Characteristics of flow behavior and heat transfer in the grooved channel for pulsatile flow with a reverse flow
| Autor: | Fengge Zhang, Yongning Bian, Hirofumi Arima, Yang Yunjie, Junxiu Pan, Yang Liu |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Fluid Flow and Transfer Processes
Materials science Mechanical Engineering Heat transfer enhancement Pulsatile flow Reynolds number 02 engineering and technology Mechanics Vorticity 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Nusselt number 010305 fluids & plasmas Physics::Fluid Dynamics symbols.namesake 0103 physical sciences Heat transfer symbols Strouhal number Streamlines streaklines and pathlines 0210 nano-technology |
| Zdroj: | International Journal of Heat and Mass Transfer. 147:118932 |
| ISSN: | 0017-9310 |
| DOI: | 10.1016/j.ijheatmasstransfer.2019.118932 |
| Popis: | The present study investigates the flow behavior and heat transfer in the grooved channel for pulsatile flow with a reverse flow by experimental and numerical approaches at different Strouhal numbers (from 0 to 0.125) and different oscillatory fractions (from 0.6 to 1.4). The pulsatile flow patterns are visualized by the aluminum dust method, and the numerical model is validated by experimental results. It is observed that the flow is less stable in the reverse acceleration phase. At the same time, streamlines, temperature and vorticity in the upper and lower grooves are asymmetrical. Besides, this instability leads to a remarkable mix between the groove and the main flow and contributes to the enhancement of heat transfer. In addition, the onset of the unstable state gradually delays and the duration of the unstable state reduces with the increase of Strouhal number during the test range when the net Reynolds number is 375 and the oscillatory fraction is 1.4. Also, it demonstrates that the time-averaged Nusselt number increases with oscillatory fraction which suggests that the imposed reverse flow is capable of improving the heat transfer. It is further revealed that the maximum heat transfer enhancement factor is 2.74 when the oscillatory fraction is 1.4. |
| Databáze: | OpenAIRE |
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