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针对１００Ｋ以上的高温交流超导磁体的冷却问题，对９０－１６０Ｋ的氮气在五种小高宽比（Ａ＝０．０１３－０．０４７５）矩形通道中的对流换热进行了实验研究和机理分析。实验结果表明，矩形通道高度对传热与流动特性影响显著。随着通道高度的增加，通道进出口压差减小，层流向湍流转变的临界Ｒｅ数增大，层流区Ｎｕ数随通道高度增加而增大，湍流区Ｎｕ数随通道高度变化存在最佳值问题，０．５１ｍｍ为最佳高度。
Aiming at the cooling problem of high temperature AC superconducting magnet above 100K, the convection heat transfer of 90-160K nitrogen in five rectangular channels with small aspect ratio (A = 0.013-0.0475) was studied experimentally and mechanism analyzed . The experimental results show that the height of rectangular channel has a significant influence on the heat transfer and flow characteristics. As the channel height increases, the pressure drop at the inlet and outlet of the channel decreases, and the critical Re number of laminar-to-turbulent transition increases. The Nu number in the laminar flow zone increases with the height of the channel, and the Nu number in the turbulent zone varies with the channel height Value problem, 0.51mm for the best height.