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Investigation and visualization of surfactant effect on flow pattern and performance of pulsating heat pipe

Gandomkar, A ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1007/s10973-019-08649-z
  3. Publisher: Springer Netherlands , 2020
  4. Abstract:
  5. Pulsating heat pipes (PHPs) are one of the new devices used for cooling in several applications such as electronic and aerospace systems. Their low cost, effectiveness at various conditions, being equipped for passive energy conversion, and well distribution of temperature compared to conventional heat pipes are among the reasons of their popularity. To investigate the effect of surface tension of the working fluid on the behavior of PHPs, a copper heat pipe is fabricated with inner and outer diameters of 2 mm and 4 mm, respectively. Five different concentrations of cetrimonium bromide (C-Tab) surfactant are dissolved in water and are tested with a filling ratio of 50% (± 1%). A piece of glass is placed in the adiabatic section to make the flow visualizations possible. Thermal resistance and flow visualization results are compared. Visualization of the flow shows that by increasing the surfactant concentration, annular and semi-annular regimes can be observed at lower powers. It is also detected that by increasing the surfactant concentration, thermal resistance will decrease, while the maximum heat flux is reduced. This can be explained by thinner film thickness in the evaporator. The lowest thermal resistance was detected to be 0.44 K/W for the 0.25 g L−1 C-Tab concentration at 25 W heat input power which shows a significant improve of 77.5% compared to pure water at the same power. © 2019, Akadémiai Kiadó, Budapest, Hungary
  6. Keywords:
  7. Flow regime ; PHP ; Surface tension ; Surfactant ; Thermal resistance ; Visualization ; Cooling systems ; Electronic cooling ; Energy conversion ; Flow patterns ; Heat flux ; Heat pipes ; Heat resistance ; Surface active agents ; Surface tension ; Aerospace systems ; Distribution of temperature ; Flow regimes ; Maximum heat flux ; Pulsating heat pipe ; Surfactant concentrations ; Surfactant effects ; Visualization results ; Flow visualization
  8. Source: Journal of Thermal Analysis and Calorimetry ; Volume 139, Issue 3 , 2020 , Pages 2099-2107
  9. URL: https://link.springer.com/article/10.1007/s10973-019-08649-z