离心泵转子动力学模型中流体力的简化

采用叶轮流体力的简化方式可以提高离心泵流体激励诱发振动的计算的准确程度。根据达朗伯原理对试验台架建立了包含离心泵基座的四圆盘三轴段转子动力学模型；将流体力分别简化为叶轮内20 %流体质量、40 %流体质量、CFD集中力与力矩，采用Newmark-隐式算法对转子动力学模型进行瞬态响应分析。结果表明，将叶轮上流体力简化为CFD；所得集中力与力矩时；可有效得出离心泵运转过程中流体激励所诱发的基座振动。而所获得的基座振动位移与加速度幅值均远大于将流体力简化为叶轮内20 %或40 %流体质量所获得的基座振动数值。另一方面，将流体力简化为叶轮内40 %流体质量所获得的基座振动大于简化为叶轮内20 %流体质量所获得的基座振动。

Simplification of Fluid Force in Rotordynamic Model ofCentrifugal Pumps

Researches on hydro force on impeller are significant for improving accuracy of computation on centrifugal pump vibration incited by fluid. A workbench of centrifugal pump rotor and antifriction bearing is firstly configed by installing vibration isolator on pump base, mounting corrugated pipe at pump import and export, and using electromagnetic coupling between motor shaft and pump shaft. Then a rotor dynamic model including four discs, three shaft sections and pump base is built for the workbench based on D'Alembert principle. And validation of the rotor dynamic model is also carried out by comparing base vibration from measurement with that from rotor-model transient response anlysis result, which is gained by Newmark- implicit algorithm and takes impeller concentrated fluid force as well as torque by CFD as incitation. At last, the fluid force on impeller is simplified to 20% fluid quality in impeller, 40% fluid quality in impeller, and concentrated force as well as torque by CFD respectively, compares among base vibrations by same Sine force on one disc in the model when the three simplifications are implemented for transient analysis respectively are also finished. The result shows that, the base vibration incited by fluid force during centrifugal pump operation can be effectively gained by simplifying fluid force on impeller to concentrated force and torque, and the amplitudes of base vibration acceleration and displacement by simplifying fluid force to concentrated force and torque are much larger than those by simplifying fluid force to 20% and 40% fluid weight in impeller respectively. Also, the acceleration and displacement amplitudes by 40% fluid weight in impeller are larger than those by 20% fluid weight in impeller. The rotor dynamic model built in this essay is effecive and reliable, and the workbench is feasible for validating and comparing accuracies of different simplifycations of fluid force.