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time it takes to freeze 500 ml or an 18.5 L water jug
Posted 2011年1月24日 GMT-5 21:22 Heat Transfer & Phase Change 2 Replies
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My water bottles in the garage are starting to freeze, some of them any way. As I looked at them wondering I did an experiment by placing a 500 ml water bottle 6 cm in diameter outside, the temp was -12 C. It took 2 hrs 45 min to freeze fully. Then I thought maybe I could do that simulation in comsol and estimate the time it takes, how about a full 18.5 L jug at 26 cm diameter....quick search here and I did not find any in the log, any ideas on how to go about doing this fruitfully.
Thanks.
Thanks.
2 Replies Last Post 2011年1月25日 GMT-5 09:38
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Posted:
1 decade ago
Hi Kamal,
the tricky part is probably the phase transition of water. You need to find something like effective heat capacity, taking the melting enthalpy into account. And you need thermal conductivity of water and ice and define it all as a function of temperature.
For a first test you might ignore convection and radiation and just define a moderately cold outside boundary of the bottle. If you want to include convection, keep the anomal density behavior of water around 4°C in mind.
I was doing something similar with the melting of polymers years ago. There was an example about continuous casting of aluminum that helped a lot. I think it was in the 3.1 version, maybe it is still there in the newer versions.
Well, similar issue here in northern Germany: the rain water tank freezes if I don't pay attention. So let us know how it progresses.
Best regards
Edgar
the tricky part is probably the phase transition of water. You need to find something like effective heat capacity, taking the melting enthalpy into account. And you need thermal conductivity of water and ice and define it all as a function of temperature.
For a first test you might ignore convection and radiation and just define a moderately cold outside boundary of the bottle. If you want to include convection, keep the anomal density behavior of water around 4°C in mind.
I was doing something similar with the melting of polymers years ago. There was an example about continuous casting of aluminum that helped a lot. I think it was in the 3.1 version, maybe it is still there in the newer versions.
Well, similar issue here in northern Germany: the rain water tank freezes if I don't pay attention. So let us know how it progresses.
Best regards
Edgar
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Posted:
1 decade ago
If you are able to handle phase transition (maybe by using new physics: chemical reaction - phase fraction variable), you may obtain usable results. But at least, it should be necessary to take the undercooled liquid into account - non-moving water can be easily undercooled!?