Experimental Study on the Starting-Up and Heat Transfer Characteristics of a Pulsating Heat Pipe under Local Low-Frequency Vibrations

Jing Chen,Junbiao Dong,Ye Yao

doi:10.3390/en14196310

Jing Chen, Junbiao Dong + Show 1 more

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https://doi.org/10.3390/en14196310

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Abstract

Vibrations have attracted much attention as an effective method for enhancing heat transfer in pulsating heat pipes (PHPs). This study mainly investigates and explores the effects of local low-frequency vibrations on the starting-up and heat transfer characteristics of a PHP. The starting-up temperature and average temperatures along the evaporation section of the pulsating heat pipe were experimentally scrutinized, along with thermal performance, under local vibrations on evaporation, condensation and adiabatic sections, respectively. The following important conclusions can be derived by the experimental study: (1) The effect of vibrations at the evaporation section and at the adiabatic section during the starting-up time of the PHP were more significant than that at the condensation section; (2) vibrations at different positions could reduce the starting-up temperature of the PHP—the effect of the vibrations at the evaporation section was the best when heat power was lower, while the effect of vibrations on the adiabatic section was the best when heat power was higher; (3) vibrations at the evaporation and adiabatic sections could reduce the thermal resistance of the PHP, but vibrations at the condensation section had little effect on the thermal resistance of the PHP; (4) vibrations at the evaporation and adiabatic sections could effectively reduce the temperature at the evaporation section of the PHP, but the vibrations at the condensation section had no effect on the temperature at the evaporation section of the PHP. This paper shows that local low-frequency vibrations have positive effects on the heat transfer performances of PHPs.

Highlights

A heat pipe, known as a “thermal superconducting tube”, is a heat transfer technology developed in the 1960s
This is because most of the heat during ferent vibration positions in the case of a 40 W heating power
This is because most of the heat while the pulsating heat pipes (PHPs) under the non-vibration condition started later, showing that vibrations during the preheating process comes from heating wire, and the heat generated by vibrashorten the preheating time of the PHP and accelerate the start

Summary

Introduction

A heat pipe, known as a “thermal superconducting tube”, is a heat transfer technology developed in the 1960s. It adopts vaporization and condensation phase transformation of its internal saturated working medium to realize heat transfer. This phase transformation heat transfer mode has a very high heat transfer capacity. Aluminum and other metals with good heat conductivity, the heat transfer capacity of a heat pipe is several orders of magnitude higher [1]. Mahajan et al [3]

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