Theoretical And Experimental Research On Computer Chip Water-cooling System Driven By Piezoelectric Pump

1. IntroductionWith the development of computer industry, the working frequency of Computer Processor Unity (CPU) gets higher and higher. Experts estimates that working frequency of Prescott processor will reach 4-5 GHz in the near future, then its heat emission power will reach over 100 W. So CPU heat emission becomes the main problem for the rapid development of computer. In order to GIVE A COOL HEART to the computer, some powerful companies begin to cool the chip with water-cooling system, instead of traditional wind-cooling system. The biggest merit of water-cooling system is transferring heat to radiator without decreasing the temperature in the machine box, but cooling computer component with liquid. Only if the amount of emitted heat produced by radiator pipes is improved, the fan's rotation speed can be decreased, even the fan can be removed.But traditional water-cooling systems have all kinds of shortcomings, which are as follws,1. Output pressure of the centrifugal pump is low.2. Metal or plastic pipe is needed when connecting the water tank, pump and CPU heat sink, so system installation is difficult.3. Coolant will be leaked when it is pumped chronically in the water tank, pump and pipe, so lowering the flow rate in system and a bigger water tank are needed.For the above reason, we adopt a new actuator, piezoelectric (PZT) pump to drive this system. Because of the bigger pressure of PZT pump than that of centrifugal pump, much thinner pipe is used without much loss of liquid velocity. In order to ensure PZT pump's reliability, a new structure pump is developed, double series-wound chamber PZT pump with whole-opening valves. Its output parameters are 1000 ml/min and 7.5 KPa with power of 200V/180Hz. This kind of pump is free from irrigating and can meet the demand of CPU water-cooling system. Therefore, structural design and theoretical analysis of the CPU water-cooling system's components, such as PZT pump, water-cooling module and radiator.2. Theoretical research and experimental analysis of the passive whole-opening valve Vibration of PZT diaphragm, the structure of valve and the height of pump chamber are thethree main factors that affect the PZT pump's output capability. Through theoretical and experimental analysis of PZT diaphragm, such conclusions are drawn. Firstly, when working with low frequency power, the bigger the pump volume changes, the better is the pump output, when working with high frequency power, it's the best coupling frequency of pump volume change and valves, usually 180 Hz, that affects greatly pump output, but the pump volume change produced by the vibration of PZT diaphragm.The structure of valve affects not only the structure of pump, but also the pump output ability. Through the analysis of whole-opening valve's transiting character, the conclusion that the flow rate via valve is proportioned with the pressure difference and the cube of valve opening height. By comparing the pump of whole-opening valve with that of lame papilionaceous valve, we...