Helium cryostat for experimental study of natural turbulent convection

Urban, P.; Hanzelka, P.; Kralik, T.; Musilova, V.; Skrbek, L.; Srnka, A.
August 2010
Review of Scientific Instruments;Aug2010, Vol. 81 Issue 8, p085103
Academic Journal
Published experiments on natural turbulent convection in cryogenic 4He gas show contradictory results in the values of Rayleigh number (Ra) higher than 1011. 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≈1015) 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.


Related Articles

  • Free Fluid Convection in a Closed Contour in a Heat-Conducting Half-Space. Ramazanov, M. // Fluid Dynamics;Jul2005, Vol. 40 Issue 4, p613 

    The steady-state convection of a fluid in a thin porous vertical ring located in a heat-conducting half-plane is considered. For this problem approximate equations are derived. For a circular ring an analytic solution is obtained. For an elliptic ring a numerical-analytic solution is found. The...

  • Semiconvection: theory. Spruit, H. C. // Astronomy & Astrophysics / Astronomie et Astrophysique;Apr2013, Vol. 552 Issue 2, pA76 

    A model is developed for the transport of heat and solute in a system of double-diffusive layers under astrophysical conditions (where viscosity and solute diffusivity are low compared with the thermal diffusivity). The process of formation of the layers is not part of the model but, as observed...

  • Source function approach to turbulence bulk properties. Canuto, V. M.; Cheng, Y.; Hartke, G. J.; Schilling, O. // Physics of Fluids A;Jun91, Vol. 3 Issue 6, p1633 

    A turbulence model to compute bulk properties is presented in which a prescribed source function is used to provide the rate of energy input into the turbulent flow, and the EDQNM model is used to treat the nonlinear transfer in the Navier�Stokes equations. The predictions of the model are...

  • Optimum fields and bounds on heat transport for nonlinear convection in rapidly rotating fluid layer. Vitanov, N. K. // European Physical Journal B -- Condensed Matter;Jan2010, Vol. 73 Issue 2, p265 

    By means of the Howard-Busse method of the optimum theory of turbulence we investigate numerically the effect of strong rotation on the upper bound on the convective heat transport in a horizontal fluid layer of infinite Prandtl number Pr. We discuss the case of fields with one wave number for...

  • Physical model of the dependence of the Nusselt number on the Rayleigh number. Patochkina, O.; Kazarinov, Yu.; Tkachenko, V. // Technical Physics;Nov2016, Vol. 61 Issue 11, p1626 

    The dependence of the Nusselt number on the Rayleigh number at the stage preceding the turbulent regime of convection is substantiated and obtained in analytic form. At this stage, the Nusselt number can be described by the power dependence on the Rayleigh number, which contains five constants....

  • Resistive pressure-gradient-driven instabilities in the transition regime to fully developed turbulence. Garcia, L.; Carreras, B. A.; Lynch, V. E. // Physics of Plasmas;Jan2002, Vol. 9 Issue 1, p47 

    Numerical calculations of resistive pressure-gradient-driven turbulence in toroidal geometry for tokamak plasma edge parameters have been carried out in the unstable regime below the threshold for fully developed turbulence. This threshold is at a β value of about three times the linear...

  • Wavenumber selection in large-amplitude axisymmetric convection. Buell, Jeffrey C.; Catton, Ivan // Physics of Fluids (00319171);Jan86, Vol. 29 Issue 1, p23 

    Unique wavenumbers are calculated for axisymmetric Rayleigh-Bénard convection as a function of the Rayleigh number (R) up to the second critical value for several different Prandtl numbers. The analysis assumes slightly bent rolls (large radius of curvature) and that there exists a horizontal...

  • Natural convection in a differentially heated corner region. Kimura, Shigeo; Bejan, Adrian // Physics of Fluids (00319171);Oct85, Vol. 28 Issue 10, p2980 

    This is a fundamental study of the phenomenon of natural convection in the region formed by a vertical warm wall rising above a cold horizontal wall, or in the region between a cold vertical wall extending downward from a warm horizontal surface. The study consists of scale analysis, numerical...

  • Numerical simulation of two-dimensional convection: Role of boundary conditions. Palymskii, I. // Fluid Dynamics;Jul2007, Vol. 42 Issue 4, p550 

    The problem of two-dimensional, periodic in the horizontal coordinate, convection of an incompressible fluid heated from below between two horizontal planes is considered. The problem is solved in two formulations: with (stress-)free and hard (no-slip) boundary conditions on the horizontal...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics