Abstract
Determination of temperature dependent thermal
diffusivities using a transient
symmetrical method was studied. The thermal diffusivity
is determined from the
temperature profile in a specimen constructed of thin
slabs and heated
symmetrically
from both sides. The thermal diffusivity is determined as
the ratio of the time
derivate
and the second spatial derivate at the position of the
extremum of temperature.
A numerical method was developed to calculate the thermal
diffusivity as a
function of
time including the confidence interval of the
diffusivity. The numerical
methods were
validated by using numerically calculated temperature
profiles for a material
with
known thermal diffusivity.
Preliminary tests were conducted to investigate the
practical applicability of
the method.
The method proved to work for an inert material when no
changes of geometry of
the
sample occurred. If reactions, convection, or substantial
thermal expansions
causing
gaps inside the specimen occur, the results will not be
well-defined.
| Original language | English |
|---|---|
| Place of Publication | Espoo |
| Publisher | VTT Technical Research Centre of Finland |
| Number of pages | 26 |
| ISBN (Print) | 951-38-4345-9 |
| Publication status | Published - 1993 |
| MoE publication type | Not Eligible |
Publication series
| Series | VTT Tiedotteita - Meddelanden - Research Notes |
|---|---|
| Number | 1452 |
| ISSN | 1235-0605 |
Keywords
- fire safety
- temperature
- measurement
- thermal diffusivity
- thermophysical properties
- heat transfer
- calculations
- utilization
- experimentations
- numerical analysis
- test methods
- transiet analysis
- time
- mineral wool
- calcium silicates
- insulating boards
- geometry
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Cite this
Kokkala, M., & Baroudi, D. (1993). A transient symmetrical method for the measurement of temperature dependent thermal diffusivity. VTT Technical Research Centre of Finland. VTT Tiedotteita - Meddelanden - Research Notes, No. 1452