Open Access

ARTICLE

Numerical Simulation of Heat Transfer Enhancement by Vibration of an Irregular Pipe

Riyi Lin^*, Bi Pang, Xinwei Wang
School of New Energy, China University of Petroleum (East China), No. 66 Changjiang West Road, Huangdao District, Qingdao, China
* Corresponding Author: Riyi Lin. Email:
(This article belongs to the Special Issue: Multi-Scale Heat and Mass Transfer: From Intensification to System Integration)

Frontiers in Heat and Mass Transfer https://doi.org/10.32604/fhmt.2026.076874

Received 27 November 2025; Accepted 30 January 2026; Published online 06 March 2026

Abstract

The thickening of condensed liquid film outside heat-exchange pipes and the pipe bundle effect can significantly degrade the heat transfer efficiency, thus restricting the vacuum phase-change heating furnace from achieving its rated thermal efficiency of over 90%. In this work, a heat transfer enhancement method coupling simple harmonic vibration with non-circular pipes was proposed. A CFD model describing the heat transfer process of horizontal pipes under vibratory conditions was established and stepwise validated against experimental data from published literature and the Nusselt analytical solution. Taking a 50 mm steel circular pipe as the reference, numerical simulations were performed to investigate the effects of structural parameters of oval and droplet-shaped pipes on the near-wall velocity, temperature, wall shear stress, and heat transfer coefficient under horizontal simple harmonic vibration. The results demonstrate that simple harmonic vibration can induce oblique cross-flow outside the pipes, enhance flow field disturbance, and disrupt the liquid film stability, thereby providing a crucial flow field regulation mechanism for vibration-enhanced external condensation heat transfer. An increase in the aspect ratio of droplet-shaped pipes intensifies the wall contraction effect, promotes the formation of continuous small-scale vortices near the pipe wall, and significantly improves the time-averaged heat transfer coefficient. The heat transfer performance of oval pipes is slightly superior to that of circular pipes; among them, oval pipe 2 achieves a dynamic balance between shear driving force and liquid film resistance through the synergistic matching of velocity, temperature, and viscosity, thus exhibiting the optimal wall shear stress among the oval pipe series. Under dynamic conditions, the time-averaged heat transfer coefficients of non-circular pipes are consistently higher than those of circular pipes. Moreover, the inconsistency between the heat transfer coefficient and wall shear stress distributions reveals the multi-mechanism synergy characteristics of external condensation heat transfer on non-circular pipes. This study provides core theoretical support for the engineering design of vibration-enhanced heat transfer technologies in vacuum phase-change heating furnaces.

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Keywords

Condensate film; harmonic vibration; shear force; non-circular pipe; heat transfer coefficient

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