Study On The Stability And Thermal Properties Of Propylene Glycol-based MWCNT Nanofluid

Nanofluid enhances heat transfer efficiency and effectively addresses the challenge of resource efficiency,playing a crucial role in maximizing resource utilization and implementing the dual carbon plan.Propylene glycol,a green and widely employed heat transfer agent,has gained significant attention.However,its low thermal conductivity hampers its progress.Introducing nanoparticles offers a feasible solution to overcome this limitation.This study primarily investigates the stability factors and thermal properties of propylene glycol-based nanofluid containing multi-walled carbon nanotubes(MWCNTs).This study assessed the stability of propylene glycol-based MWCNT nanofluids using six different dispersants,employing gravitational sedimentation and UV spectrophotometry.The results indicated that PVP exhibited superior effectiveness in enhancing nanofluid stability.The impact of each factor on absorbance was determined using the BBD(Box-Behnken Design)model for response surface optimization.The SN ratio and MWCNT concentration significantly influenced absorbance,while the experimental range of ultrasonic treatment time(2-3h)had no notable effect.Optimal conditions for preparing propylene glycol-based MWCNT nanofluids were identified.The results were analyzed through analysis of variance(ANOVA)and validated experimentally.The findings demonstrated that the BBD model accurately predicted the stability of propylene glycol-based MWCNT nanofluid,providing a reference for further exploration of its thermal properties.We examined the viscosity of the nanofluid using a capillary viscometer.The findings revealed that PVP had a greater impact on nanofluid viscosity compared to CTAB.Additionally,the viscosity of propylene glycol-based MWCNT nanofluid decreased as the temperature increased,while it increased with a higher SN ratio.We used a surface tension meter to examine the surface tension of propylene glycol-based MWCNT nanofluid.The results indicated that the surface tension decreased as the temperature increased.Furthermore,the addition of nanoparticles led to a reduction in surface tension,which further decreased with higher nanoparticle concentrations.Additionally,the surface tension decreased with an increase in the SN ratio.We examined the changes in thermal conductivity of propylene glycol-based MWCNT nanofluid.The results indicated that the influence of temperature variation on the thermal conductivity of the nanofluid was minimal.However,the addition of surfactant enhanced the thermal conductivity.Furthermore,incorporating MWCNT nanoparticles into propylene glycol-based fluids was more effective in improving thermal conductivity compared to using spherical nanoparticles.Additionally,propylene glycol-based MWCNT nanofluids exhibited higher thermal conductivity at lower temperatures.