Thermal evaluation of self-rewetting fluids in server-grade heat pipes

This study investigates the feasibility of using self-rewetting fluids (SRWFs) in server-grade heat pipes with bent and flattened geometries, common in air-cooled thermal modules for data centers. Conventional fluids like water often face performance limitations at high heat loads, prompting interes...

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Main Authors: Ya-Lin Hsiao, Chen-li Sun
Format: Article
Language:English
Published: Elsevier 2025-10-01
Series:Case Studies in Thermal Engineering
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2214157X2501010X
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author Ya-Lin Hsiao
Chen-li Sun
author_facet Ya-Lin Hsiao
Chen-li Sun
author_sort Ya-Lin Hsiao
collection DOAJ
description This study investigates the feasibility of using self-rewetting fluids (SRWFs) in server-grade heat pipes with bent and flattened geometries, common in air-cooled thermal modules for data centers. Conventional fluids like water often face performance limitations at high heat loads, prompting interest in SRWFs that leverage inverse Marangoni convection for improved thermal performance. We experimentally tested aqueous solutions of 2-butanol (2–6 wt%), heptanol (0.05–0.1 wt%), and octanol (0.03 wt%). A 2–4 wt% 2-butanol solution achieved the highest cooling capacity, up to 70 W, a 9.1–27.3 % improvement over water. At 60–70 W, strong inverse Marangoni flow promoted effective liquid return to the evaporator, lowering the overall thermal resistance to 0.32–0.35 °C W−1. However, excessive concentrations (6 wt%) led to higher phase-change resistance and condenser flooding. Dilute heptanol and octanol solutions reduced overall thermal resistance by up to 14.9 % at moderate heat loads (30–50 W), benefiting from lower threshold temperatures for self-rewetting behavior. Optimal performance was observed at a 50° inclination, where both gravity and inverse Marangoni effects contribute synergistically. These findings highlight the importance of tailoring SRWF type and concentration to specific cooling demands and demonstrate the potential of SRWFs for improving performance, reliability, and design flexibility in commercial server cooling applications.
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spelling doaj-art-a448d02a51ca4f62bada93d3064035ba2025-08-20T02:46:40ZengElsevierCase Studies in Thermal Engineering2214-157X2025-10-017410675010.1016/j.csite.2025.106750Thermal evaluation of self-rewetting fluids in server-grade heat pipesYa-Lin Hsiao0Chen-li Sun1Department of Mechanical Engineering, National Taiwan University, 1 Section 4 Roosevelt Road, Taipei, 106319, Taiwan; Taiwan Google Infrastructure Co., Ltd., 73F-1 7 Section 5 Xinyi Road, Taipei, 110615, TaiwanDepartment of Mechanical Engineering, National Taiwan University, 1 Section 4 Roosevelt Road, Taipei, 106319, Taiwan; Corresponding author.This study investigates the feasibility of using self-rewetting fluids (SRWFs) in server-grade heat pipes with bent and flattened geometries, common in air-cooled thermal modules for data centers. Conventional fluids like water often face performance limitations at high heat loads, prompting interest in SRWFs that leverage inverse Marangoni convection for improved thermal performance. We experimentally tested aqueous solutions of 2-butanol (2–6 wt%), heptanol (0.05–0.1 wt%), and octanol (0.03 wt%). A 2–4 wt% 2-butanol solution achieved the highest cooling capacity, up to 70 W, a 9.1–27.3 % improvement over water. At 60–70 W, strong inverse Marangoni flow promoted effective liquid return to the evaporator, lowering the overall thermal resistance to 0.32–0.35 °C W−1. However, excessive concentrations (6 wt%) led to higher phase-change resistance and condenser flooding. Dilute heptanol and octanol solutions reduced overall thermal resistance by up to 14.9 % at moderate heat loads (30–50 W), benefiting from lower threshold temperatures for self-rewetting behavior. Optimal performance was observed at a 50° inclination, where both gravity and inverse Marangoni effects contribute synergistically. These findings highlight the importance of tailoring SRWF type and concentration to specific cooling demands and demonstrate the potential of SRWFs for improving performance, reliability, and design flexibility in commercial server cooling applications.http://www.sciencedirect.com/science/article/pii/S2214157X2501010XInverse Marangoni effectSelf-rewetting fluids (SRWFs)Heat pipesServer coolingThermal management
spellingShingle Ya-Lin Hsiao
Chen-li Sun
Thermal evaluation of self-rewetting fluids in server-grade heat pipes
Case Studies in Thermal Engineering
Inverse Marangoni effect
Self-rewetting fluids (SRWFs)
Heat pipes
Server cooling
Thermal management
title Thermal evaluation of self-rewetting fluids in server-grade heat pipes
title_full Thermal evaluation of self-rewetting fluids in server-grade heat pipes
title_fullStr Thermal evaluation of self-rewetting fluids in server-grade heat pipes
title_full_unstemmed Thermal evaluation of self-rewetting fluids in server-grade heat pipes
title_short Thermal evaluation of self-rewetting fluids in server-grade heat pipes
title_sort thermal evaluation of self rewetting fluids in server grade heat pipes
topic Inverse Marangoni effect
Self-rewetting fluids (SRWFs)
Heat pipes
Server cooling
Thermal management
url http://www.sciencedirect.com/science/article/pii/S2214157X2501010X
work_keys_str_mv AT yalinhsiao thermalevaluationofselfrewettingfluidsinservergradeheatpipes
AT chenlisun thermalevaluationofselfrewettingfluidsinservergradeheatpipes