ISSN Online: 2379-1748
ISBN Flash Drive: 978-1-56700-469-4
ISBN Online: 978-1-56700-470-0
Second Thermal and Fluids Engineering Conference
DNS STUDY ON HEAT TRANSFER OF VISCOELASTIC FORCED HOMOGENEOUS ISOTROPIC TURBULENT FLOWS
要約
In order to have an insight into turbulent heat transfer reduction (HTR) mechanism by additives, quasi-steady heat transfer phenomena driven by a uniform temperature gradient were simulated based on direct numerical simulations (DNS) of viscoelastic forced homogeneous isotropic turbulent flows for the first time. Heat transfer characteristics were explored from statistic viewpoint. It was found that viscoelastic additives depress thermal fluctuations and turbulent heat flux, decrease heat transfer efficiency, increase intermittency of thermal fluctuations and make thermal fluctuations more orderly. Heat transfer reduction mechanism was deeply investigated from multi-scale viewpoint. It was concluded that viscoelastic additives modify turbulent structures and propel turbulent fluctuation to transfer heat against temperature gradient, which causes the heat transfer reduction phenomenon.