Thermal Image Analysis on the Axial Temperature Distribution of an AGHP (Axial Grooved Heat Pipe)

The wall temperature field on the condenser section of an AGHP (Axial Grooved Heat Pipe) is measured by infrared thermal imaging technology, and the temperature field information on condenser wall is obtained in the horizontal and vertical working conditions and different temperature conditions. In accordance with the temperature field, Combination of the interaction characteristics between vapor-liquid two-phase annular flow, and by calculating, the accuracy to predict the outcome on non-condensable gas region is verified. Based on the distance to evaporator outlet, the condenser of the AGHP is divided into four regions for analysis. The zone I is closest to evaporator outlet and zone IV is located at the end of condenser. There are different characteristics in 4 zones for the AGHP with different vacuum degree and working conditions. On the conditions of horizontal working status, for the high vacuum AGHP, steadily working region, small fluctuations region, large fluctuations region and temperature recovery region will appear in turn. However for the low vacuum one, the single temperature fluctuation region and a linear decline region come forth followed by the abnormal increase region and steadily working region. Recurring to the analysis of wall temperature information, the characteristics of two-phase vapor-liquid phase change heat transfer and capillary driven flow inner the AGHPs can be discerned qualitatively or semi-quantitatively and some of the laws, Such as vacuum degree, two-phase flow instability are conjectured. The research content in this paper will redound to understanding inner working mechanism for an AGHP or a small heat pipe, and at the same time, provide theory evidences for heat pipe testing in the service of mass production.