涡轮流量计的二元流动理论模型

本文应用二元边界层理论的动量积分关系式导出了作用于涡轮流量计叶片上粘性摩擦阻力矩T_(fb)的理论模型。并给出应用二元叶栅理论所获得的涡轮流量计驱动力矩T_d的表达式。计算表明作用于叶片上的粘性摩擦阻力矩的大小具有与驱动力矩相同的数量级。文章还应用流体力学基本理论给出了涡轮流量计的轮壳阻力矩T_(fh)、阻力矩T_(ft)、轴承阻力矩T_(fj)和轮壳端面阻力矩T_(fe)的计算公式。计算表明,叶顶其中轮壳阻力矩比其他阻力矩(除粘性摩擦阻力矩之外)均大一个数量级以上。文章又通过涡轮流量计的平衡方程式计算出涡轮流量计的仪表常数。结果表明,计算值与实测值甚为吻合。

Two-dimensional Flow Model of Turbine Flowmeter

In this paper the viscous frictional torgues T_(fb) exerted on the blades of a turbine flowmeter are studied and described in details in terms of two-dimensional boundary layer theory. The driving torque T_d of turbine flowmeter is also presented by means of the two-dimensional cascade theory. The results of calculation indicate that the blade frictional torques have a magnitude equal to that of the driving torques. By using fluid flow theory the other retarding torques,i.e, rotor hub viscous frictional torques T_(fh), blade tip clearance drag torques T_(ft), bearing retarding torques T_(fi) and hub ends retarding terques T_(fe) are presented. It is shown that the rotor hub viscous frictional torques have a larger magnitude than the other retarding torques. The factor of a turbine flowmeter is obtained by virtue of the equilibrium equation. The calculation results of the meter factor are fully in agreement with the experimental data.