Monitoring and Characterizing of Hard Disk Drive Thermal Sources

Abstract

The growth of the hard disk drive's (HDD) capacity and its high performance have been instrumental in meeting the demands of a diverse spectrum of applications. However, thermal effects in HDD may cause several problems, such as thermal expansion, which causes read/write error due to misalignment, and thermal protrusion, which may cause contact between the magnetic head and disk, resulting in a HDD crash. To study the effects of temperature generated within an HDD, a Hitachi HDD (operating at 15000 rpm) was subjected to 12 different ambient temperatures, while thermal distributions of its head cap and disk were obtained using an infrared thermography system. The results show that the temperature within the HDD increases with the ambient temperature and time. However, the different ambient temperatures did not affect the thermal distribution pattern within the HDD. By comparing the results with ANSYS simulation, it was noted that the simulated result lacks details on some thermal conditions of certain regions, and the results of the simulated temperatures of the components within the HDD were also observed to be overpredicted.

Dynamic interaction of heat transfer, air flow and disc vibration of disc drives — Theoretical development and numerical analysis

“…However, to evaluate the inherent heat transfer property of the enclosure system, and to provide an equivalent case to analyse effects of disc rotation on the heat convection and aerodynamic heating, constant P S and P B are used in the following theoretical analysis in this paper. From Ng et al [21], Tan et al [22] and Yang et al [23], the heat generation powers of the shaft base and enclosure base are selected approximately as P S ¼ 3 W and P B ¼2 W. In addition, some fundamental physical parameters of air, disc, shaft and enclosure are listed in Table 4.…”

“…These are not quite true for hard/optical disc drives in an enclosure and with the heat sources of heat flux type, as indicated theoretically and experimentally by Cho et al [13], Ng et al [21], Tan et al [22] and Yang et al [23]. (2) The aerodynamic heating effect due to fluid's viscous dissipation was considered to be small and even neglected in the energy equation of the rotating disc systems [10][11][12][14][15][16][17]19,20], whereas the decrease of disc temperature at its outer edge found in the numerical simulation cannot be confirmed by the experimental observation by Kameya et al [24].…”

Heat Source Analysis of Hard Disk Drives with Different Wall Conditions using Infrared System

“…The camera head of the IR system was placed 50 cm from the HDD as the system has a minimum focus distance of 20 cm [14]. In addition, the background should not have any hot spot which might be reflected off the plastic cover surface and thus affecting the measurement.…”

“…There are five ways to determine the emissivity of a material to ensure accurate temperature measurements [13][14][15]:…”