Effect Of Pore Structure On Heat Transfer Characteristics Of Ordered Porous Copper

Ordered porous copper with elongated pores has been fabrication by a unidirectional solidification method under a pressurized gas mixture of hydrogen and argon. Its high permeability and big specific surface area may be making great in increasing the contact area of the fluid and heat sink material, that it can improve the heat dissipation efficacy. This page based on the ordered porous fund of in information technology and aviation aerospace field, carried out the fundamental researches of fabrication of ordered porous copper and their heat properties. The conclusion of the present study is as follows:Ordered porous copper with different porosity and different pore diameter has been fabrication by a unidirectional solidification method.The measurements were performed with different porosity of ordered porous copper, the results show that the coefficients of thermal expansion (CTE) of ordered porous copper increase rapidly to a constant value after with the increase in temperature. When the temperature in 40～130℃and the majority of pores are clogged, the CTE of ordered porous copper increase slowly in porosity and large than pure copper. In case of the most of pores are penetrated, the larger relative value of porosity and pores diameter, the lower CTE of ordered porous copper. When the temperature be over 130℃, the CTE of lotus metals does not depend on the existence of the pores, the CTE of lotus metals is in agreement with that of the matrix metals.An experimental investigation on flow resistance characteristics of ordered porous copper heat sinks has been first performed. It has found that the ordered porous copper fin with smaller pore diameter can produce larger pressure differential under the same fin porosity; when the pore diameter is a constant value, larger porosity can produce larger pressure differential. The flow resistances increases as the increasing volume flow rate which demonstrates the importance of the fin porosity and pore diameter. The laminar flow regime and solid filling layer can predict friction factor for ordered porous copper heat sink. There is a change in the relationship of friction to Reynolds number around Re=30. It is necessary to investigate the characteristics at this region. Heat transfer characteristics associated with the forced flow of de-ionized water over ordered porous copper heat sink have been experimentally investigated. It is shown that the ordered porous copper fin with smaller pore diameter can produce larger heat transfer coefficient under the same fin porosity and the same volume flow rate. When the pore diameter and volume flow rate are all constant value, the larger fin porosity the greater heat transfer coefficient. When the fin porosity is 46.8% and the pore diameter is 0.416mm, the ordered porous copper fin were found to have a maximum heat transfer coefficient value 32000W/(m2K) which is 4 times greater than the conventional groove fins. The dependence of the heat transfer characteristics on the Reynolds number is considerably notable. The total thermal resistance decreases rapidly to a constant value after the increasing pumping power. When the pump power reaches a certain value, rely on increasing pump power have been unable to effectively improve the heat transfer effect. It is not necessary to effectively improve the heat transfer effect rely on increasing pump power.