Decoding Thermal Measurement Equations with KD2 Pro

In summary, the manual provides the equations used to measure temperature but the user is not sure that they understand them correctly. The equations involve m0, m2, m3, q, and th. Q1 is unclear what "t" stands for, and m0, m2, and m3 are not clear what they represent. Q2 is unclear as to what m0, m2, and m3 are, and q is not clear what it is. Q3 is unclear as to what k is, and th is not clear what it is.
  • #1
carter7gindenv
14
1
Hello, I'm working with a thermal property measurement tool (KD2 pro). The manual provide the equations used to measure temperature but I'm not sure that I understand them correctly.

Temperature during heating (equation 1)
T= m0 + m2t + m3 ln(t)

Temperature during cooling (equation 2)
T= m0 + m2t + m3 ln(t/[t-th])

thermal conductivity (k) (equation 3)
k= q/ (4πm3 )

With (according to the manual)

T = Temperature during heating
m0 = Ambiant temperature during heating
m2 = Rate of background temperature drift
m3 = Slope of a line relating temperature rise to log(°T)
th = Heating time
q = heat per unit length

The probe works by heating up and recording the temperature evolution.

Q1. To begin with, m2*t, what does "t" stands for? Time obviously but as th is already "heating time" I don't really get what it relates to. (never stated in the manual)
Q2. I understand that the real temperature is calculated as the sum of 3 parts. However they elude me.
m0 not sure what temperature it is.
m2 the rate of change in temperature, kinda akin to acceleration but again what is background temperature?
m3 the what?
I also suspect that when the manual says "m2 is the rate of background temperature drift" they are actually referring to m2*t and not just to m2. It would also make more sense because otherwise the 3 parameters are defined with mx but would not refer to the same thing.

Deciphering the parameters would already be a big help to me in understanding the whole formula.

My apologies if the post should be in engineering but I thought that it was more physics than engineering.
I also apologies to people who thought that a '90 progressive rock band named Tool made thermal equation.

Thank you for your priceless help. In the meantime I'll try to contact the manufacturer to have more info.

Additional info : The manual can be viewed here and the equations I'm talking about are 57-58 ( I'm only using a single needle probe ).
 
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  • #3
Thanks for the help. I tried it but it was a bit above my level.
On another article i found that th is actually the time when the heating is turned off.
t seems to be either the amount of time until heating is turned off ( because apparently writing things consistently is for kids... ) or just an amount of time.

Found 2 other article having the exact same wording. *cough* plagiarism
https://www.researchgate.net/publication/261600536_Efficiency_of_the_Needle_Probe_Test_for_Evaluation_of_Thermal_Conductivity_of_Composite_Materials_Two-Scale_Analysis, second
It would not annoy me so much if the wording was clear from the beginning.
Yhea I'm ranting but I'd love a world where scientist would present equations with the same care we ask a high-schooler.

Thank you again for your help.
 

What is the KD2 Pro and how does it work?

The KD2 Pro is a thermal measurement instrument used to measure thermal properties of various materials. It works by using a heat pulse probe to measure the thermal conductivity, thermal diffusivity, and volumetric specific heat capacity of a material.

What are some common applications for the KD2 Pro?

The KD2 Pro is commonly used in industries such as construction, agriculture, and environmental science for measuring the thermal properties of soils, building materials, and other substances. It can also be used in research and development for testing the thermal performance of new materials.

What are the equations used to decode thermal measurements with the KD2 Pro?

The equations used to decode thermal measurements with the KD2 Pro include the transient line source (TLS) method, the heat flow method, and the temperature wave analysis (TWA) method. These equations are used to calculate the thermal conductivity, thermal diffusivity, and volumetric specific heat capacity of a material.

What factors can affect the accuracy of thermal measurements with the KD2 Pro?

There are several factors that can affect the accuracy of thermal measurements with the KD2 Pro, including the placement and orientation of the heat pulse probe, the moisture content and density of the material being tested, and any external heat sources or temperature gradients. It is important to follow proper procedures and calibrate the instrument regularly to ensure accurate measurements.

Are there any limitations to using the KD2 Pro for thermal measurements?

While the KD2 Pro is a highly accurate and versatile instrument, there are some limitations to consider. It is not suitable for measuring thermal properties of materials with high thermal conductivity or low thermal diffusivity, such as metals. Additionally, the heat pulse probe may not be able to penetrate certain types of materials, making it difficult to obtain accurate measurements.

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