Abstract
Data center has been built with spread of cloud computing. Further, electric power consumption of it is growing rapidly. High power cooling fans are used for servers in the data center and there is a strong demand to increase power of it because of increase of quantity of heat from the servers. Contra-rotating rotors have been adopted for some of the high power cooling fans. In addition, the miniaturization has become necessary to the cooling fan due to miniaturization of electronic devices. Therefore, the internal flow of the cooling fan is very complicated, there are many unexplained point. It is important to clarify complicated unsteady internal flow condition to achieve the high performance cooling fans. Unsteady numerical analysis of a cooling fan with 40mm square was conducted and influences of unsteady vortex behavior on internal flow at the inlet of fan and front rotor was investigated numerically in this research.
