A new approach is proposed for studying the effect of fluid motion on heat transfer. Special attention is given to the details of the time-dependent structure of large-scale turbulence and the associated interactions with surfaces. The results will be important in many industrial engineering situations, for example, combustors, electronic cooling devices, gas turbine engines, building structures, and heat exchangers. The innovative approach combines time-resolved visualization of the fluid flow with simultaneous measurements of the surface heat flux. A new type of microscale sensor array will be developed for the heat flux measurements using thin-film fabrication processes. The experiments will be used to validate a simple physical model based on the coherent structure of the flow and its interaction with the surface. So far, the model has successfully predicted the overall increase in the heat transfer due to large-scale freestream turbulence in several different geometries for both low and high speed flows. Although the approach is novel and risky, if proven successful, the impact of the results will be far reaching and will broadly extend our understanding of the effects of turbulence on heat transfer. The broader impacts of the proposed research include the diverse group of the graduate students who will be trained in state-of-the-art experimental techniques, the education of a large number of undergraduate mechanical engineering students (over 200 per year will be impacted), and the interactions with other engineers and scientists. The microscale sensor arrays developed will be shared with industry and labs around the world. If successful, the leap in understanding of turbulent heat transfer will be shared with researchers and practitioners of heat transfer in many fields of engineering from the mega scales of atmospheric turbulence to the micro scales of electronic cooling. The benefits to society will be derived from the improved utilization and control of energy in many products and processes. This award has been funded by the Thermal Transport and Thermal Processing Program of the Chemical and Transport Systems Division.
