{"title":"Straight ultra-thin vapor chambers tested under different modes for different vapor duct thicknesses","authors":"","doi":"10.1016/j.applthermaleng.2024.124353","DOIUrl":null,"url":null,"abstract":"<div><p>This study aims to demonstrate, through careful temperature measurements and infrared images, that tests for a vapor chamber (VC) under a VC mode or a heat pipe (HP) mode, reach very different thermal performances due to different severities for water accumulation at the condenser end. Both modes have been frequently adopted in the literature with the difference overlooked. Experiments are conducted for 100 × 20 mm<sup>2</sup> straight ultra-thin vapor chambers (UTVCs) with a 0.17 mm or a 0.12 mm vapor duct thickness and a total thickness of 0.45 mm or 0.4 mm, respectively. Three different charges, an over-charge, a charge with the charge ratio slightly larger than 1.0, and an under-charge, are prepared for each vapor duct thickness. Severe water accumulation over the condenser is observed under the HP mode, yielding drastic temperature drops therein. Under the HP mode the maximum heat transfer rate (<em>Q</em><sub>max</sub>) drops to about only 3–4 W with vapor duct thickness (<em>h</em>) = 0.17 mm and fails at actual vapor input ∼3 W with <em>h</em> = 0.12 mm. Water accumulation cannot be totally removed in the HP mode when the UTVC is placed vertically, although slight improvement on the thermal performance can be achieved with the assistance of gravity. Under a HP mode, the minimum vapor chamber resistance (<em>R</em><sub>min</sub>) ranges between 0.7–1.0 K/W, while under a VC mode <em>R</em><sub>min</sub> is 0.14–0.29 K/W. <em>Q</em><sub>max</sub> appears slightly reduced for the thinner vapor duct thickness due to the larger vapor resistance.</p></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":6.1000,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Applied Thermal Engineering","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1359431124020210","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
引用次数: 0
Abstract
This study aims to demonstrate, through careful temperature measurements and infrared images, that tests for a vapor chamber (VC) under a VC mode or a heat pipe (HP) mode, reach very different thermal performances due to different severities for water accumulation at the condenser end. Both modes have been frequently adopted in the literature with the difference overlooked. Experiments are conducted for 100 × 20 mm2 straight ultra-thin vapor chambers (UTVCs) with a 0.17 mm or a 0.12 mm vapor duct thickness and a total thickness of 0.45 mm or 0.4 mm, respectively. Three different charges, an over-charge, a charge with the charge ratio slightly larger than 1.0, and an under-charge, are prepared for each vapor duct thickness. Severe water accumulation over the condenser is observed under the HP mode, yielding drastic temperature drops therein. Under the HP mode the maximum heat transfer rate (Qmax) drops to about only 3–4 W with vapor duct thickness (h) = 0.17 mm and fails at actual vapor input ∼3 W with h = 0.12 mm. Water accumulation cannot be totally removed in the HP mode when the UTVC is placed vertically, although slight improvement on the thermal performance can be achieved with the assistance of gravity. Under a HP mode, the minimum vapor chamber resistance (Rmin) ranges between 0.7–1.0 K/W, while under a VC mode Rmin is 0.14–0.29 K/W. Qmax appears slightly reduced for the thinner vapor duct thickness due to the larger vapor resistance.
期刊介绍:
Applied Thermal Engineering disseminates novel research related to the design, development and demonstration of components, devices, equipment, technologies and systems involving thermal processes for the production, storage, utilization and conservation of energy, with a focus on engineering application.
The journal publishes high-quality and high-impact Original Research Articles, Review Articles, Short Communications and Letters to the Editor on cutting-edge innovations in research, and recent advances or issues of interest to the thermal engineering community.