プッシュプル完全局排方式に関する基礎研究 : 第1報,漏れ限界流量比とプッシュプル流れの特性(流体工学,流体機械)

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There are no investigations on the flow structure in the push-pull ventilation system except for the shutting or breaking limit flow ratio. For a push-pull local ventilation system, both a plane turbulent jet from a two-dimensional nozzle and suction flow into the hood opening, i.e. the push-pull jet flow, are utilized. However, although studies on turbulent jet structures have dealt with two-dimensional or axis symmetric jets into quiescent air, they have not investigated push-pull jet flow. In this report, we experimentally investigated the change of the mean velocity component profiles of the transient plane turbulent jet developing from a jet exit into the hood opening. The present profiles of dimensionless velocity u^^-/u^^-_m agree well with those for the conventional two-dimensional jet for dimensionless perpendicular coordinate y_1/b_<1/2>≦1.0, but are greater than those for y_1/b_<1/2>>1.0. The values of maximum mean velocity and half-width of the axial velocity profile along the centre-line of the jet are greater than the results for the conventional two-dimensional jet. For dimensionless coordinate in the flow direction x_1/L≧0.50, the observable effect of suction is remarkable on the axial and the lateral mean velocity components. The effects of suction rate are clarified on the distribution of the maximum values of the velocity profiles and the flow structure.
一般社団法人日本機械学会の論文
2009-05-25