Nucleate Boiling in Large Arrays of Impinging Water Sprays

• Published in: Heat transfer engineering Vol. 34; no. 5-6; pp. 479 - 491
• Main Authors: Pereira, Ricardo Hernandez, Filho, Enio Pedone Bandarra, Braga, Sergio Leal, Parise, José Alberto Reis
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Philadelphia, PA Taylor & Francis Group 01.01.2013; Taylor & Francis; Taylor & Francis Ltd
• Subjects: Applied sciences; Arrays; Coolants; Cooling; Correlation analysis; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Heat flux; Heat transfer; Nucleate boiling; Sprayers; Sprays; Temperature; Theoretical studies. Data and constants. Metering; Array; Tuyere; Heating surface; Test facility; Interaction; Spray cooling; Geometrical configuration; Nucleate boiling; Critical heat flow; Experimental study; Heat transfer
• ISSN: 0145-7632; 1521-0537
• DOI: 10.1080/01457632.2012.722443

The nucleate boiling of subcooled water, under 100 cm 2 square arrays of impinging sprays, was experimentally investigated. Three types of commercially available full cone pressure nozzles, of distinct flow capacities, allowed for runs where the average impinging coolant mass flux spanned the 0.3-7.2 kg/m 2 -s range. Array geometry was varied adjusting nozzle-to-nozzle and nozzle-to-impingement surface distances. Experimental construction allowed for good drainage of spent coolant and unrestricted air entrainment to spray cones. The average heat flux through the heated, upward-facing, copper impingement surface was found to be equal to the sum of single-phase and nucleate boiling heat flux components. The phase-change component was experimentally observed to depend upon wall excess temperature only. The proposed heat transfer correlation reproduces original experimental data with a mean absolute error of 10.6%. Non-critical-heat-flux (non-CHF) cooling capacity and efficiencies of up to, respectively, 2000 kJ/kg and 83% were observed.