component using a die with conventional cooling channels and also using a novel die with irregular shaped cooling channels running on a hot chamber proprietary die casting machine. Simulation results are shown and experimental results using the hot chamber pressure die casting machine are reported. [S1087-1357(00)02302-9]

Experimental study on interfacial heat-transfer coefficients at the casting/die interface in squeeze casting under transient condition

2018 ◽  
Vol 41 (7) ◽  
pp. 802-807
Author(s):  
A. P. Venkatesh ◽  
K. Logesh ◽  
Sirigireddy. Manjith Kumar Reddy ◽  
Omer Ahmed Khan ◽  
Syed Sadiq Ur Rehman ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Squeeze Casting ◽  
Transient Condition ◽  
Interfacial Heat Transfer ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

Optimization for boiling heat transfer determination and enhancement in pressure die casting

2002 ◽  
Vol 216 (12) ◽  
pp. 1589-1609
Author(s):  
K Davey ◽  
S Hinduja ◽  
L D Clark
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Die Casting ◽  
Casting Process ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Non Linear ◽  
Die Casting Process ◽  
Channel Configuration ◽  
Pressure Die Casting

Boiling in cooling channels has recently been demonstrated to be an effective mechanism for heat extraction in pressure die casting. Boiling heat transfer can be enhanced by cooling channel shape optimization. The occurrence of boiling presents a non-linear thermal problem which, when combined with shape optimization, necessitates the solving of non-linear equations for each channel configuration. In this paper a methodology is presented that involves the use of optimization for the combined determination of channel shapes and heat transfer coefficients. It is shown in the paper how this approach results in the accurate determination of boiling heat transfer coefficients on the final optimized cooling channel configuration. The non-linear thermal problem is calculated at very little computational cost over that required for a comparable linear problem. Focus in the paper is on the application of the methodology to the pressure die casting process. The approach adopted is founded on a design sensitivity analysis using the material derivative adjoint variable method. The thermal model for the pressure die casting process is founded on the boundary element method and the optimization is performed using a conjugate gradient scheme. Geometrical constraints are enforced using buffer elements superimposed on to the boundary element mesh. Numerical and experimental trials are performed to demonstrate the potential of the new optimization methodology.

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