{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:45:27Z","timestamp":1760060727210,"version":"build-2065373602"},"reference-count":31,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2025,9,16]],"date-time":"2025-09-16T00:00:00Z","timestamp":1757980800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia (FCT)","award":["PTDC\/EMETED\/7801\/2020","UIPD\/50009\/2020-FCT","UIDB\/50009-FCT","CEECINST\/00043\/2021\/CP2797\/CT0005","LA\/P\/0083\/2020 IN +-IST-ID"],"award-info":[{"award-number":["PTDC\/EMETED\/7801\/2020","UIPD\/50009\/2020-FCT","UIDB\/50009-FCT","CEECINST\/00043\/2021\/CP2797\/CT0005","LA\/P\/0083\/2020 IN +-IST-ID"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Energies"],"abstract":"<jats:p>This study addresses the characterization of two-phase flow phenomena in a microchannel heat sink designed to cool high-concentration photovoltaic cells. Two-phase flows can introduce instabilities that affect heat exchange efficiency, a challenge intensified by the small dimensions of microchannels. A single polydimethylsiloxane (PDMS) microchannel was fixed on a stainless steel sheet, heated by the Joule effect, which was cooled by the working fluid HFE 7100 as it undergoes phase change. Experiments were performed using two microchannel widths with a fixed height and length, testing two heat fluxes and three values of the Reynolds number, within the laminar flow regime. Temperature and pressure drop data were collected alongside high-speed and time- and space-resolved thermal images, enabling the observation of flow boiling patterns and the identification of instabilities. Enhanced surfaces with microcavities depict a positive effect of a regular pattern of microcavities on the surface, increasing the heat transfer coefficient by 34\u2013279% and promoting a more stable flow with decreased pressure losses.<\/jats:p>","DOI":"10.3390\/en18184915","type":"journal-article","created":{"date-parts":[[2025,9,16]],"date-time":"2025-09-16T08:56:46Z","timestamp":1758013006000},"page":"4915","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Flow Boiling in Microchannels Coupled with Surfaces Structured with Microcavities"],"prefix":"10.3390","volume":"18","author":[{"given":"Pedro","family":"Pontes","sequence":"first","affiliation":[{"name":"IN+ Center for Innovation, Technology and Policy Research, Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal"}]},{"given":"Vicente","family":"Andrade","sequence":"additional","affiliation":[{"name":"IN+ Center for Innovation, Technology and Policy Research, Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal"}]},{"given":"Mariana","family":"Perez","sequence":"additional","affiliation":[{"name":"IN+ Center for Innovation, Technology and Policy Research, Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9801-7617","authenticated-orcid":false,"given":"Ana S.","family":"Moita","sequence":"additional","affiliation":[{"name":"IN+ Center for Innovation, Technology and Policy Research, Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2025,9,16]]},"reference":[{"key":"ref_1","unstructured":"N. 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