水力自驱旋转式能量回收装置的转速推导

Rotating Speed Derivation of Hydro-Drive Rotary Energy Recovery Device

为建立海水淡化水力自驱旋转式能量回收装置(HRERD,Hydro-Drive Rotary Energy Recovery Device)转子转速与系统流量间的关联关系,对特定几何规格的能量回收装置的转速变化规律进行了理论推导和实验验证。运用动量定理建立了转子受流体水力冲击而产生的动力矩与转子转速的关系式;以微元法为基础,运用牛顿黏性定律建立了转子周面和端面因流体黏性阻力而产生的阻力矩与转子转速的关系式;利用转子稳定时所受动力矩与阻力矩间的平衡关系,推导得到装置转速与系统流量间的理论公式。对装置在系统流量分别为4.4、5.0、6.0和7.1 m^3·h^(-1)时的理论转速与实验转速比较分析表明,理论转速略高于实验转速,两者相对误差不超过12%,对误差形成的可能原因也进行了分析说明。

To establish the relationship between rotating speed of the rotor of hydro-drive rotary energy recovery device( HRERD) used in seawater desalination process and system flow,this article theoretically and experimentally derived the changing rules of rotating speed of a HRERD with specific geometric dimensions. The momentum theorem was utilized to establish the relationship between kinetic moment of the rotor caused by fluid's hydraulic impact and rotating speed. Newton's law of viscosity was utilized to establish the relationship between resisting moment of peripheral and end faces of the rotor caused by fluid's viscous drag and rotating speed based on infinitesimal method. Then the equilibrium relation between the kinetic and resisting moment of the rotor at its stable phase was utilized to derive a theoretical formula between rotating speed and system flow. Theoretical and experimental rotating speeds at 4. 4 m^3·h- 1,5. 0 m^3·h- 1,6. 0 m^3·h- 1,7. 1 m^3·h^(- 1) were then compared and analyzed. Results show that the theoretical rotating speeds are slightly larger than the experimental rotating speeds,and the relative errors between them are no more than 12%. This article also analyzed and explained the reasons for the relative errors.