Influence of height difference on thermal performance and flow stability of loop thermosyphon equipped with vertically placed flat evaporator for IGBT module cooling

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences Pub Date : 2025-07-02 DOI:10.1016/j.ijthermalsci.2025.110124

Hengxuan Xu , Xiangji Guo , Shaowei Yang , Fengyi Tang , Bo Zhang , Kang Wang

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引用次数: 0

Abstract

This study presents a comprehensive experimental investigation into the thermal-hydraulic performance and flow dynamics of a loop thermosyphon system incorporating a vertically oriented flat evaporator designed for insulated gate bipolar transistor (IGBT) module cooling. The effects of critical operational parameters, namely liquid filling ratio (31 %–92 %), heat load (100–900 W), and height difference between evaporator and condenser (0 cm, 20 cm, 40 cm, and 60 cm), on heat transfer characteristics, temperature uniformity, and start-up behavior were systematically examined. Results reveal that increasing the height difference enhances the gravitational driving force, thereby expanding the operational heat load range and reducing the average evaporator temperature; however, it concurrently exacerbates temperature non-uniformity due to complex two-phase flow instabilities. Notably, an optimal filling ratio near 73 % was identified at zero height difference, where the system exhibits heightened sensitivity to filling variations and limited natural circulation capability. Detailed pressure measurements elucidate the interplay between liquid column height and flow resistance, highlighting a saturation phenomenon in driving pressure at elevated heat loads. The study further uncovers transient gas blockage during start-up, manifesting as short-lived dry-up and temperature oscillations, which detrimentally affect system stability. These phenomena are attributed to the coupled effects of liquid film dynamics, bubble behavior, and gravitational forces within the confined geometry of the flat evaporator. The findings provide critical insights into the underlying physical mechanisms governing loop thermosyphon operation with flat evaporators and offer practical guidelines for optimizing design parameters to achieve enhanced thermal management of high-power electronic devices.

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高差对IGBT模块垂直平板蒸发器环形热虹吸管散热性能及流动稳定性的影响

本研究提出了一个综合实验研究热虹吸系统的热工性能和流动动力学，该系统包含一个垂直定向的平板蒸发器，设计用于绝缘栅双极晶体管（IGBT）模块冷却。系统考察了关键运行参数，即充液比（31% - 92%）、热负荷（100-900 W）以及蒸发器与冷凝器之间的高度差（0 cm、20 cm、40 cm和60 cm）对传热特性、温度均匀性和启动行为的影响。结果表明：增大高度差增大了重力驱动力，从而扩大了运行热负荷范围，降低了蒸发器平均温度；然而，由于复杂的两相流不稳定性，同时加剧了温度的不均匀性。值得注意的是，在高度差为零的情况下，系统对填充变化和有限的自然循环能力表现出更高的敏感性，最佳填充率接近73%。详细的压力测量阐明了液柱高度和流动阻力之间的相互作用，突出了在高热负荷下驱动压力的饱和现象。该研究进一步揭示了启动过程中的瞬态气阻，表现为短暂的干化和温度振荡，对系统稳定性产生不利影响。这些现象归因于液膜动力学、气泡行为和重力在平板蒸发器受限几何结构中的耦合效应。该研究结果为控制扁平蒸发器循环热虹吸运行的潜在物理机制提供了重要见解，并为优化设计参数以实现高功率电子设备的增强热管理提供了实用指南。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal of Thermal Sciences 工程技术-工程：机械

CiteScore

8.10

自引率

11.10%

发文量

531

审稿时长

55 days

期刊介绍： The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review. The fundamental subjects considered within the scope of the journal are: * Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow * Forced, natural or mixed convection in reactive or non-reactive media * Single or multi–phase fluid flow with or without phase change * Near–and far–field radiative heat transfer * Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...) * Multiscale modelling The applied research topics include: * Heat exchangers, heat pipes, cooling processes * Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries) * Nano–and micro–technology for energy, space, biosystems and devices * Heat transport analysis in advanced systems * Impact of energy–related processes on environment, and emerging energy systems The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.