Compression heating of glass-ceramics
Compression heating of glass-ceramics
(OP)
I would like to know how to determine the
additional heating of a glass ceramic (similar to Schott Robax)when compressed to 25,000 psi (172 MPa). The ambient is 625 degrees C and compression may raise the temperature beyond the rating of 700 degrees C but I don't know how to calculate.
additional heating of a glass ceramic (similar to Schott Robax)when compressed to 25,000 psi (172 MPa). The ambient is 625 degrees C and compression may raise the temperature beyond the rating of 700 degrees C but I don't know how to calculate.





RE: Compression heating of glass-ceramics
Assuming your glass has an average compressibility factor of 5E-4 per MPa, the change in volume would be:
ΔV/V=5E-4·172=0.086=8.6%
The work done to do so per unit volume is
Pavg·ΔV/V=172·0.086/2=7.4E6 J/m3
Assuming now a relative density of 2 for your material and a specific heat of 1000 J/kg°C (didn't check any handbook, just rough figures I have in mind), and assuming that all that work goes into heating the body (certainly far from being true) we have:
ΔT=7.4E6/2000/1000=3.7°C
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