- #1
arehman1289
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Hello,
I am a student in Coventry, UK working on Phase Change Problems and going through 1-Phase Neumann Analytical solutions.
As per most books, or specifically Mathematical Modeling of Melting and Freezing Processes chapter 2 (attached) page 36, equation 15, the general equation of temperature distribution, after solving parabolic differential equations is given?
http://www.math.utk.edu/~vasili/475/Handouts/4.PhChgbk.2.1.pdfFollowing are the attached graphs from the book and the plot I get from matlab, with the following values .
lambda = 0. 3777
alpha l = 1. 347 ´10-3
x = 1 cm
tl = 25 degrees
delta tl = 25 degrees
The problem lies in the initial value of temperature. I always get it in negative although the initial temperature is 0 degrees. If you look at the equation 15 (from the link) for time = 0, the denominator is always (erf(0.377) 0.41 while the numerator is 1 giving the temperature answer in negative. hence i thought it is a printing error or any other logical explanation ? Is it something to do with the error functions ?
I would really really appreciate your response.
Thanks & Regards
Abdur
I am a student in Coventry, UK working on Phase Change Problems and going through 1-Phase Neumann Analytical solutions.
As per most books, or specifically Mathematical Modeling of Melting and Freezing Processes chapter 2 (attached) page 36, equation 15, the general equation of temperature distribution, after solving parabolic differential equations is given?
http://www.math.utk.edu/~vasili/475/Handouts/4.PhChgbk.2.1.pdfFollowing are the attached graphs from the book and the plot I get from matlab, with the following values .
lambda = 0. 3777
alpha l = 1. 347 ´10-3
x = 1 cm
tl = 25 degrees
delta tl = 25 degrees
The problem lies in the initial value of temperature. I always get it in negative although the initial temperature is 0 degrees. If you look at the equation 15 (from the link) for time = 0, the denominator is always (erf(0.377) 0.41 while the numerator is 1 giving the temperature answer in negative. hence i thought it is a printing error or any other logical explanation ? Is it something to do with the error functions ?
I would really really appreciate your response.
Thanks & Regards
Abdur