RT Journal Article ID 421767e6193531de A1 Jennerjohn, Mary A1 Lee, Junsik A1 Ren, Zhong A1 Ligrani, Phillip A1 McQuilling, Mark A1 Fox, Michael D. A1 Moon, Hee-Koo T1 JET ARRAY IMPINGEMENT COOLING LOCAL NUSSELT NUMBER VARIATIONS: EFFECTS OF HOLE ARRAY SPACING, JET-TO-TARGET PLATE DISTANCE, AND REYNOLDS NUMBER JF Heat Transfer Research JO HTR YR 2016 FD 2016-02-10 VO 47 IS 2 SP 119 OP 140 K1 impingement jets K1 impingement cooling K1 heat transfer augmentation K1 gas turbine AB Discussed in the article are the combined and separate effects of hole array spacing, jet-to-target plate distance, and Reynolds number on the local surface heat transfer rate for an impinging jet array. The array of impinging jets is directed to one flat surface of a channel which is bounded on three sides. Considered are the Reynolds numbers ranging from 8000 to 50,000, jet-to-target plate distances of 1.5D, 3.0D, 5.0D, and 8.0D, and the streamwise and spanwise hole spacing of 5D, 8D, and 12D, where D is the impingement hole diameter. Also included is a conduction analysis of the impingement cooling array target surface. In general, the local Nusselt numbers generally increase at each x/D location as either the Reynolds number increases, or as the X/D = Y/D hole spacing decreases. The highest Nusselt numbers are generally present at Z/D = 3.0 for Rej values of 8200, 20,000, and 30,000. When Rej = 52,000, the highest measured Nusselt number values are generally present for Z/D of either 1.5, 3.0, or 5.0, depending on the magnitudes of Rej, X/D, Y/D, and streamwise location x/D. The cumulative accumulations of crossflows, from sequential rows of jets, result in sequentially decreasing periodic Nusselt number variations with streamwise development. When examined at a particular value of Rej, the streamwise locations of the local maximum Nusselt numbers also shift to larger x/D locations as Z/D, the normalized jet-to-target distance, increases. The overall result is a complex dependence of local Nusselt numbers on the hole array spacing, jet-to-target plate distance, and impingement jet Reynolds number. PB Begell House LK https://www.dl.begellhouse.com/journals/46784ef93dddff27,49d564d677f1e773,421767e6193531de.html