Introduction
Simulation input parameters
-
Preform geometry
-
Thermal properties of PET
-
Preform temperature profile
-
Stretch-rod velocity
-
Air flow model
-
Material model
Geometry and idealisation
Material temperature
Material temperature (°C) | Thermal conductivity (W/mK) | Specific heat capacity (J/kgK) | Heat transfer coefficient (cooling) (W/m2K) |
---|---|---|---|
90 | 0.160 | 1601.40 | 9.42 |
115 | 0.143 | 1677.13 | 12.99 |
Oil temperature (°C) | Resultant average preform temperature (°C) | Temperature difference through thickness (°C) |
---|---|---|
95 | 92.6 | 5.98 |
100 | 97.45 | 6.83 |
105 | 101.9 | 7.61 |
110 | 106.46 | 9.16 |
115 | 110.08 | 10.28 |
Air flow rate
Constitutive model for PET
Bond stretching part
| |
Eyring process | |
Shear activation volume V
s,
(m
3
mol
−1
) | 2.814 × 10−3
|
Pressure activation volume V
p,
(m
3
mol
−1
) | 5.262 × 10−4
|
Reference viscosity μ
0
*
, (MPα) | 1.71 |
Limiting temperature T
∞, (K) | 328.76 |
Viscosity constant C
v
, (K) | 67.47 |
Conformational part
| |
Edwards-Vilgis model | |
Inextensibility parameter of entanglement α | 0.1553 |
Looseness parameter of entanglement η
| 0.001 |
Entanglement density N
s,
(m
−3) | 1.81 × 1017
|
Critical network stretch | |
Superposition constant of T
shift
C
1
| −0.0111 |
Superposition constant of T
shift
C
2
| 3.627 |
Superposition constant of T
shift
β
| 0.9856 |
Slope of linear line k
| −0.0356 |
Intercept of linear line b
| 15.393 |
Entanglement slippage viscosity | |
Reference viscosity γ
0
*
, (MPα) | 0.653 |
Limiting temperature T
∞, (K) | 95.48 |
Viscosity constant C
s
, (K) | 10612 |
Superposition constant of T
e
C
1
| 0.157 |
Superposition constant of T
e
C
2
| 39.94 |
Superposition constant of T
e
β
| 0.9878 |
Simulation construction
Simulation validation
Flow index | |||
---|---|---|---|
Oil temperature (°C) | 2 | 4 | 6 |
95 | N2T95 | N4T95 | N6T95 |
100 | N2T100 | N4T100 | N6T100 |
105 | N2T105 | N4T105 | N6T105 |
110 | N2T110 | N4T110 | N6T110 |
115 | N2T115 | N4T115 | N6T1115 |
Cavity pressure
Stretch-rod force
Surface strain rate
Surface strain
True hoop strain | True axial strain | |
---|---|---|
Average | 11.7 % | 12.0 % |
Maximum | 24.3 % (N2T110) | 19.6 % (N2T115) |
Minimum | 0.9 % (N4T105) | 6.8 % (N4T105) |