scholarly journals The Transport of Heat Through Narrow Channels by Liquid Helium II

1955 ◽  
Vol 8 (2) ◽  
pp. 206 ◽  
Author(s):  
PG Klemens
Keyword(s):  
Temperature Gradient ◽  
Liquid Helium ◽  
Heat Transport ◽  
Reasonable Agreement ◽  
Normal Fluid ◽  
Narrow Channels ◽  
Helium Ii ◽  
Internal Convection

In narrow channels (~10?4 cm) the observed heat transport is considerably larger than calculated by the internal convection theory. It is suggested that, because of the anisotropy of the distribution cf phonons in the channel walls resulting from the temperature gradient, the normal fluid in the immediate vicinity of the walls is not at rest but flows towards the colder region. The magnitude of the resulting heat transport is in reasonable agreement with the observed discrepancy.

Heat Transfer in Liquid Helium II by Internal Convection

1948 ◽  
Vol 74 (9) ◽  
pp. 1148-1156 ◽  
Author(s):  
F. London ◽  
P. R. Zilsel
Keyword(s):  
Heat Transfer ◽  
Liquid Helium ◽  
Helium Ii ◽  
Internal Convection

VISCOSITY MEASUREMENTS IN LIQUID HELIUM II

1960 ◽  
Vol 38 (10) ◽  
pp. 1376-1389 ◽  
Author(s):  
C. B. Benson ◽  
A. C. Hollis Hallett
Keyword(s):  
Liquid Helium ◽  
Significant Contribution ◽  
Normal Component ◽  
Circular Disk ◽  
Viscous Drag ◽  
Normal Fluid ◽  
Helium Ii ◽  
Torsion Suspension ◽  
Thermal Data ◽  
Cylinder Method

Measurements of the viscosity of liquid helium II have been made using an oscillating sphere. This method avoids the necessity of a "corner" correction unavoidable when a circular disk is used, and therefore eliminates the uncertainty associated with such a correction. Calibration experiments showed the presence of a significant contribution to the observed damping of the oscillations which arose from the viscous drag of the gas surrounding the rod which connected the sphere with the torsion suspension fiber. This damping has been calculated and when applied to the results obtained in liquid helium II, the values of the viscosity of the normal component which were obtained agree with those obtained by the rotating cylinder method within the combined experimental uncertainties. The assumed density of the normal fluid was that obtained from the velocity of second sound, and the most accurate thermal data available.

Normal Fluid Concentration in Liquid Helium II below 1°K

1953 ◽  
Vol 89 (3) ◽  
pp. 662-663 ◽  
Author(s):  
D. de Klerk ◽  
R. P. Hudson ◽  
J. R. Pellam
Keyword(s):  
Liquid Helium ◽  
Normal Fluid ◽  
Helium Ii ◽  
Fluid Concentration

Normal-Fluid Densities in Liquid Helium II under Pressure

1969 ◽  
Vol 186 (1) ◽  
pp. 255-262 ◽  
Author(s):  
R. H. Romer ◽  
R. J. Duffy
Keyword(s):  
Liquid Helium ◽  
Normal Fluid ◽  
Helium Ii

THE OSCILLATING SPHERE AT LARGE AMPLITUDES IN LIQUID HELIUM

1956 ◽  
Vol 34 (7) ◽  
pp. 668-678 ◽  
Author(s):  
C. B. Benson ◽  
A. C. Hollis Hallett
Keyword(s):  
Liquid Helium ◽  
Reynolds Numbers ◽  
Total Density ◽  
Normal Fluid ◽  
Helium Ii ◽  
Onset Of Turbulence ◽  
Helium Gas ◽  
Critical Amplitudes ◽  
Period Of Oscillation ◽  
Oscillating Sphere

Measurements of the damping of the oscillations of a sphere which decay from an initial deflection ~ 10 radians show that two critical amplitudes, denoted by [Formula: see text] and [Formula: see text], may be defined in liquid helium II. The decrement is constant at amplitudes below [Formula: see text] (a few tenths of a radian), and is caused by the damping due to the viscosity of the normal fluid. [Formula: see text] is found to be proportional to the square root of the period of oscillation. Above [Formula: see text] the decrement increases, the superfluid becoming involved in the motion, until it attains another constant value, which is attributed to the viscosity of a single fluid whose density is equal to the total density (ρn+ρδ) of liquid helium II. At a larger amplitude [Formula: see text] (~ 2 radians) the decrement begins to increase linearly with amplitude, and this behavior, which is also found in liquid helium I and in helium gas at 4 °K., is attributed to the onset of turbulence. Reynolds numbers calculated at [Formula: see text] are ~ 200 for helium II, helium I, and helium gas at 4 °K.

A continuum theory of the isothermal flow of liquid helium II

1961 ◽  
Vol 10 (1) ◽  
pp. 113-132 ◽  
Author(s):  
A. A. Townsend
Keyword(s):  
Pressure Gradient ◽  
Liquid Helium ◽  
Flow Rate ◽  
Equations Of Motion ◽  
Reynolds Numbers ◽  
Isothermal Flow ◽  
Mutual Friction ◽  
Normal Fluid ◽  
Helium Ii ◽  
Vortex Lines

Recent work by Hall and Vinen has established that mutual friction between the normal and superfluid components of liquid helium II is caused by interactions between quantized vortex-lines and the normal fluid. If the mean separation of the vortex-lines is small compared with the channel width, the general character of the flow may not depend on the discrete nature of the lines except in so far as this is the cause of the mutual friction. Equations of motion are developed which refer to components of the velocity field with a scale large compared with the line separation, and these are used to discuss the nature of possible turbulent motions. Reasons are given for believing that isothermal flow is very similar to that of a Newtonian fluid, and the theory is developed for turbulent pressure flow along a channel and a circular pipe. The predicted variation of flow rate with pressure gradient is in good agreement with experimental measurements for Reynolds numbers (based on tube diameter and normal fluid viscosity) above 1400, and it is likely that turbulent flow can exist only above this critical Reynolds number. For Reynolds numbers which are not too small, the equations of motion apply to steady ’laminar’ flow and these lead to a relation between flow rate and pressure gradient in reasonable agreement with experiment.

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