Pressure in a half-full vessel filled with olive oil@330F
Pressure in a half-full vessel filled with olive oil@330F
(OP)
Hello,
we are planning to do some test to see the high temperature performance of a device. To do it, we need to fill an small aluminum tube (ID 2.5", 25" long) with olive oil to about half of its volume, and then put the tube in oven to heat it up to 330 degree fahrenheit. The tube is sealed with oring.
We know the expansion of this oil will about 10%. Olive oil has boiling temp 570F, smoke point 470F. The question is
1. How high the pressure will build up in the tube at 330F?
2. We certainly do not want any smoke (or fire!) since it will ruin the oven (expensive one!). Any issue you see with the plan?
Thanks!
we are planning to do some test to see the high temperature performance of a device. To do it, we need to fill an small aluminum tube (ID 2.5", 25" long) with olive oil to about half of its volume, and then put the tube in oven to heat it up to 330 degree fahrenheit. The tube is sealed with oring.
We know the expansion of this oil will about 10%. Olive oil has boiling temp 570F, smoke point 470F. The question is
1. How high the pressure will build up in the tube at 330F?
2. We certainly do not want any smoke (or fire!) since it will ruin the oven (expensive one!). Any issue you see with the plan?
Thanks!





RE: Pressure in a half-full vessel filled with olive oil@330F
Consider aproximation using a summarion of the 3
Thermal growth change in the cylinder reduces volume
Oil displacement ~10%
Ideal gas law PV=nRT
RE: Pressure in a half-full vessel filled with olive oil@330F
The easiest (if the information is available) answer is - the pressure inside the cylinder will be equal to the vapor pressure of your olive oil @ 330F
RE: Pressure in a half-full vessel filled with olive oil@330F
I'm not immediately understanding AllHandlesTaken claim that the pressure will be the vapor pressure of olive oil at 330F. If olive oil has a boiling point of 570F, the vapor pressure at 330 must be less than 1 atm. Since the other half of the cylinder's volume, I assume, contained air at 1atm when the cylinder was sealed, the pressure would have to increase above 1atm, not decrease.
I would ignore both the thermal expansion of the cylinder and the olive oil's density change and just do ideal gas law on the air. That will get you close enough.
As for #2, I would have a large drop pan isolating any leaks from the heat source.
RE: Pressure in a half-full vessel filled with olive oil@330F
RE: Pressure in a half-full vessel filled with olive oil@330F
According to my calculations just concentrating on the air thats left in the vessel and forgetting that the tube expands for the minute then the pressure of the air at 330F
would be 1.5 times atmospheric ie from the law:-
P1/T1 =P2/T2
desertfox
RE: Pressure in a half-full vessel filled with olive oil@330F
Sorry should have mentioned once you have this pressure you need to check hoop stress in your cylinder as you haven't stated the wall thickness.
desertfox
RE: Pressure in a half-full vessel filled with olive oil@330F
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Pressure in a half-full vessel filled with olive oil@330F
RE: Pressure in a half-full vessel filled with olive oil@330F
**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Pressure in a half-full vessel filled with olive oil@330F
If the oil has never been heated before, it may contain some water. The boiling and smoke pont measurements are short of what you really need, which is the vapor pressure of the fresh oil at 330 F. How much water and how much air are in there will determine the pressure in a cylinder which is heated to final temperature while remaining closed.
RE: Pressure in a half-full vessel filled with olive oil@330F
**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/