オリフィス衝突噴流の流動・伝熱特性 : 絞り面積比の影響(熱工学,内燃機関,動力など)

概要

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The effects of nozzle contraction ratio on the flow and heat transfer characteristics of orifice impinging jet are investigated experimentally. The nozzle diameter is d_o=10.0 mm=const., and the contraction ratio CR=(d_o/d_i)^2, where di is pipe diameter, and the nozzle-plate distance are changed CR=1.00 to 0.11 and H/d_o=2.0 to 5.0, respectively. The Reynolds number based on d0 is Re=15 000=const. The flow characteristics are made clear by measurements of pressure and velocity distributions on the plate and flow visualization. The Nusselt number obtained by the measurements of temperature distribution on the plate for the orifice impinging jet of CR=0.11 and 0.69 were 19% and 9% higher than those of the pipe impinging (CR=1.00), respectively, because the centerline velocity of the orifice jet is larger than that of the pipe jet. Under the same operation power an orifice impinging jet has an enhanced heat transfer characteristics.
社団法人日本機械学会の論文
2008-03-25