How can units of heat ever be ft^3/s?

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In summary, the conversation discusses the use of the letter Q to represent both the volumetric throughput rate and the heat transfer rate in a problem. The question arises if this is due to the theory of caloric fluid or simply a coincidence. The conversation concludes with the suspicion that it is the latter and thanks the other person for their help.
  • #1
craveneye13
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Homework Statement
I have a fluid mechanics textbook by Frank White which includes an example problem about a steady flow machine with one inlet and two outlets. The details of the actual problem are actually not so important as the follow: given information includes the areas of the inlets, the heat, the temperature, the pressure, and a height z. Included next to each given quantity is the unit in which its given. Next to heat, the unit is shown as (ft^3/s) where ft is feet and s is seconds. This is confusing me a bit. How can energy have those units? He subsequently even finds the fluid velocity at the inlets by dividing the heat by the inlet area, showing the units were not mistakenly typed. I am rather frustrated. Would anybody be able to explain how energy units would be length cubed over time?
Relevant Equations
Q (ft^3/s), A (ft^2), V (ft/s) => V = Q/A??? Where do the heat units come from??
Please and thank you!
 
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  • #2
Q is the volumetric throughput rate, not heat.
 
  • #3
Chestermiller said:
Q is the volumetric throughput rate, not heat.
Hello, thank you for your response. He does however explicitly refer to dQ/dt as the heat transfer rate in the very same problem. (it is in fact dQ/dt that we are set to find in the problem). Could it be that he is simply equating the volumetric through rate with the heat?
 
  • #4
Chestermiller said:
Q is the volumetric throughput rate, not heat.
Does the use of that same letter for heat flow come from the theory of caloric fluid or did we just run out of alphabet to use?
 
  • #5
craveneye13 said:
Hello, thank you for your response. He does however explicitly refer to dQ/dt as the heat transfer rate in the very same problem. (it is in fact dQ/dt that we are set to find in the problem). Could it be that he is simply equating the volumetric through rate with the heat?
Or I wonder if it is just an unfortunate use of the same letter ha
 
  • #6
hutchphd said:
Does the use of that same letter for heat flow come from the theory of caloric fluid or did we just run out of alphabet to use?
I am beginning to suspect the latter, and I just conflated the two. Thank you for your help!
 
  • #7
craveneye13 said:
Hello, thank you for your response. He does however explicitly refer to dQ/dt as the heat transfer rate in the very same problem. (it is in fact dQ/dt that we are set to find in the problem). Could it be that he is simply equating the volumetric through rate with the heat?
What is the exact word-for-word statement of the problem?
 

Related to How can units of heat ever be ft^3/s?

1. How can units of heat be measured in ft^3/s?

Units of heat can be measured in ft^3/s by using a unit of measurement called BTU (British Thermal Unit). BTU is the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. This unit can be converted to ft^3/s by using the specific heat capacity of a substance and the flow rate of the substance.

2. Why is ft^3/s used as a unit for heat measurement?

Ft^3/s is commonly used as a unit for heat measurement because it is a measure of volume and flow rate. This is useful when measuring the amount of heat being transferred in a system, such as in a heating or cooling system.

3. How is ft^3/s related to the rate of heat transfer?

Ft^3/s is directly related to the rate of heat transfer, as it measures the volume of a substance being transferred per unit of time. This can be used to calculate the amount of heat being transferred in a given system.

4. Can other units be used to measure heat besides ft^3/s?

Yes, there are other units that can be used to measure heat, such as calories, joules, and kilowatt-hours. However, ft^3/s is commonly used in engineering and HVAC systems for its practicality in measuring heat transfer rates.

5. Is ft^3/s the same as cubic feet per second?

Yes, ft^3/s and cubic feet per second are equivalent measurements. They both measure volume per unit of time and can be used interchangeably when measuring heat transfer rates.

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