Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
Analysis of a compact cooling system containing an enhanced-surface spray heat sink
Submission Author:
Marcus Vinícius Pedron Carneiro , SC
Co-Authors:
Marcus Vinícius Pedron Carneiro, André Provensi, Pedro Cavicchioli, Milton Pereira, Jader Riso Barbosa Jr.
Presenter: Marcus Vinícius Pedron Carneiro
doi://10.26678/ABCM.ENCIT2022.CIT22-0726
Abstract
In previous studies, we introduced the concept of a compact heat sink that combines an evaporator and an expansion device into a single unit for high heat flux applications. As the high-pressure subcooled liquid refrigerant expands in an array of oblique orifices, a spray cone is formed which directly impinges on the heated surface, removing large quantities of heat by boiling and evaporation of the liquid film. Numerous applications of the concept can be sought when one considers its integration with compact compressors (i.e., cooling of power electronics, batteries etc.), since it combines the low thermal resistance of impinging jets with below-ambient evaporating temperatures. In this paper, we evaluate the use of laser-ablated square micro pillars on the heated surface as a means to enhance the heat removal capability of the system. Microscopic and interferometric images of the resulting surfaces are presented and evaluated regarding its final topography and extended heat transfer surface area. Experiments conducted with R-134a using a two- orifice expansion device and enhanced surfaces resulted in a cooling capacity of 230 W (35.9 W/cm²) with a heated surface temperature always below 22.9°C and average heat transfer coefficients as high as 46,369 W/(m²K). In comparison with mirror polished surfaces, this represents a thermal conductance increase of 91%, resulting in a significant reduction of the heated surface temperature.
Keywords
Electronics cooling, spray cooling, Refrigeration system, enhanced surfaces
