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heat object with fluid
- Thread starter ymehdi
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Specific heat? Thermal conductivity? Size?
Ignoring all of that; temperature rise is asymptotic to oil temperature, so near infinite time to reach.
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Ignoring all of that; temperature rise is asymptotic to oil temperature, so near infinite time to reach.
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- Thread starter
- #3
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- #5
This is your experiment, how can you not know the properties?
lumped capacitance method
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lumped capacitance method
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What are the properties of the oil?
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You should ask your instructor; the equations change, depending on the properties.
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- #9
its independent i cant ask them.
the oil im using is shell heat transfer oil s2
the data for it is here:
the metal im using is carbon steel and they say thermal conductivity is around 45 watts per kelvin per meter
and thank you for helping
the oil im using is shell heat transfer oil s2
the data for it is here:
the metal im using is carbon steel and they say thermal conductivity is around 45 watts per kelvin per meter
and thank you for helping
Did you even look at the link I posted?
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LittleInch
Petroleum
yhemdi,
This is a transient simulation and hence is ill suited to a calculation, though the paper linked to by IR stuff has a good try.
However depending on how accurate you need to be you can work on some assumptions.
The metal will need a certain amount of heat energy to go from 50 to 100C
This heat energy is supplied by the oil, but at an unknown rate.
What do you mean by "full contact?"
Your unknowns:
How much heat is lost by the outside of your block to air / other losses. Again a temperature dependant thing as the hotter it gets the greater the losses.
Unless this block is heavily insulated
Heat transfer rate and oil flow. You say nothing about oil flow rate. It has be be big enough that it's exit temperature is close to the inlet temperature for simple calculations to work.
So work or estimate some of those and you might get close.
As said if the oil temp is 100 and your target temp is a 100 you will get to 97 or98 but to get to 100 will take a loooooong time. Maybe better to have at least 10C difference between oil temp and desired block temperature
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
This is a transient simulation and hence is ill suited to a calculation, though the paper linked to by IR stuff has a good try.
However depending on how accurate you need to be you can work on some assumptions.
The metal will need a certain amount of heat energy to go from 50 to 100C
This heat energy is supplied by the oil, but at an unknown rate.
What do you mean by "full contact?"
Your unknowns:
How much heat is lost by the outside of your block to air / other losses. Again a temperature dependant thing as the hotter it gets the greater the losses.
Unless this block is heavily insulated
Heat transfer rate and oil flow. You say nothing about oil flow rate. It has be be big enough that it's exit temperature is close to the inlet temperature for simple calculations to work.
So work or estimate some of those and you might get close.
As said if the oil temp is 100 and your target temp is a 100 you will get to 97 or98 but to get to 100 will take a loooooong time. Maybe better to have at least 10C difference between oil temp and desired block temperature
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
Oh, from your other posts, I thought the object was immersed in the oil, not that the oil is flowing through it, presumably, like coolant in an engine.
So, yes, if there's ANY loss of heat to the ambient or elsewhere, you will never reach 100C everywhere in your "object"
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So, yes, if there's ANY loss of heat to the ambient or elsewhere, you will never reach 100C everywhere in your "object"
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I also thought that the object is immersed in oil. Lumped capacitance method can be used for pipe (cylinder) with oil flowing inside (this example is even solved in aforementioned book). However, I'm afraid that for a block it will be much more difficult (if at all possible). Thus I would use numerical simulation to solve this problem.
- Thread starter
- #14
Ok
for this experiment we will be calculating with no loss
and depending on the temperature of the oil it can flow around 49-47 L/min
its acts as radiator as you say fluid goes in circulates around and then goes out however its a solid block not just tubing and fins
if the oil flowing at 110 degrees ( we dont count the time for oil to heat up to temp) and is flowing in the metal block can we not use temp of oil and just the mass of the object to work out time to heat up or can we not do this as its a fluid heat up a solid and not a solid heating up another solid?
thank you for everyone help i appreciate it
for this experiment we will be calculating with no loss
and depending on the temperature of the oil it can flow around 49-47 L/min
its acts as radiator as you say fluid goes in circulates around and then goes out however its a solid block not just tubing and fins
if the oil flowing at 110 degrees ( we dont count the time for oil to heat up to temp) and is flowing in the metal block can we not use temp of oil and just the mass of the object to work out time to heat up or can we not do this as its a fluid heat up a solid and not a solid heating up another solid?
thank you for everyone help i appreciate it
So, I don't get this task that you volunteered to do, with, seemingly, no coursework in heat transfer, and, seemingly, the lack of desire to crank through your own resources, or the links we've provided.
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I have not read all the posts so I am assuming that the oil temperature remains the same when the object is immersed in the oil bath. To keep the oil at a constant temperature, a heating source is required so you should then know the value of the heat input to the oil bath. the amount of heat absorbed by the block will then be equal to the heat input to the oil bath and we are discounting all heat losses to the environment. So far for equation, we have:
Qin= M*Cp*dT/Dt; Qin (but/hr),M (lbm of block), Cp (Btu/(Lbm-dF),dT/dt (rate of rise the object temperature in degrees F/time element be it sec,min,hr)
All units are in the English system and it's up to you to convert into the Metric units. The equation that I presented is emendable to a spread sheet. You could also use integration for a solution. I would use both as a mean to determine accuracy.
Qin= M*Cp*dT/Dt; Qin (but/hr),M (lbm of block), Cp (Btu/(Lbm-dF),dT/dt (rate of rise the object temperature in degrees F/time element be it sec,min,hr)
All units are in the English system and it's up to you to convert into the Metric units. The equation that I presented is emendable to a spread sheet. You could also use integration for a solution. I would use both as a mean to determine accuracy.
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