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Heat capacity unit error - ODE function

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Heat capacity unit error - ODE function

Hello everyone,

This is my first time ever using MathCAD. I have no ideas but watching some video help me to create this sheet. I got the error unit of Cp (heat capacity) = BTU/lb*F. MathCAD error is value should be scalar or matrix.

 

I also set up the ODE function. Would you please help me to take a look this and guide me where I was wrong?

 

Thank you so much for your help. I attached the file in this post

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1 ACCEPTED SOLUTION

Accepted Solutions
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Re: Heat capacity unit error - ODE function

As Valery pointed out you used F (Farad) instead of °F (Degree Fahrenheit).

Furthermore you have to be aware, the working with temperatures can be quite tricky! Prime converts all temperature values to K (Kelvin) and does the calculations in K. Because the conversion between K and °F is not homogenous (its not a simple factor) this quickly can create confusion and this is the reason why Prime offers °F AND Delta°F. Look at the picture below.

Werner_E_0-1602938062194.png

Another error in your sheet is that in the solve block you wrote the IC in two separate regions (one with "T(0 min)" and the other with "..=120°F".

 

Hope the attached sheet helps. Instead of "Delta°F" you may also use "R" (Rankine) as Valery had suggested.

View solution in original post

4 REPLIES 4
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Re: Heat capacity unit error - ODE function

Farada.png

Re: Heat capacity unit error - ODE function

Thank you so much! I really appreciated your help. Thank you so much again

Highlighted

Re: Heat capacity unit error - ODE function

As Valery pointed out you used F (Farad) instead of °F (Degree Fahrenheit).

Furthermore you have to be aware, the working with temperatures can be quite tricky! Prime converts all temperature values to K (Kelvin) and does the calculations in K. Because the conversion between K and °F is not homogenous (its not a simple factor) this quickly can create confusion and this is the reason why Prime offers °F AND Delta°F. Look at the picture below.

Werner_E_0-1602938062194.png

Another error in your sheet is that in the solve block you wrote the IC in two separate regions (one with "T(0 min)" and the other with "..=120°F".

 

Hope the attached sheet helps. Instead of "Delta°F" you may also use "R" (Rankine) as Valery had suggested.

View solution in original post

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Re: Heat capacity unit error - ODE function

Thank you so much for the attached file. I have better ideas. Have a good day!

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