Development of Cooling Structures for Blu-Ray Disc Compatible Optical Disc Drives Using Computational Fluid Dynamics Based on Cartesian Grid Method

Abstract

High-performance, simple cooling structures for optical disc drives compatible with the Blu-ray disc (BD) were developed using unsteady numerical flow simulation based on the Cartesian grid method. In the new structure, an additional hole in the tray outside of the disc induced a secondary upward flow, which is caused by a pressure difference and rotating-disc flow. The secondary flow decreases the ambient air-temperature of the laser diode below the hole, and furthermore it increases the velocity around the laser diode and enhances the heat transfer rate. The experimental results indicate that the cooling effect of the laser diode increases, and the disc vibration is not influenced by the additional hole in the tray. The cooling structures are applied to the so-called super-multi BD drive, which achieved 4X high-speed recording for the first time in the industry.

Investigation of Data Mining Method for Thermal-Fluid Simu-Lation Results Based on Pressure Difference Between Front and Back Sides Using Medial-Surface and Its Application to Thermal Design Problems

“…Optical disc drive The Blu-ray Disc (BD) drive that achieved BD 4X-speed recording and DVD-R 12X speed recording for the first time in the industry in July 2006 was selected to verify the validity of the data mining method. One of the authors developed a new LD cooling structure using CFD simulations [1]. From the simulation results, the author found that the low pressure region induced by the disk rotation is locally formed on the tray, where it is just above the position of the LD.…”

“…Hitachi has been developing a simulation system based on the Cartesian grid method and applying it to various product developments to solve these problems [1]- [2]. In those cases, the entire body of the product is divided into 107-108 order grids using the Cartesian grid.…”

“…In those cases, the entire body of the product is divided into 107-108 order grids using the Cartesian grid. The important thing in such developments lies in (1) finding some useful knowledge from the simulation results data, and (2) quick proper reflection to the product structure. However, the complexity of the internal structure creates highly complicated flow pattern for electronic and IT equipment.…”

Investigation of Data Exploration Method for Thermal-Fluid Simulation Results Using Proper Orthogonal Decomposition

“…The Blu-ray Disc (BD) drive, which achieved BD 4X-speed recording and DVD-R 12X speed recording for the first time in the industry in July 2006, was selected in order to verify the validity of the data exploration method. One of the authors developed a new LD cooling structure using CFD simulations (17) . The simulation results in Figs.…”

“…The effect that the design of each group has in flow field, is discussed here taking past design knowledge consideration (17) . As shown in Fig.…”