TY - JOUR
T1 - Experimental investigation of natural convection in a supercritical binary fluid
AU - Long, Z. Q.
AU - Zhang, P.
AU - Shen, B.
AU - Li, T.
N1 - Funding Information:
This research is supported by the National Natural Science Foundation of China under the Contract No. 51376128. B. Shen gratefully acknowledge financial support by World Premier International Research Center Initiative (WPI), MEXT , and International Institute for Carbon-Neutral Energy Research (WPI-I 2 CNER), Kyushu University, Japan. We are grateful to Dr. Akihiro Nakano for the courtesy of the experimental facility.
Publisher Copyright:
© 2015 Elsevier Ltd. All rights reserved.
PY - 2015/7/27
Y1 - 2015/7/27
N2 - We experimentally investigate natural convection of a supercritical nitrogen/argon (0.9/0.1 in molar fraction) binary fluid in a bottom-heated cavity with an aspect ratio of 2.5 in the present study. We obtain the development process of natural convection by the holographic interferometry technique, which is divided into three phases: Stable thermal boundary layer (TBL) phase, Developing phase, and Stable flow phase. After thermal perturbation applied at the bottom, the TBL is thickened and then loses stability and thermal plumes are generated, which signifies the onset of natural convection. Thereafter, natural convection gradually develops to a stable state. As the heat input increases, the experimental results show that the convection grows more intense and spreads deeper into the bulk of the fluid. The TBL in supercritical binary fluid is hydrodynamically more unstable and the natural convection develops faster than the case of a pseudo-pure fluid due to the existence of the Soret effect (SE) and the Dufour effect (DE). The SE and DE are analyzed by comparing the temperature variation in the bulk of a supercritical nitrogen/argon binary fluid with the case of its pseudo-pure fluid counterpart, showing that they enhance the heat transfer in the fluid and further accelerate the development of natural convection.
AB - We experimentally investigate natural convection of a supercritical nitrogen/argon (0.9/0.1 in molar fraction) binary fluid in a bottom-heated cavity with an aspect ratio of 2.5 in the present study. We obtain the development process of natural convection by the holographic interferometry technique, which is divided into three phases: Stable thermal boundary layer (TBL) phase, Developing phase, and Stable flow phase. After thermal perturbation applied at the bottom, the TBL is thickened and then loses stability and thermal plumes are generated, which signifies the onset of natural convection. Thereafter, natural convection gradually develops to a stable state. As the heat input increases, the experimental results show that the convection grows more intense and spreads deeper into the bulk of the fluid. The TBL in supercritical binary fluid is hydrodynamically more unstable and the natural convection develops faster than the case of a pseudo-pure fluid due to the existence of the Soret effect (SE) and the Dufour effect (DE). The SE and DE are analyzed by comparing the temperature variation in the bulk of a supercritical nitrogen/argon binary fluid with the case of its pseudo-pure fluid counterpart, showing that they enhance the heat transfer in the fluid and further accelerate the development of natural convection.
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U2 - 10.1016/j.ijheatmasstransfer.2015.07.019
DO - 10.1016/j.ijheatmasstransfer.2015.07.019
M3 - Article
AN - SCOPUS:84937803038
SN - 0017-9310
VL - 90
SP - 922
EP - 930
JO - International Journal of Heat and Mass Transfer
JF - International Journal of Heat and Mass Transfer
ER -