ISSN:
1572-9567
Schlagwort(e):
CO2
;
critical-point phenomena
;
thermal diffusion
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Physik
Notizen:
Abstract Heat transport in supercritical CO2 is studied under microgravity conditions. A large temperature and densityρ region around the critical point is explored (CO2 cells were filled at critical densityρ=ρ c and off-critical densitiesρ=ρ c±0.18ρ c). Local heating is obtained by using a small thermistor located in the bulk fluid. Through interferometric observations, a new mechanism of thermalization has been evidenced. Thermal expansion of a warm diffusing boundary layer around the heating thermistor is responsible for rapid adiabatic heating of the bulk fluid through the emission of pressure waves at the border. The scaled thickness of the thermal boundary layer follows a power law. When the heat flow stops, the bulk adiabatic heating instantaneously vanishes and the temperature relaxation inside the thermal boundary layer follows locally a diffusive process.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF02081275
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