石墨烯奈米流體應用於電子晶片散熱之研究

Abstract

本研究因應電子晶片散熱需求越來越高而開發石墨烯奈米流體（GNNF）替代水作為水冷式系統的工作流體以提供更佳的散熱性能。本研究首先利用球磨機降低石墨烯（GN）的粒徑並且將其配製為石墨烯奈米流體（GNNF），並使用十二烷基硫酸鈉（SDS）做為分散劑，且SDS與GN濃度呈現1：2時會使GNNF具有最佳的穩定性。此外，諸如GNNF的密度、黏度、比熱與熱傳導係數等基本性質均進行量測以評估GNNF在熱交換領域應用的可行性。最後實際將GNNF應用於中央處理器（CPU）水冷系統進行散熱性能實驗以評估GNNF的熱交換性能。散熱性能實驗的實驗參數分別為四個GNNF濃度（0、0.05、0.1、0.2 wt%）、三個不同的加熱瓦數（50、100、150 W）以及三個不同的流量（2、3.5、5 LPM）。研究結果顯示環境溫度25℃時，GNNF具有最佳散熱能力的濃度為0.05 wt%，並且在高流量與低瓦數的參數下有最高的熱交換量提升率。0.05 wt% GNNF在50 W/5 LPM的熱交換量提升率比水高約13.9%。在環境溫度32℃時，GNNF具有最佳散熱能力的濃度為0.1 wt%。0.1 wt% GNNF在50 W/5 LPM的熱交換量提升率比水高約63.1%。In response to the increasing heat dissipation demand of electronic chips, this study developed graphene nanofluid (GNNF) to replace water as the working fluid of a water-cooled system and provide better heat dissipation performance. In this study, the particle size of graphene (GN) was reduced by a ball miller and formulated into graphene nanofluid (GNNF), and sodium dodecyl sulfate (SDS) was used as a dispersant. The concentrations of SDS and GN showed that 1:2 would give GNNF the best stability. In addition, fundamental characteristics, such as density, viscosity, specific heat, and thermal conductivity of GNNF, were measured to evaluate the feasibility of GNNF application in heat exchange. Finally, GNNF was applied to the water-cooled system of the central processing unit (CPU) to conduct heat dissipation performance experiments in order to evaluate the heat exchange performance of GNNF. The experimental parameters of the heat dissipation performance experiment are four GNNF concentrations (0, 0.05, 0.1, and 0.2 wt%), three heating powers (50, 100, 150 W), and three flow rates (2, 3.5, and 5 LPM). The results show that when the ambient temperature is at 25°C, the concentration of GNNF with the best heat dissipation capacity is 0.05 wt%, having the highest increasing ratio of heat exchange under the parameters of high flow rate and low heating power. The increasing heat exchange ratio for 0.05 wt% GNNF at 50 W/5 LPM is about 13.9% higher than that of water. At an ambient temperature of 32°C, the concentration of GNNF with the best heat dissipation capability is 0.1 wt%. The increasing heat exchange ratio for 0.1 wt% GNNF at 50 W/5 LPM is about 63.1% higher than that of water. Further, 0.05 wt% and 0.1 wt% GNNF can improve the system efficiency constant (SEF) by 18.2% and 59.1% at the ambient temperature of 25°C and 32°C, respectively.