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The presence of particles, which can intrude into the gas bearing, is one of the most common factors in the failure of hard disk drives (HDDs). Previous works investigated particle trajectories inside air-filled drives without considering temperature effects on the distribution of particles. Actually, especially for the submicron particle, particle trajectories and trapping status are affected by the temperature gradient since the thermophoretic force cannot be ignored. In this paper, considering major heat generation components such as the spindle motor and voice coil motor (VCM), trajectories and trapping status for AlO particles inside a 2.5 inch helium-filled drive are simulated by the commercial computational fluid dynamics solver FLUENT with user-defined functions (UDFs). The trapping criterion for AlO particles is used as boundary conditions for different colliding surfaces. The results reveal that particles in the air-filled drive will more likely degrade the head-disk interface (HDI) reliability. In addition, after considering the temperature, the particle trapping rate by the disk decreases both inside the air-filled drive and the helium-filled drive. And its reduction inside the air-filled drive is larger. Moreover, small particles will more likely degrade the HDI reliability since they can follow the rotatory flow well and have more chance to collide with the disk surface, and then easily attach onto the disk surface. [ABSTRACT FROM AUTHOR]

Heat-assisted magnetic recording (HAMR) is a new approach, which makes the head write data easily under a low magnetic field using a laser to heat the magnetic media to reduce its coercivity, thus, it is considered to be the next generation of higher recording areal density technology. In this paper, a three-dimensional HAMR finite-element model of hard disk drive (HDD) is developed. The temperature distributions around the laser-heating area on disk surface are investigated when the HDD is filled with air and helium. The cooling effects of the disk rotation and the heat convection in head-disk interface (HDI) are also analyzed. [ABSTRACT FROM AUTHOR]

The reliability and stability of hard disk drives (HDDs) is especially important as the areal recording density increasing rapidly target to 10 Tb/in in the future. The vibration of the Head Gimbals Assembly (HGA) is inevitable by internal fluid flow during operational process. In order to improve this undesirable problem, an acoustic piezoelectric transducer (PZT) actuator which can be used to transform an electric current to an acoustic pressure field, is glued on the HDD cover inner surface to generate acoustic pressure to suppress the flow-induced off-plate vibration (FIOPV) of the HGA. In this paper, a three-dimensional finite element model of HDD is built with an acoustic PZT actuator. The FIOPV of the HGA in the air and helium-filled drives are investigated by fluid-structure interaction simulation method. The acoustic pressure induced vibration (APIV) of the HGA is analyzed by acoustics-piezoelectric-structure interaction simulation method. After that, the suppressed FIOPV after superposing the APIV and the FIOPV is obtained by following the superposition principle. [ABSTRACT FROM AUTHOR]