Finding heat transfer coefficient experimentally

In summary, the conversation discusses the method of finding the heat transfer coefficient through a cubic box by placing objects inside and using the equation Q=h*A*delta-T. The speaker plans to use thermocouples and treat the space in between as a single resistance. They suggest plotting temperature vs. time and taking the derivative to find Q. The speaker also mentions using an enclosed environmental chamber for the project.
  • #1
DinoRF
3
0
I'm working on a project where I have to construct a cubic box, then find the heat transfer coefficient through the box. I will be placing various object in the box to run tests on how they change the eat transfer coefficient. If I want to use the equation: Q=h*A*delta-T, how do I find Q, the heat transfer rate?

I'm thinking I will have thermocouples on the outside surface and on object on the inside of the box. I'll treat all the space in between as a single resistance, since I'm not worried about the heat transfer coefficient with respect to convection, radiation, or conduction, but rather the overall coefficient.

If I got the data for the outside temperature and the inside temperature and plotted that vs. time, would the Q just be the difference divided by the time of that difference?

Once I get Q, then solving for h should be simple.

I've also seen heat flux sensors, but those are expensive and I think and hope they are unnecessary.
 
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  • #2
How are you supplying heat?
 
  • #3
I'm putting the entire system in an enclosed environmental chamber.

I'm just going to plot temp/time and take the derivative to find Q. I'm all set. I'm getting ready to build.
 

Related to Finding heat transfer coefficient experimentally

1. What is the purpose of finding the heat transfer coefficient experimentally?

The purpose of finding the heat transfer coefficient experimentally is to determine the rate of heat transfer between two substances or mediums. This information is crucial for designing and optimizing heat transfer systems.

2. How is the heat transfer coefficient measured in an experiment?

The heat transfer coefficient is typically measured by conducting a controlled experiment in which the temperature difference between two mediums is measured over time. By applying the principles of heat transfer, the heat transfer coefficient can be calculated using the temperature difference, properties of the mediums, and other relevant parameters.

3. What factors can affect the accuracy of heat transfer coefficient measurements?

There are several factors that can affect the accuracy of heat transfer coefficient measurements, including experimental errors, variations in environmental conditions, and assumptions made during calculations. It is important to carefully control and monitor these factors to ensure accurate results.

4. What are the common techniques used for finding the heat transfer coefficient experimentally?

Some common techniques for finding the heat transfer coefficient experimentally include the use of heat flux sensors, thermocouples, and data acquisition systems. Other techniques may involve using heat transfer correlations or performing experiments in controlled laboratory environments.

5. Can the heat transfer coefficient change over time?

Yes, the heat transfer coefficient can change over time due to various factors such as changes in environmental conditions, fouling or buildup on heat transfer surfaces, or changes in the properties of the mediums. It is important to regularly monitor and re-evaluate the heat transfer coefficient to ensure efficient and accurate heat transfer processes.

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