低质量流速垂直和倾斜并联内螺纹管两相流不稳定性研究

在200~450 kg/(m2.s)的低质量流速下,采用31.8 mm×6 mm的6头内螺纹管,在高压试验台上进行了垂直和倾斜并联内螺纹管两相流不稳定性对比试验研究.研究表明:对压力降脉动和密度波脉动,随着进口压力和质量流速的增加,发生脉动的界限热负荷增加,垂直并联管的界限热负荷总是大于倾斜并联管,说明垂直并联内螺纹管的稳定性更好;过冷度对脉动发生的界限热负荷和脉动周期的影响出现不同的趋势.通过对试验数据进行回归处理,给出了两种条件下发生不稳定性脉动的起始点无因次准则方程.

Two-Phase Flow Instability in Vertical and Inclined Parallel Rifled Tubes at Low Mass Velocity

An experiment was conducted to investigate the two-phase flow instability in the vertical parallel rifled tubes and inclined parallel rifled tubes using six-head rifled tubes with a diameter of 31.8 mm in the mass flow rate range of 200-450kg/(m~2·s)in a high pressure test loop.The experimental results show that the boundary heat flux of the pressure-drop type oscillation or the density-wave type oscillation increased with the increase of the inlet pressure and the mass flow rate,and the boundary heat flux for the vertical parallel rifled tubes was greater than that for inclined parallel rifled tubes,indicating that the flow in vertical parallel rifled tubes would be more stable.The effects of inlet subcooling degree on the boundary heat flux and the oscillation period exhibited two different trends in the test.In addition,non-dimensional correlations of thresholds of heat flux both in the vertical parallel rifled tube and the inclined parallel rifled tube were obtained by the regression calculation of the test data.