A stainless steel acetone heat pipe with and without carbon fiber wick has been investigated under different angles of inclination in top and bottom heating modes. A comparison between the heat transfer rates at the condenser with and without carbon fiber wick has been done under constant cooling water flow rate at the condenser and at different evaporator temperatures. As the results show, the carbon fiber wick returns the liquid back to the evaporator up to a height of 200 mm from the horizontal. Simultaneously, in the operating temperature range of 40-90° C this wick exhibits a noticeable thermal resistance at a thickness more than 0.5 mm.
The above carbon fiber material has been used in a flexible corrugated heat pipe 10 m long, having 20.5 mm maximum external diameter to level the temperature in the case of numerous alternating heat supply and heat removal sections. The efficiency of such a technique of increasing isothermality of elongated objects with distributed heat release is shown.