Shear viscosity of liquid4He and3He-4He mixtures, especially near the superfluid transition

Wang, S.; Howald, C.; Meyer, Horst

doi:10.1007/bf00692451

Cited by 87 publications

(6 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Quantitatively, the observed thickness is about three to four times less than predicted using reported values for the shear viscosity of helium [38]. Although this discrepancy could be explained by an error in our calculated conversion from capacitance to thickness 17 , such a level of error seems unlikely.…”

Section: The Impact Velocity Of Dropletscontrasting

confidence: 63%

Effect of spray cooling on heat transfer in a two-phase helium flow

Perraud¹,

Puech²,

Thibault³

et al. 2013

Cryogenics

View full text Add to dashboard Cite

International audienceIn this paper, we describe an experimental study of the phenomenon of spray cooling in the case of liquid helium, either normal or superfluid, and its relationship to the heat transfer between an atomized diphasic flow contained in a long pipe, and the pipe walls. This situation is discussed in the context of the cooling of the superconducting magnets of the Large Hadron Collider (LHC). Experiments were conducted in a test loop reproducing the LHC cooling system, in which the vapor velocity and temperature could be varied in a large range. Shear induced atomization results in the generation of a droplet mist which was characterized by optical means. The thin liquid film deposited on the walls by the mist was measured using interdigitated capacitors. The cooling power of the mist was measured using thermal probes, and correlated to the local mist density. Analysis of the results shows that superfluidity has only a limited influence on both the film thickness and the mist cooling power. Using a simple model, we show that the phenomenon of spray cooling accounts for the measured non linearity of the global heat transfer. Finally, we discuss the relevance of our results for cooling the final focus magnets (inner triplets) in an upgraded version of the LHC

show abstract

Section: The Impact Velocity Of Dropletscontrasting

confidence: 63%

Effect of spray cooling on heat transfer in a two-phase helium flow

Perraud¹,

Puech²,

Thibault³

et al. 2013

Cryogenics

View full text Add to dashboard Cite

show abstract

“…The universality hypothesis means that ξ is independent of x, so that we may consider A and B to be defined by Eqs. (36) and (38). Then the only dependence of the superfluid transition temperature on x is through the explicit factor of (1 − x) −2/3 in Eq.…”

Section: He-4 He Mixturesmentioning

confidence: 96%

“…Unfortunately there seems to be no such viscosity measurements for a wide range of pressures as that of Goodwin 33 for pure 4 He. Though there exists a recent investigation 36 of η in mixtures it deals only with pressures near the saturated vapor pressure. Above T λ (at T ∼ 3 K) the viscosity at s.v.p.…”

Section: He-4 He Mixturesmentioning

confidence: 99%

Superfluid transition temperature from the Lindemann-like criterion

Apenko

2000

Phys. Rev. B

View full text Add to dashboard Cite

We further analyze the recently proposed criterion, according to which a superfluid transition occurs whenever the r.m.s. displacement of a particle from its initial position in imaginary time reaches a certain fraction of the interparticle distance. The critical temperature T λ is expressed in terms of the single particle mobility. Within the Drude approximation for the mobility T λ is determined by the friction coefficient (or by the viscosity for dense liquids). To check the validity of the criterion the resulting formula is applied to non-ideal Bose gas, to liquid helium and to 3 He-4 He mixtures. A reasonable qualitative agreement with available experiments is obtained in all cases. In the case of the Bose gas the present approach results also in an upper bound on the peak value of T λ /T 0 λ , where T 0 λ is the critical temperature for the ideal gas.

show abstract

“…The entries draw on information published electronically by Donnelly [49]. Historically, viscosity measurements have been attempted with rotating cylinders [50,51], damped fine-wire vibration [52,53], torsional quartz crystals [54], and torsional oscillators [55]. The rotating cylinder viscometer measures the shear viscosity η directly, whereas the other methods measure the kinematic viscosity η/ρ n , so that ρ n must be independently measured to extract η.…”

Section: Helium IImentioning

confidence: 99%

Interpreting Superfluid Spin Up Through the Response of the Container

Eysden

Melatos

2011

J Low Temp Phys

View full text Add to dashboard Cite

A recipe is presented for interpreting non-invasively the transport processes at work during relaxation of a cylindrical, superfluid-filled vessel, after it is accelerated impulsively and then allowed to respond to the viscous torque exerted by the contained fluid. The recipe exploits a recently published analytic solution for Ekman pumping in a two-component superfluid, which treats the back-reaction self-consistently in arbitrary geometry for the first time. The applicability of the recipe to He II, 3 He, 3 He-4 He mixtures and Bose-Einstein condensates is assessed, and the effects of turbulence discussed.

show abstract

Shear viscosity of liquid4He and3He-4He mixtures, especially near the superfluid transition

Cited by 87 publications

References 31 publications

Effect of spray cooling on heat transfer in a two-phase helium flow

Effect of spray cooling on heat transfer in a two-phase helium flow

Superfluid transition temperature from the Lindemann-like criterion

Interpreting Superfluid Spin Up Through the Response of the Container

Contact Info

Product

Resources

About