An Experimental Study of Thermally-Induced Flow Oscillations in Supercritical Helium

Abstract

The density wave stability boundary has been experimentally determined for super critical helium flowing in a long (L = 185 m), heated channel of high aspect ratio (L/d = 46 (10)4). A pressure drop ratio and the fluid expansion ratio correlate the oscillation inception point data. The growth of enthalpy (temperature) perturbations in a heated channel has been experimentally verified. During the density wave oscillation, the channel exit temperature and inlet mass flow were observed to be in phase, and the oscillation period was close to twice the fluid transit time. All three observations agree with a simple incompressible flow model. Oscillation amplitudes as great as 11 K and 100 percent of inlet flow were observed.

Two-phase flow instabilities: A review

“…Another very interesting investigation was carried out by Daney et al [145]. In this work, DWO II are studied in a long test section (L/D = 46000) using supercritical helium as working fluid to simulate superconducting power-transmission lines.…”

The stability boundary for supercritical flow in natural convection loops

“…Daney et al (1979) performed an experimental study of supercritical helium flowing in a heated channel and reported density-wave type of flow oscillations. Analytical results were not given, but formulations were derived to support the understanding presented.…”

Thermally Driven Convection in Enclosed Compressible Fluids

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