LAUSR

Abstract In quench subcooled-jet boiling, an effective cooling of large surface area is achieved with jet arrays. Here a stainless-steel plate initially superheated at 900 °C is cooled with seven hexagonally arranged water [1 atm, 20 °C (80 °C subcooling)] jets (7j), and with varying jet separation distance (with a jet Reynolds number ReD = 5000). Using high-definition visualization synchronized with the surface thermal characterization based on the inverse-conduction analysis allows calculation of the spatial and temporal variations of the local and average heat flux (q) and heat transfer coefficient (h). The local and temporal peaks in q and h occur under the jets with enhancements in the regions of their interactions. We compare these results with the prior two jets (2j) and single jet (1j) results (with ReD = 15,000). For a jet separation of four nozzle diameter (S/Dn = 4), the 7j behavior is close to the single jet (1j), while with larger separation extra h peaks occur and the cooling becomes more effective (larger cooling area, but with smaller area-averaged heat transfer coefficient 〈h〉). For S/Dn = 10, the 7j enhanced cooling effectiveness is smaller than the 2j effectiveness, suggesting using similar total liquid flow rate, fewer jets are preferred. The cooling effectiveness enhancement for the S/Dn = 6 arrangement is the highest, reaching 50% and covering a large high-h area, and over a long elapsed time.