cad
Được đăng lên bởi
Don Do Quy
Số trang: 6 trang

Lượt xem: 985 lần

Lượt tải: 0 lần
Second International Conference on CFD in the Minerals and Process Industries CSIRO, Melbourne, Australia 68 December 1999 SIMULATION OF DIE FILLING IN GRAVITY DIE CASTING USING SPH AND MAGMAsoft 1 1 2 2 Joseph HA , Paul CLEARY , Vladimir ALGUINE and Thang NGUYEN CRC for Alloy and Solidification Technology (CAST) 1 2 CSIRO Mathematical and Information Sciences, Clayton, Victoria 3169, AUSTRALIA CSIRO Manufacturing Science and Technology, Preston, Victoria 3072, AUSTRALIA ABSTRACT This paper reports on the application of smoothed particle hydrodynamics (SPH) and MAGMAsoft to model die filling in gravity die casting and the favourable comparison of SPH simulation results with experiments. The simulation results were able to capture the fine detail of the free surface motion, including plume shape, frequency and phase of oscillation and the correct relative heights of the surface levels at all free surfaces. INTRODUCTION Gravity die casting (GDC) processes are capable of making complicated high integrity components, such as wheels, cylinder heads, engine blocks and brake callipers, at lower cost than most other casting methods. Cycle times for gravity die casting are shorter than for the sand casting process leading to larger quantities of castings produced per unit time. Surface finish and internal quality (particularly pertaining to porosity) are also better using the GDC process. Improvements to both product quality and process productivity can be brought about through improved die design. These include developing more effective control of the die filling and die thermal performance. Numerical simulation offers a powerful and cost effective way to study the effectiveness of different die designs and filling processes. For such simulations to be useful, their accuracy must first be assessed. The validation of numerical simulations is commonly done using water analogue models because of the relative difficulties of visualising the flow of hot molten metal in a die. Nevertheless, the water analogue modelling technique was successfully used to highlight flow features in the die cavity in several die casting processes (Perkins and Bain, 1965, Davis and Asquith, 1985, Nguyen and Ito, 1995). There are a number of available software packages for casting simulation and analysis. These packages are gridbased and employ the volumeoffluid method. In the die casting community, a popular commercial software package for simulating mould filling is MAGMAsoft. S...
Second International Conference on CFD in the Minerals and Process Industries
CSIRO, Melbourne, Australia
68 December 1999
423
SIMULATION OF DIE FILLING IN GRAVITY DIE CASTING
USING SPH AND MAGMAsoft
Joseph HA
1
, Paul CLEARY
1
, Vladimir ALGUINE
2
and Thang NGUYEN
2
CRC for Alloy and Solidification Technology (CAST)
1
CSIRO Mathematical and Information Sciences, Clayton, Victoria 3169, AUSTRALIA
2
CSIRO Manufacturing Science and Technology, Preston, Victoria 3072, AUSTRALIA
ABSTRACT
This paper reports on the application of smoothed particle
hydrodynamics (SPH) and MAGMAsoft to model die
filling in gravity die casting and the favourable
comparison of SPH simulation results with experiments.
The simulation results were able to capture the fine detail
of the free surface motion, including plume shape,
frequency and phase of oscillation and the correct relative
heights of the surface levels at all free surfaces.
INTRODUCTION
Gravity die casting (GDC) processes are capable of
making complicated high integrity components, such as
wheels, cylinder heads, engine blocks and brake callipers,
at lower cost than most other casting methods. Cycle
times for gravity die casting are shorter than for the sand
casting process leading to larger quantities of castings
produced per unit time. Surface finish and internal quality
(particularly pertaining to porosity) are also better using
the GDC process. Improvements to both product quality
and process productivity can be brought about through
improved die design. These include developing more
effective control of the die filling and die thermal
performance.
Numerical simulation offers a powerful and cost effective
way to study the effectiveness of different die designs and
filling processes. For such simulations to be useful, their
accuracy must first be assessed. The validation of
numerical simulations is commonly done using water
analogue models because of the relative difficulties of
visualising the flow of hot molten metal in a die.
Nevertheless, the water analogue modelling technique was
successfully used to highlight flow features in the die
cavity in several die casting processes (Perkins and Bain,
1965, Davis and Asquith, 1985, Nguyen and Ito, 1995).
There are a number of available software packages for
casting simulation and analysis. These packages are grid
based and employ the volumeoffluid method. In the die
casting community, a popular commercial software
package for simulating mould filling is MAGMAsoft.
Smoothed particle hydrodynamics (SPH) is a Lagrangian
method (Monaghan, 1992) and does not require a grid. It
is suited for modelling fluid flows that involve droplet
formation, splashing and complex free surface motion.
Recently, Cleary and Ha (1998), Ha, et al. (1998) and Ha
and Cleary (1999) reported on the application of SPH to
high pressure die casting and the favourable comparisons
of these SPH results with experiments. This paper is
concerned with the application of SPH and MAGMAsoft
to simulate the flow of a single fluid at constant
temperature during gravity die casting. The effects of heat
transfer, solidification and material deformation on GDC
will be the subject of future work.
In this paper, the accuracy of SPH and MAGMAsoft in
meeting our modelling needs in GDC are examined. The
SPH methodology, the MAGMAsoft model and the
experimental setup for GDC are described. These are
followed by the numerical simulation results for two dies
using SPH and MAGMAsoft and their comparisons with
experimental results from the corresponding water
analogue models.
THE SPH METHOD
SPH is a Lagrangian method that uses an interpolation
kernel of compact support to represent any field quantity
in terms of its values at a set of disordered points (the
particles). The fluid is discretised, and the properties of
each of these elements are associated with its centre,
which is then interpreted as a particle. A particle b has
mass
b
m
, position
b
r, density
b
ρ
and velocity
b
v. In
SPH, the interpolated value of any field A at position r is
approximated by:
∑
=
b
b
b
b
b
hW
A
mA ),()( rrr
ρ
(1)
where W is an interpolating kernel, h is the interpolation
length and the value of A at
b
r is denoted by
b
A
. The
sum is over all particles, b with a radius 2h of
b
r . W(r,h)
is a spline based interpolation kernel of radius 2h. It is a
2
C function that approximates the shape of a Gaussian
function and has compact support. This allows smoothed
approximations to the physical properties of the fluid to be
calculated from the particle information. The smoothing
formalism also provides a way to find gradients of fluid
properties. The gradient of the function A is then given
by:
Để xem tài liệu đầy đủ. Xin vui lòng
Đăng nhập
Nếu xem trực tuyến bị lỗi, bạn có thể tải về máy để xem.
cad

Người đăng:
Don Do Quy
5
Tài liệu rất hay!
Được đăng lên bởi
dangthustony

1 giờ trước
Đúng là cái mình đang tìm. Rất hay và bổ ích. Cảm ơn bạn!
6
Vietnamese
cad
9
10
334