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Hi all,
I have a unique problem that I need some direction on. I have a .5x.5x.75 meter adiabatic chamber. No heat loss from chamber walls to the atmosphere.
Inside the chamber there is an electrical flat heater plate .5x.05 meter with constant 100W. A fan blows air over the heater bar at 0.25 kg/s (V =3m/s).
The air temp in the chamber rises from 20°C to a controlled 40°C. It never goes over 40° and it takes 60 minutes to reach a temp of 40° from 20°.
Inside this chamber is a 2L soda bottle. How long would it take to warm up the soda bottle to a temp of 40°C from 20°? The bottle is placed in the middle of the chamber not touching the chamber ( no Conduction).
I need to graph Temp vs. time of the soda bottle.
I am having problems with a lot of aspects:
-First the heat transfer from the heater bar to the air is difficult to do because the air temp is constantly rising. My forced convection over a plate calculations don’t make for a constant convection coefficient this way.
-The air volume in the chamber is constant, but a lot of heat transfer problems I have come across don’t account for this. They account for the heater bar volume and the time it takes to cool off, but my heater bar is a constant 100W output.
-How can I relate the air heat transfer from the heater bar to the soda bottle? The soda bottle will take longer to heat up than the air inside the chamber.
The problems sounds easier than it is, but there are a lot of things to consider. I would appreciate any information .
I have a unique problem that I need some direction on. I have a .5x.5x.75 meter adiabatic chamber. No heat loss from chamber walls to the atmosphere.
Inside the chamber there is an electrical flat heater plate .5x.05 meter with constant 100W. A fan blows air over the heater bar at 0.25 kg/s (V =3m/s).
The air temp in the chamber rises from 20°C to a controlled 40°C. It never goes over 40° and it takes 60 minutes to reach a temp of 40° from 20°.
Inside this chamber is a 2L soda bottle. How long would it take to warm up the soda bottle to a temp of 40°C from 20°? The bottle is placed in the middle of the chamber not touching the chamber ( no Conduction).
I need to graph Temp vs. time of the soda bottle.
I am having problems with a lot of aspects:
-First the heat transfer from the heater bar to the air is difficult to do because the air temp is constantly rising. My forced convection over a plate calculations don’t make for a constant convection coefficient this way.
-The air volume in the chamber is constant, but a lot of heat transfer problems I have come across don’t account for this. They account for the heater bar volume and the time it takes to cool off, but my heater bar is a constant 100W output.
-How can I relate the air heat transfer from the heater bar to the soda bottle? The soda bottle will take longer to heat up than the air inside the chamber.
The problems sounds easier than it is, but there are a lot of things to consider. I would appreciate any information .
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