Material Compatibility for Passive Two-Phase Immersion Cooling Applications
Type of Degreethesis
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The objective of this work was to investigate potential material compatibility issues related to immersion cooling for high performance computing applications. Extended exposure of potential performance computing components and fluid handling materials to 3M’s NovecTM 649, NovecTM HFE-7100, and FluorinertTM FC-72 engineered fluids was simulated using a Soxhlet extractor. This accelerated testing led to chemical elution from some polymeric materials into the fluid. In most cases, the fluid contaminants were polymer additives, particularly plasticizers. The contaminants were identified using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy as well as gas chromatography/mass spectrometry (GC/MS). The total contaminant concentrations were determined using mass balances. In addition, an ultraviolet-visible spectroscopy (UV-Vis) calibration curve was developed to measure the concentration of dioctyl phthalate (DOP) extracted from poly(vinyl chloride) (PVC) into the fluids. UV-Vis was also used to show the amount of DOP that could be removed from the fluid using consumer grade activated carbon. The use of fundamental thermodynamic relationships for selection of compatible materials with dielectric fluids was also explored. Additional thermodynamic modeling research would enable formulation and/or selection of materials with improved compatibility. Meanwhile, the empirical data has resulted in material selection guidelines for passive two-phase immersion cooling using the engineered dielectric fluids.