Year: 2025
Type: article
Abstract: 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 34–279% and promoting a more stable flow with decreased pressure losses.
Source: Energies
DOI: 10.3390/en18184915
Authors: Pedro Pontes, Vicente Andrade, Mariana Perez, Ana S. Moita
Institutions: University of Lisbon, Instituto Superior Técnico
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,137
OpenAlex ID: W4414249237