The Pizza Pouch Project

1
The Pizza Pouch Project

• Joonshick Hwang
• Brian Pickup
• Winter 2007 ME 340 Final Project

2
Objective

• Analyze how an insulated delivery pizza pouch
  maintains proper pizza temperature
• Determine the difference in old method delivery
  to new
• Create equation to estimate the time it took for
  the delivery boy to get to your door

3
Analytical Procedure

• Set up system using approximate transient
  analysis
• Assume convective coefficients and approximate 3M
  Thinsulate material properties
• Test Fo number
• Graph results

Approximate Analysis
4
Experimental Set Up

• Get pizzas and delivery pouch from Pizza Hut
• Obtain thermocouples, temperature meter, and
  calipers
• Record temperatures inside the boxes and inside
  the pizza pouch at 10 minute intervals
• Graph experiment results
• Eat the pizzas

5
Assumptions

• Transient state (not steady state)
• Convective coefficients are estimates
• Temperature distribution of walls is closely
  related to temperature distribution of air inside
• Free convection
• Constant ambient temperature (taken as an
  average)

6
Material Properties
Cardboard
3M Thinsulate
TOO BIG for lumped capacitance
Bi .2
Bi .6
7
Results
8
Results
9
Results
10
Discussion

• Delivery pouch maintained high temperature much
  better than the pizza box
• Approximate transient analysis accurate in
  simulating heat loss of pizza
• Analysis for pouch gave higher values than
  experiment because the pouch had openings
• Convective coefficients vary due to
• Movement of the pizza boxes
• Environmental factors
• Number of pizza boxes and size of delivery pouch
  change temperature distribution

11
How long has it been?
Time is given in minutes
12
Conclusion

• Fo gt .2 , ok!
• Approximate transient analysis could be used to
  estimate the time of delivery of pizza
• Always use the insulating pouch to keep the pizza
  hot
• 30 minutes is the most you want to wait for your
  pizza, even with the pouch