In order to investigate the influence of characteristics parameters on detonation wave in a two - phase pulse detonation engine model . the peak detonation pressures and average velocities of two - phase pulsed detonation wave produced by pde model using gasoline as fuel and air as oxidizer under various ignition frequencies and various mixture ratios are measured systematically , and the relations influencing them are analyzed 为了探索气-液两相脉冲爆震发动机模型内特征参数对产生爆震波的影响规律,系统地测试了以汽油为燃料、以空气为氧化剂的气-液两相脉冲爆震发动机模型在不同点火频率及不同余气系数下爆震波的峰值压力以及平均爆震波速,并对其变化进行了分析。
Reynolds numbers ( based on average velocity at passage inlet and hydraulic diameter of the passage ) are changing from 20000 to 80000 and the extraction ratios ( suction ratios , sr ) are changing from 0 . 30 to 0 . 60 for each test model . so the influences of reynolds numbers , suction ratios and etc . on the discharge coefficients and pressure loss characterist ics are also presented . flow fields of typical passages are visualized with the flow visualization techniques and measured with hot - wire anemometer 对每一种通道结构,实验在不同通道进口雷诺数( re = 20000 、 40000 、 60000 、 80000 )和不同通道总出流比( sr = 0 . 30 、 0 . 45 、 0 . 60 )下进行,以研究这两个流动参数及其它相应变化的参数(气膜孔的雷诺数re _ h 、气膜孔与通道的动量比i等)对出流特性和流阻特性的影响规律。
And then simulations of gas - particle two phase plane wake and gas - particle two phase plane jet were carried out by using this model . after numerical simulations of the two flow fields were finished , series of analytical work was done . first , the distribution of time - averaged velocity , turbulence intensity was analyzed , and some of the simulation results were compared with those of the experiments ; the coherent structure of vortices in the near wall region of the plane wake flow were studied by describing the evolution of the eddy structures , including the forming , developing and shedding from the wall of the vortices in the near wall region ; the coherent structure of vortices in the whole field was also studied , such as the forming , developing , moving , pairing and merging of the eddies etc . 在对上述两种流动形态的二维大涡模拟研究中,首先全面地分析了气相时均流场的速度、湍流强度的分布规律以及气相速度的脉动规律等并就部分数值模拟结果与实验结果进行了对比研究;分析了平面尾迹流场中近壁处旋涡拟序结构,全面和逼真地反映了近壁处旋涡的生成、发展和脱落的规律;描述分析了平面尾迹流和平面射流的全场流动旋涡拟序结构,从整个流场的角度反映旋涡的生成、发展、运动以及旋涡之间相互配对、合并的作用规律等。
At last , three - dimensional mathematical model of gas - particle two phase turbulence was established , and it was adopted to study the gas - particle two phase rectangular jet as well . the distribution of the time - averaged velocity and turbulence intensity was studied , and some of the simulation results were compared with the experimental results ; the coherent structure of flow field was described in the three direction , the evolution and motion of the eddies was discussed too ; the dispersion of fine particles in the three dimensional space was also investigated 全面地分析了矩形射流气相时均流场的速度、湍流强度的空间分布规律,并就部分数值模拟结果与实验结果进行了对比研究;描述分析了气相流场湍流拟序结构,对流向、横向和展向三个方向旋涡的空间结构特点进行分析研究,并分析了流向涡随时间变化的发展、运动规律。
The tidal current in the radial sandbanks area apparently has directional to - and - fro movement , which can be observed not only from tidal ellipses , but also from water particle traces . the calculated distribution of tidal velocity in this area shows that the average velocity is around 0 . 6 to 1 . 0 m / s 平面潮流椭圆、水质点迹线、潮流流速特征研究表明,辐射状沙脊群海域潮流具有明显的定向往复流形式,平均潮流流速一般为0 . 6 1 . 0m s ,满足形成潮流沙脊的水动力条件。