Feature
Validation of the Thermal
Modeling Process for
Cold-Chain Shippers
One company shows a strong parallel between phase change simulations and
actual data.
By Richard M. Formato, Cold Chain Technologies Inc. and Iftekhar Ahmed, Maya HTT Ltd.
In “Bringing Cold Chain Shippers to
Market Faster with Thermal Modeling” (Pharmaceutical & Medical Packaging News, May 2008), we discussed
Cold Chain Technologies’ (CCT)
use of predictive thermal modeling
to simulate multiple design scenarios
to arrive at an optimal configuration
before making prototypes and conducting chamber testing. A computer program used during the modeling process
lets the user pass through a number of
required steps, including analysis selection, geometry creation, element selection, boundary condition application,
and program execution.
As this modeling process makes certain approximations and assumptions,
model validation must occur before
the process can be confidently utilized
over CCT’s full array of products. This
article discusses the thermal modeling
validation process that is being under-taken by CCT to accomplish this task,
along with some of its initial results.
Phase Change Experimental Setup
Brick #1
Brick #2
Each Brick Measures
Length: 7”
Width: 5”
Thickness: 1”
Top
Midpoint C
Gravity
Absolute
B
Center
THERMAL MODELING
VALIDATION METHOD
To successfully simulate thermal
packaging, modeling (and validation) of
the complete transient thermal response
must be completed. This validation
process includes, but is not limited to,
the following coupled areas:
• Phase change of refrigerant
(transient).
Bottom
A
MJ
Figure 1: 316F Foam Brick (back to back) Phase Change Experimental Setup. In this experiment, two CCT
water-based foam bricks (CCT 316F, 7 × 5 × 1 in.) were placed back-to-back with three TCs.
• Free convection in shipper (transient).
• Conduction in shipper (transient).
• Payload geometry approximations.
•Material properties of shipper
components.
By validating each of the above areas
separately, the complete thermal package can be simulated with much more
certainty. In general, the validation
process consists of the following steps:
