Open Access

ARTICLE

LOW-ORDER MODEL OF THE DYNAMICS AND START-UP OF A PULSATING HEAT PIPE

Felix Schily^a,∗, Wolfgang Polifke^a

a Technical University of Munich, 85748 Garching, Germany
∗ Corresponding author. Email: schily@tfd.mw.tum.de

Frontiers in Heat and Mass Transfer 2021, 17, 1-15. https://doi.org/10.5098/hmt.17.16

Abstract

A simple open-loop pulsating heat pipe model is proposed, which allows to analytically determine the start-up behavior by a linear stability analysis. Two distinct types of instability can occur in such a pulsating heat pipe: oscillatory and non-oscillatory. This paper demonstrates that for bubbles consisting of non-condensible gas, large temperature gradients along the wall are required to achieve start-up, whereas start-up is fairly easy to achieve when there is only a single working medium that forms bubbles from its vapor. The study also finds that surface tension as such only influences start-up indirectly, while contact angle hysteresis dampens out any instabilities.

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