Experimental investigation on the performance of CPU coolers: Effect of heat pipe inclination angle and the use of nanofluids

• Published in: Microelectronics and reliability 2013-12, Vol.53 (12), p.1954-1961
• Main Authors: Yousefi, T., Mousavi, S.A., Farahbakhsh, B., Saghir, M.Z.
• Format: Article
• Language: English
• Subjects: Applied sciences; Central processing units; Cooling effects; Cross-disciplinary physics: materials science; rheology; Design. Technologies. Operation analysis. Testing; Electronics; Exact sciences and technology; Heat pipes; Heat transfer; Inclination angle; Integrated circuits; Integrated circuits by function (including memories and processors); Materials science; Nanofluids; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Other topics in nanoscale materials and structures; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Thermal resistance; Thresholds
• ISSN: 0026-2714; 1872-941X
• DOI: 10.1016/j.microrel.2013.06.012

•Heat pipe for cooling CPU is optimized to operate horizontally.•There is a thershold angle of inclination that limits the operation of a heat pipe.•Nanofluids improve heat pipe performance for CPU cooling. An experimental study of heat transfer performance of a CPU cooling heat pipe, examining the effects of inclination angle and nanofluids, has been conducted. It is shown that inclination angle of the unit has a significant effect on the cooling process, since it directly influences the operation of the evaporator. The effect is mainly due to the capillary effect and boiling limits of the heat pipe. The results demonstrate that for a given CPU temperature, there is a threshold angle at which the thermal resistance of the heat pipe increases dramatically. It is observed that as the CPU temperature increases, the threshold angle decreases from 60° to 30°. Introduction of 0.5wt% Al2O3 nanoparticles to the water coolant of heat pipe has led to a decrease in thermal resistance. It is shown that at 10W, the presence of nanofluid has reduced the thermal resistance by 15%, while at 25W, the thermal resistance has dropped by 22%.