Pool boiling heat transfer characteristics of a stepped microchannel structured heating surface. (March 2023)

• Record Type: Journal Article
• Authors: Ranjan, Atul; Priy, Akash; Ahmad, Israr; Pathak, Manabendra; Khan, Mohd. Kaleem
• Is Part Of: International journal of multiphase flow. Volume 160(2023)
• Publication Date: 2023-03
• Subjects: Pool boiling -- Structured surface -- Heat transfer enhancement -- Critical heat flux -- Rewetting -- Bubble dynamics; Multiphase flow -- Periodicals; Écoulement polyphasique -- Périodiques; Multiphase flow; Periodicals; 620.1064
• DOI: 10.1016/j.ijmultiphaseflow.2022.104351
• Languages: English
• ISSNs: 0301-9322

Abstract

Highlights: A novel stepped-segmented microchannels (SSMC) structured surface is fabricated. Pool boiling heat transfer performance of SSMC structured surface is investigated. HTC and CHF enhanced by 296% and 224% respectively for SSMC structured surface. More nucleation sites and frequent rewetting enhance heat transfer in SSMC surface. Favorable bubble dynamics are responsible for better heat transfer performance. Abstract: Structured heating surfaces modify the bubble ebullition cycle in pool boiling, thereby enhancing heat transfer. The present work explores an innovative structured heating surface for heat transfer enhancement in pool boiling. Two types of microstructured, i.e., stepped microchannels (SMC) and stepped-segmented microchannels (SSMC) surfaces, have been fabricated on a heating surface, and their heat transfer characteristics are experimentally investigated. Saturated pool boiling experiments are performed with deionized water at atmospheric pressure, and the performance of both the structured surfaces is compared with a plain copper heating surface. All three heating surfaces are fabricated using a wire-EDM process with the same footprint area of 10 × 10 mm 2 . The SSMC structured surface exhibits the maximum heat transfer coefficient (HTC) and results in 296% heat transfer enhancement compared to the plain copper surface. The surface also makes a 224% enhancement in the critical heat flux (CHF) compared to the plain copper surface. Compared to the plain copper surface, the SMC structured surface shows an enhancement of 200% in HTC and 162% in CHF. For the same operating conditions, the SSMC structured surface shows better pool boiling heat transfer characteristics than the similar structured surfaces reported in the literature. More nucleation sites, better bubble evolution along the expanding cross-section stepped channel, and efficient rewetting of the heating surface contribute to the excellent thermal performance of the SSMC structured surface. Graphical abstract: Image, graphical abstract