摘要
通过对国内较推崇的几家沉速公式剖析认为(1)选择沙粒雷诺数R_(ed)和无因次粒径D_*作为颗粒沉降规律的控制参数,则所有与R_(ed)有关的参数均可表示成D_*的函数,流态亦由D_*判别,从而可建立避免试算的沉速公式.(2)绕流阻力一般式按阻力叠加原则取滞性阻力与形状阻力之和,其中滞性阻力宜取Stokes阻力与Oseen阻力的线性组合并转化为Newton阻力形式,形状阻力遵循Newton阻力定律,而两者的相对大小则通过以分离角表达的作用面积来反映.据此获得各绕流区统一的准理论性沉速公式(18),集各家公式之优点,经实测资料验证正确,可供实际应用.
After analysing several representative formulae for fall velocity, the author concludes that if the particle Reynolds-number (Red) and dimensionless grain-size(D*) are chosen as the controlling parameters of the settling movement, the fall velocity formula which avoids heavy and complicated trial-calculation may be established, because any parameter related to Red can be expressed as the function of D*. According to the superposition principle of resistance, the general expression (16) of the flow resistance has been derived in this paper, taken the weighed sum of the viscous friction and shape resistance by their relative action areas. With the formula(16), a quasi-theoretical generized formula(18) of the fall velocity for various passing-flow states has been obtained. The formula (18) assimilates the merits of several formulae and has been verified by experiment data, and can be applied to practical problem.
出处
《杭州大学学报（自然科学版）》
CSCD
1990年第2期246-255,共10页
Journal of Hangzhou University Natural Science Edition
关键词
颗粒
沉降
水
沉速
绕流阻力
fall velocity
passing-flow resistance
particle Reynolds-number
dimensionless grain-size
superposition principle of resistance
