[en] In the course of He II-He I phase transition studies, one phase of the investigations has been concerned with free convection in He I with the aim of simulating the heat transfer in rotating superconducting windings. A geometry similar to C-frame loops has been used in studies of free convection between the lambds-curve and the transposed critical curve at pressures between 0.3 and 1.5 MPa. Related model calculations have been carried out for cellular convection. A comparison of the data obtained shows reasonable agreement with the model results

[en] Short communication

[en] An attempt to account for microcharacteristics of boiling substance has been made in order to increase the accuracy and broaden the scope of heat transfer computations for boiling liquids with sharply contrasting properties. The following characteristics were used to systematize substances and to divide them into thermodynamically-identical groups: relative molecular mass of substance; similarity of intermolecular bond types; intermolecular interaction energy value. An energy table of the molecular system describing physical intermolecular properties of substances during transformations from liquid to vapor has been summarized basing on these characteristics

[en] Short communication

[en] Known mechanisms of heat transfer are ranked according to the efficiency of heat conversion at the maximum work load, according to Alikhanov’s thermodynamic principle of maximum power.

[en] The present problem deals with the magnetohydrodynamic boundary layer flow of a free convective heat transfer in a square cavity filled with nanofluid-saturated porous medium with the effects of different nanoparticles in the presence of thermal radiation. A uniform magnetic field is applied horizontal to the cavity. The top and bottom horizontal walls of cavity considered adiabatic, while the vertical walls are kept at constant temperatures. The governing partial differential equations are solved by finite element method of Galerkin weighted residual scheme. Numerical results are obtained for different values of the Rayleigh number, magnetic parameter, radiation parameter and nanofluid volume fraction. The overall investigation of variation of streamlines, isotherms and Nusselt numbers are presented graphically. To examine the accuracy, the present results are compared with the available results. (author)

No abstract available

[en] Condensation heat transfer coefficients (HTCs) of HCFC22, HCFC123, HFC134a and HFC245fa are measured on a horizontal plain tube 19.0 mm outside diameter. All data are taken at the vapor temperature of 39 .deg. with a wall subcooling temperature of 3-8 .deg. C. Test results show the HTCs of newly developed alternative low vapor pressure refrigerant, HFC245fa, on a smooth tube are 9.5% higher than those of HCFC123, while they are 3.3% and 5.6% lower than those of HFC134a and HCFC22, respectively. Nusselt's prediction equation for a smooth tube underpredicts the measured data by 13.7% for all refrigerants, while a modified equation yielded 5.9% deviation against all measured data. From the view point of environmental safety and condensation heat transfer, HFC245fa is a long-term good candidate to replace HCFC123 used in centrifugal chillers

[en] This book presents reprints of papers written by Wilhelm Nusselt and Ernst Schmidt, who were pioneers in the development of heat transfer theory and applications

[en] A Comment on the Letter by Brian R.Hunt and Edward Ott, Phys.Rev.Lett.76, 2254 (1996). The authors of the Letter offer a Reply. copyright 1998 The American Physical Society