Topic: Advanced Nanofluids for Energy Efficiency and Storage

Speaker: Dr. Dileep Singh, Argonne National Laboratory,USA.

Abstract：

Nanofluids or liquids in which nanoscale particles are uniformly dispersed, have the potential for enhanced thermal performance. In this presentation, we report the properties of nanofluids (with SiC and alumina nanoparticles) prepared in a widely used heat transfer fluid for cooling in transportation and power electronics: ethylene glycol (EG) and water (H2O) mixture with a 50/50 volume ratio. Particles of SiC with varying sizes (16-90 nm) have been investigated. Mean sizes of nanoarticles were determined using BET gas absorption technique. Effects of viscosity of the nanofluids with temperature and particle loadings were established. Thermal conductivity of the fluid was measured as a function of the particle sizes at a nominal nanoparticle loadings of 1-4 vol.%. Enhancements in thermal conductivities for the nanofluids with varying nanoparticle loadings were maintained at elevated temperatures. Results of thermal conductivity have been rationalized based on the existing theories of heat transfer in fluids.

Heat transfer measurements as a function of fluid velocity indicated a dependence on the particle size. Thermal conductivity and heat transfer enhancements as a function of particles sizes is rationalized based on the interfacial resistance between the particle and the fluid. Mechanical effects such as erosion and fouling from nanofluid mixtures were also investigated.

Criteria to evaluate the efficiencies of the nanofluids in various flow conditions were applied to establish the performance of the nanofluid for an engineering application. Overall efficiency of nanofluids and its implications for engineering cooling applications will be presented. Finally,role of using functional nanoparticles in enhancing the thermo-physical properties of high temperature heat transfer fluids and thermal energy storage for concentrated solar powerapplicationwill be discussed.