Heat transfer performance of a micro heat pipe array filled with copper foam

To investigate the method to enhance the heat transfer performance of a micro heat pipe array, two types of copper foam with different pore-diameters and porosities were added inside the micro heat pipe array with rectangular micro-fins, respectively, to form a composite wick inside the micro heat pipe array. An experimental investigation was conducted to explore the relationship between the thermal resistance and heating power of the copper foam micro heat pipe array across various ambient temperatures. It was found that the addition of copper foam obviously improves the capillary force of the wick and reduce the thermal resistance from 0.635 K/W to 0.445 K/W and 0.394 K/W, which were 29.9 % and 38.0 %, respectively, at the heating power of about 18 W. The impact of the ambient temperature on the thermal resistance of the copper foam micro heat pipe array depends on the geometry of the copper foam. The study provides a data base for the enhanced heat transfer mechanism of a micro heat pipe array by composite wicks, and acts as a reference for methods to improve the performance of micro heat pipe arrays.