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.