Numerical investigation of the effects of orientation and gravity in a closed loop pulsating heat pipe

Mauro Mameli, Marco Marengo, Stefano Zinna

Research output: Contribution to journalArticle

Abstract

The Closed Loop Pulsating Heat Pipe (CLPHP) is a very promising passive two-phase heat transfer device for relatively high heat fluxes (up to 30 W/cm 2) patented by Akachi (1990, 1993). Although the CLPHP has a simple structure, its working principles are very complex compared to the standard heat pipe with a porous wick. One of the most debated issues deals on how the thermal performance is affected by the inclination and by the action of different gravity fields (terrestrial, lunar, martian and microgravity). Even if the internal tube diameter satisfies the conventional slug flow regime requirement on the Bond number, gravity force still plays an important role on the PHP behaviour. Heat input and the number of turns are two of the most important indirect parameters linked to the gravity issue. A complete numerical campaign has been performed by means of a FORTRAN code at different inclination angles and gravity levels on various PHP. The numerical model is able to estimate both the hydrodynamic and the thermal performance of a CLPHP with different working fluids. The analysis shows that the effect of local pressure losses due to bends is important and must be taken into account, in particular in the horizontal operation which is the reference point for space applications. Numerical results are matched with the experimental data quoted in literature and both good qualitative and quantitative agreement have been found.

Original languageEnglish
Pages (from-to)79-92
Number of pages14
JournalMicrogravity Science and Technology
Volume24
Issue number2
DOIs
Publication statusPublished - 1 Mar 2012

Keywords

  • Numerical simulation
  • Passive device
  • Slug flow

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