- #1
nickelous
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Hi all. I'm doing a heat and mass transfer whereby I'm supposed to come up with a relevant daily life example and do a 2 pg report on it. I have kind of decided to do on popcorn popping via convection.
So basically from my web research the popcorn kernel contains about 13% moisture and the rest being starch granules. One of the popping mechanism I read states that at a pressure of 8 atm, the pressure that is building up inside the kernel by the superheated water at 448K would be too much for the pericarp, thus causing it to break apart. The superheated water would then turn into steam with the release of pressure and expand 1500 times its original volume as water. Thereafter, the starch granule expand and blow up thus forming the popcorn we know.
I have thought of modelling the popcorn kernel as a spherical tank in a unsteady state heat transfer into the water contained in this 'spherical tank'. Thereafter I can calculate the time required for the water to reach 448K. The heat transfer coefficient for sphere is as such
Now the problem is I do not really know how to begin :/ The water does not occupy the entire volume of the tank (as there is starch as well). In addition, I'm not too sure how to take the thermal resisitivty of the pericarp into account. As such I would really appreciate if someone can give some kind guidance!
So basically from my web research the popcorn kernel contains about 13% moisture and the rest being starch granules. One of the popping mechanism I read states that at a pressure of 8 atm, the pressure that is building up inside the kernel by the superheated water at 448K would be too much for the pericarp, thus causing it to break apart. The superheated water would then turn into steam with the release of pressure and expand 1500 times its original volume as water. Thereafter, the starch granule expand and blow up thus forming the popcorn we know.
I have thought of modelling the popcorn kernel as a spherical tank in a unsteady state heat transfer into the water contained in this 'spherical tank'. Thereafter I can calculate the time required for the water to reach 448K. The heat transfer coefficient for sphere is as such
Now the problem is I do not really know how to begin :/ The water does not occupy the entire volume of the tank (as there is starch as well). In addition, I'm not too sure how to take the thermal resisitivty of the pericarp into account. As such I would really appreciate if someone can give some kind guidance!