High heat flux removal using water subcooled flow boiling in a single-side heated circular channel Ronald D. Boyd * , Marcella Strahan, Penrose Cofie, Ali Ekhlassi, Rashad Martin Thermal Science Research Center (TSRC) College of Engineering, P.O. Box 4208, Prairie View A & M University, Prairie View, TX 77446-4208, USA Received 18 June 2002; received in revised form 31 January 2003 Abstract High heat flux removal from plasma-facing components and electronic heat sinks involves conjugate heat transfer analysis of the applicable substrate and flowing fluid. For the present case of subcooled flow boiling inside a single-side heated circular channel, the dimensional results show the significant radial, circumferential and axial variations in all thermal quantities for the present radial aspect ratio (R o ¼ outside radius to inside radius) of 3.0. A unified, dimen- sionless representation of the two-dimensional inside wall heat flux, and the dimensional inside wall heat flux ðq i ð/; zÞÞ and temperature ðT i ð/; zÞÞ data was found and used to collapse the data for all circumferential locations. Finally, 2-D boiling curves are presented and are among the first full set of 2-D boiling data presented for a single-side heated circular configuration. Ó 2003 Elsevier Ltd. All rights reserved. Keywords: Single-side heated circular tube; 3-D Water flow boiling 1. Introduction Since plasma-facing component (PFC) and electronic heat sink (EHS) design requirements, goals and objec- tives are evolving, the development of a high heat flux removal (HHFR) experimental conjugate multi-dimen- sional, flow boiling data base will provide the basis for CFD comparisons, flow boiling correlation modifica- tions, and adaptations which include single-side heating effects for detail PFC and EHS flow channel and sub- strate design studies. This will lead to cost-effective and robust designs. Many papers have been published re- porting either new or modified flow boiling correlations. Generally, there appears to be good confidence in pre- dicting water flow boiling for uniformly heated circular channels with or without twisted tapes. However, all PFCs and EHSs involve single-side heated flow channels and hence depend on at least two-dimensional, and in some cases three-dimensional, conjugate data and analysis for new or modified flow boiling or single-phase correlations with two- and possibly three-dimensional influences. Although HHFR designs and related innovations and improvements have been proposed for the PFCs in the International Thermonuclear Experimental Reactor (ITER) via the Engineering Design Activity by many investigators [1–13], additional divertor and PFC de- velopment and certification are ongoing for several new machines [9,14,15]. One principal machine concept being considered is the fusion ignition research experiment (FIRE). As noted by Ulrickson et al. [14], the primary focus of the FIRE program is an understanding of the plasma dominated by alpha heating. However, they also emphasized that a key issue of the FIRE design is HHFR from the outer divertor or PFC. Nygren [16] and Chappuis et al. [17] summarized prior experiences which may improve PFC functionality. Finally, R€ odig et al. [18] compared existing electron beam test facilities used in testing HHFR components. Fundamental HHFR research involving single-side heated flow channels is evolving. Boscary et al. [19] * Corresponding author. Tel.: +1-936-857-4811; fax: +1-936- 857-2325. E-mail address: ronald_boyd@pvamu.edu (R.D. Boyd). 0017-9310/03/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0017-9310(03)00102-9 International Journal of Heat and Mass Transfer 46 (2003) 4105–4117 www.elsevier.com/locate/ijhmt