Heat transfer characteristics of liquid nitrogen for cyclic heating

被引：6

作者：

Fuchino, S ^{[1
]}

Tamada, N ^{[1
]}

Ishii, I ^{[1
]}

Okano, M ^{[1
]}

机构：

[1] Electrotech Lab, Tsukuba, Ibaraki 8568, Japan

来源：

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY | 2000年 / 10卷 / 01期

关键词：

D O I：

10.1109/77.828532

中图分类号：

TM [电工技术]; TN [电子技术、通信技术];

学科分类号：

0808 ; 0809 ;

摘要：

Bubble formation and the critical heat flux to transit to boiling state for cyclic heat inputs have been investigated using a platinum - 0.5at% cobalt (Pt-Co) wire and a silver sheathed Bi-2223 tape, in order to evaluate the cooling stability for superconducting AC power apparatus. Sinusoidal cyclic heat inputs ranging from 2 to 150 Hz were applied to a horizontal thin wire immersed in a pool of saturated liquid nitrogen under normal atmospheric pressure. A high-speed video camera with a frame speed of 1000 frames/s has been used to observe bubble formation around the wire. The bubble frequency and the critical heat flux to transit to boiling state have been measured for each frequency. As a result, it has been found that the bubble frequency and the critical heat flux have depended on the heating frequency. The same experiment has been performed on a silver sheathed Bi-2223 tape, however, the mechanism of bubble formation Is different. The dependence of the critical heat flux on the heating frequency has been also observed.

引用

页码：1526 / 1529

页数：4