Abstract:

The temperature characteristics and their effect factors of a radial eccentric gravity heat pipe were investigated experimentally under natural convection and forced convection. For the test, a radial eccentric gravity heat pipe was fabricated with two eccentric pipes of unequal diameters that create an annular vapor space. The radial eccentric heat pipe was sealed with a high vacuum valve by which the filling ratio could be changed. The experiments were performed in the range from 70 to 100℃ and filling ratios (FR) from 15% to 60%. The temperature stability, uniformity and distributions of the outer surface of the outer pipe and the inner surface of the inner pipe were affected by various factors, such as filling ratios, the locations of the heater controller probe and the cooling capabilities of the inner pipe. The wall temperature distributions on both the outer surface of the outer pipe and the inner surface of the inner pipe were monitored and analyzed. The results indicated that the temperature stability of the inner surface of the inner pipe was about ±0.024℃ for 2 h. The maximum temperature difference was 0.142℃ over 20 cm in the central part of the measuring zone and the minimum temperature of the outer surface of the outer pipe appeared underneath the inlet of cooling air. The results also showed that the radial eccentric gravity heat pipes were very promising in the applications of temperature calibration field.

Key words: radial eccentric heat pipe, vaporization, condensation, heat transfer, filling ratio, temperature stability, temperature uniformity

摘要：

研制了不锈钢-水重力径向偏心热管，在70～100℃范围内实验研究了该热管的温度特性及其影响因素。当冷凝段处于自然对流时，较大充液率、上部控温方式和较低运行温度有利于提高冷凝段及蒸发段壁面温度的稳定性和均匀性；冷凝段内壁中心处的温度稳定性2 h内为±0.024℃，其中心段20 cm内温度均匀性为0.142℃。当采用强制对流冷却时，增大充液率、降低冷却能力可提高蒸发段平均温度，并改善蒸发段外壁面温度均匀性。此外，分析了热管通过相变换热及其热容来提高温度稳定性和均匀性的传热机理。此类热管在温度校准领域具有较好的应用前景。

关键词: 径向偏心热管, 汽化, 凝结, 传热, 充液率, 温度稳定性, 温度均匀性