Gravitational effects on electroosmotic flow in micro heat pipes

Fun Liang Chang, Yew Mun Hung

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    Purpose: This paper aims to investigate the coupled effects of electrohydrodynamic and gravity forces on the circulation effectiveness of working fluid in an inclined micro heat pipe driven by electroosmotic flow. The effects of the three competing forces, namely, the capillary, the gravitational and the electrohydrodyanamic forces, on the circulation effectiveness of a micro heat pipe are compared and delineated. Design/methodology/approach: The numerical model is developed based on the conservations of mass, momentum and energy with the incorporation of the Young–Laplace equation for electroosmotic flow in an inclined micro heat pipe incorporating the gravity effects. Findings: By inducing electroosmotic flow in a micro heat pipe, a significant increase in heat transport capacity can be attained at a reasonably low applied voltage, leading to a small temperature drop and a high thermal conductance. However, the favorably applied gravity forces pull the liquid toward the evaporator section where the onset of flooding occurs within the condenser section, generating a throat that shrinks the vapor flow passage and may lead to a complete failure on the operation of micro heat pipe. Therefore, the balance between the electrohydrodyanamic and the gravitational forces is of vital importance. Originality/value: This study provides a detailed insight into the gravitational and electroosmotic effects on the thermal performance of an inclined micro heat pipe driven by electroosmotic flow and paves the way for the feasible practical application of electrohydrodynamic forces in a micro-scale two-phase cooling device.

    Original languageEnglish
    Pages (from-to)535-556
    Number of pages22
    JournalInternational Journal of Numerical Methods for Heat and Fluid Flow
    Volume30
    Issue number2
    DOIs
    Publication statusPublished - 16 Jan 2020

    Keywords

    • Circulation effectiveness
    • Electrohydrodynamic
    • Electroosmotic flow
    • Gravity force
    • Micro heat pipe

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