本研究使用可視化平板熱管，以水為工作流體，量測並觀察雙層200目銅網毛細、溝槽毛細與複合式溝槽/銅網毛細三種熱管的操作特性。在燒結雙層200目銅網的情況下其最大熱傳量為24W，而溝槽毛細熱管的最大熱傳量為14W。採用複合式溝槽/銅網毛細時，蒸發過程在不同加熱量範圍呈現不同模態，熱阻值也呈階段式上升。最大熱傳量可以提高到66W，並且在小於44W時，蒸發熱阻值僅有0.05~0.07 Kcm2/W。更進一步增加傾角至45°及90°時，最大熱傳量仍達44W，而熱阻值與水平擺放時差異不大，如此顯示此種複合式熱管可以大幅提升熱管性能。
可視化觀察顯示複合式燒結溝槽/銅網毛細可以提供更多的毛細交接處，使其能夠在水平操作下維持在部分乾化卻穩定蒸發的階段。在蒸發區動態行為的表現上較相近於溝槽熱管，工作流體的聚光性端部彼此間具有獨立性。另外，在本文中的所有不同毛細實驗中，皆未觀察到核沸騰的現象。

This work presents visualization and measurement of the evaporation resistance for operating flat-plate heat pipes with composite groove/mesh wicked. For comparison, experiments are also conducted for heat pipes with a groove or a mesh wick. The performances of these heat pipes are compared under different inclination angles. The parallel, U-shaped grooves with a width of 0.18 mm and a depth of 0.1 mm are sintered with a layer of 200 mesh copper screen covering the top of the grooves. With stepwise increase of heat load Q, the behavior of the working fluid in the groove/mesh wicked was visualized and the evaporator and condenser resistances were measured. Horizontally, different stages are identified with increasing heat load. For Q < 44 W, the evaporator can be fully wetted and the evaporator resistance ranges between 0.05~0.07 Kcm2/W; for 44 W < Q < 66 W, partial dryout appears in the evaporator, with the evaporator resistances jump to about 0.3 Kcm2/W; for Q > 66 W, the evaporator fully dries out with runaway evaporator resistances. At inclination angle of 45°, 60°, or 90°, Qmax could remain at about 44 W. In contrast, Qmax is 14 W for the groove wicked heat pipe and 24 W for the 2 × 200 mesh heat pipe under the horizontal orientation. The results show that the composite groove/mesh wick provides strong capillary force yet low flow resistance to yield high Qmax even for high inclination angles. In addition, no boiling is observed in all present tests.

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