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Yamano, Hidemasa; Tanaka, Masaaki; Iwamoto, Yukiharu*
Proceedings of ASME-JSME-KSME Joint Fluids Engineering Conference 2015 (AJK 2015-FED) (USB Flash Drive), p.231 - 240, 2015/07
This paper intends to validate the numerical simulation tool, the U-RANS approach with the Reynolds Stress Model. It is a commercial computational fluid dynamics code using single short-elbow in the 1/10 and 1/3 scale water experiments simulating JSFR hot-leg piping. The numerical results agreed with their experimental data for time-averaged velocity distributions, flow field visualization, and power spectral densities of pressure fluctuation. U-RANS numerical simulation tool validated single short elbow flow applicable. Also, unsteady flow fields in the show elbow flow with a cyclic secondary flow and the subsequent horse shoe vortex were shown. The numerical simulation results with or without the IHX plenum at the outlet from the effect of the outlet condition did not show significant difference in terms of the time-averaged velocity distribution, pressure fluctuation power spectral density. Hence the effect of the outlet condition is assumed to be negligibly small.
Iwamoto, Yukiharu*; Kusuzaki, Ryo*; Sogo, Motosuke*; Yasuda, Kazunori*; Yamano, Hidemasa; Tanaka, Masaaki
Proceedings of ASME-JSME-KSME Joint Fluids Engineering Conference 2015 (AJK 2015-FED) (USB Flash Drive), p.1767 - 1773, 2015/07
Wall pressure measurements and flow visualization were conducted for a 90 degree elbow of which the axis curvature radius became the same as its inner diameter (125 mm). A deflected inflow, having an almost constant velocity slope, was introduced. Ensemble averaged pressure distributions showed no normalized pressure difference in cases of Reynolds numbers of 320,000 and 500,000. Comparisons with uniform inlet flow case proved; low-pressure region at the intrados of the elbow was weakened whereas a high pressure region outside strengthened in the deflected inflow case. Pressure distribution downstream of the elbow increased at the inside until two diameters downstream from the elbow exit. Flow visualization showed the pressure increase from collision of a strengthened secondary flow of extrados convection. The unsteady pressure distribution showed a circumferential extent of a strongly fluctuating region in and downstream the elbow decreased, comparing with the uniform inlet flow case.