Helium cryostat for experimental study of natural turbulent convection

0350813 - ÚPT 2011 RIV US eng J - Článek v odborném periodiku
Urban, Pavel - Hanzelka, Pavel - Králík, Tomáš - Musilová, Věra - Skrbek, L. - Srnka, Aleš
Helium cryostat for experimental study of natural turbulent convection.
Review of Scientific Instruments. Roč. 81, č. 8 (2010), 085103 :1-5. ISSN 0034-6748. E-ISSN 1089-7623
Grant CEP: GA AV ČR KJB200650902; GA MŠMT ED0017/01/01
Výzkumný záměr: CEZ:AV0Z20650511
Klíčová slova: Rayleigh-Benard convection * ultimate regime
Kód oboru RIV: BK - Mechanika tekutin
Impakt faktor: 1.598, rok: 2010

ublished experiments on natural turbulent convection in cryogenic He-4 gas show contradictory results in the values of Rayleigh number (Ra) higher than 10(11). This paper describes a new helium cryostat with a cylindrical cell designed for the study of the dependence of the Nusselt number (Nu) on the Rayleigh number (up to Ra approximate to 10(15)) in order to help resolve the existing controversy among published experimental results. The main part of the cryostat is a cylindrical convection cell of 300 mm in diameter and up to 300 mm in height. The cell is designed for measurement of heat transfer by natural convection at pressures ranging from 100 Pa to 250 kPa and at temperatures between 4.2 and 12 K. Parasitic heat fluxes into the convection medium are minimized by using thin sidewalls of the bottom and top parts of the cell. The exchangeable central part of the cell enables one to modify the cell geometry.
Trvalý link: http://hdl.handle.net/11104/0190716