二级洞塞泄流的消能特性分析

为了分析二级洞塞泄流的消能特性,揭示洞塞几何体形参数对洞塞泄流消能效果的影响规律,运用三维RNG k-ε紊流数学模型对洞塞泄流进行了数值模拟.建立了洞塞泄流的室内物理模型试验,利用模型试验结果对数学模型进行了验证,两者吻合较好.第1和第2级洞塞面积收缩比分别取为0.2,0.3,0.4和0.5,第1和第2级洞塞相对长度相等并分别取为0.5,1.5和3,形成144种工况.利用验证后的数学模型对上述144种工况进行计算和分析.结果表明：第1和第2级洞塞面积收缩比对消能率和消能比的影响较大,而相对长度对其影响很小.在其他几何体型参数一定的情况下,随着第2级洞塞面积收缩比的增大,第1级洞塞消能率和消能比相应增大,第2级洞塞消能率和消能比相应降低.在其他几何体型参数一定的情况下,随着第1级洞塞面积收缩比的增大,第1级洞塞消能率和消能比相应降低;第2级洞塞消能率变化不大,而消能比相应增加.当第1和第2级洞塞面积收缩比分别达到最小时,消能率达到最大.

Analysis on discharge energy dissipation in two-stage plugs

n order to analyze the discharge energy dissipation of a two-stage plug and reveal the inf-luence of its geometrical parameters on the dissipation,a three-dimensional RNG k-ε turbulence model was adopted to study discharge in the plug.A physical model of the plug was established to validate the computational results,good agreement has been achieved.The area contraction ratios of both plugs are 0.2,0.3,0.4 and 0.5,respectively,the relative lengths of two plugs are equal to 0.5,1.5 and 3,respectively,causing 144 experimental cases.Then the verified mathematical model of energy dissipation was used to estimate the discharge energy loss in the two-stage plugs at the 144 conditions.The results showed that the area contraction ratio influences the energy dissipation more significantly than the relative length.The energy dissipation rate and ratio of the first plug were increased,but those of the second-stage were decreased with increasing area contraction ratio of the second plug.The energy dissipation rate and ratio the first plug were decreased,the energy dissipation rate of second plug was varied little,but its energy dissipation ratio was increased with increasing area contraction ratio of the first plug.When the area contraction ratios of the two plugs were optimal,their energy dissipation rates were the largest.