Rotordynamic Analysis of Submerged Motor Pumps : Influence of Long Seal on the Stability of Fluid Machinery

Kanemori, Yuji; Iwatsubo, Takuzo

doi:10.1299/jsmec1993.37.193

Cited by 4 publications

(1 citation statement)

References 6 publications

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“…In addition, Kanemori and Iwatsubo (1992) stated that the rotor forward whirl acts as a stabilising force on the rotor. Kanemori and Iwatsubo (1994b) studied the mutual effects of cylindrical and conical whirl on the dynamic fluid forces and torques on a long annular seal experimentally. In addition to the rotordynamic coefficients the paper presents pressure measurements inside the annulus.…”

Section: Introductionmentioning

confidence: 99%

Dynamic force and torque characteristic of annular gaps -- Simulation results and evaluation of the relevance of the tilt and torque coefficients

Kuhr,

Nordmann,

Pelz

2021

Preprint

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We discuss the dynamic force and torque characteristic of annular gaps resulting from an axial flow component. First, the rotordynamic influence of annular gaps with an axial flow component is recapitulated. So far there is a severe lack of understanding the dynamic force and torque characteristic of annular gaps. Second, a new simulation method is presented, using a perturbed integro-differential approach in combination with power-law ansatz functions for the velocity profiles and a Hirs' model to calculate the dynamic force and torque characteristics. Third, an extensive parameter study is carried out. To evaluate whether or not the hydraulic tilt and torque coefficients need to be taken into account, an effective stiffness is defined and the influence of the annulus length, an eccentrically operated shaft, the centre of rotation, a modified Reynolds number, the flow number and the pre-swirl is investigated.

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Section: Introductionmentioning

confidence: 99%

Dynamic force and torque characteristic of annular gaps -- Simulation results and evaluation of the relevance of the tilt and torque coefficients

Kuhr,

Nordmann,

Pelz

2021

Preprint

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Dispersion Relation and Stability Analysis of Flow-Induced Wave of a Flexible Circular Ring Subjected to Swirling Fluid Flow

Watanabe

Kobayashi

2001

Journal of Pressure Vessel Technology

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This paper deals with a theoretical stability analysis of unstable wave generated in a flexible circular ring subjected to swirling fluid flow. The flexible circular ring is set in a rotating circular outer casing with a narrow gap filled with fluid and is subjected to the swirling fluid flow caused by the rotation of the outer casing. In the stability analysis, a wave equation is derived from the equation of motion of the flexible circular ring coupled with the swirling fluid flow. The equation of motion of the flexible circular ring is based on the Kirchhoff-Love’s thin-shell model, and the equations of motion of the swirling fluid flow are based on the Navier-Stokes equations. Moreover, the dispersion relation of the wave generated in the flexible circular ring is derived from the wave equation as a function of the rotational speed of the outer casing. The analytical results show that an unstable wave occurs as a type of traveling forward wave due to the swirling fluid flow when the rotational speed of the outer casing becomes high, and that the most unstable wave mode, phase speed (traveling-wave speed), and growth rate of the wave vary greatly with increasing rotational speed of the outer casing.

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Numerical and Experimental Research on the Fluid-Induced Forces of Clearance Flow in Canned Motor Reactor Coolant Pump

Long

et al. 2019

Journal of Engineering for Gas Turbines and Power

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Reactor coolant pump (RCP) is one of the most important equipment of the coolant loop in a pressurized water reactor system. Its safety relies on the characteristics of the rotordynamic system. For a canned motor RCP, the liquid coolant fills up the clearance between the metal shields of the rotor and stator inside the canned motor, forming a long clearance flow. The fluid-induced forces of the clearance flow in canned motor RCP and their effects on the rotordynamic characteristics of the pump are numerically and experimentally analyzed in this work. A transient computational fluid dynamics (CFD) method has been used to investigate the fluid-induced force of the clearance. A vertical experiment rig has also been established for the purpose of measuring the fluid-induced forces. Fluid-induced forces of clearance flow with various whirl frequencies and various boundary conditions are obtained through the CFD method and the experiment. Results show that clearance flow brings large mass coefficient into the rotordynamic system and the direct stiffness coefficient is negative under the normal operating condition. The rotordynamic stability of canned motor RCP does not deteriorate despite the existence of significant cross-coupled stiffness coefficient from the fluid-induced forces of the clearance flow.

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Rotordynamic Analysis of Submerged Motor Pumps : Influence of Long Seal on the Stability of Fluid Machinery

Cited by 4 publications

References 6 publications

Dynamic force and torque characteristic of annular gaps -- Simulation results and evaluation of the relevance of the tilt and torque coefficients

Dynamic force and torque characteristic of annular gaps -- Simulation results and evaluation of the relevance of the tilt and torque coefficients

Dispersion Relation and Stability Analysis of Flow-Induced Wave of a Flexible Circular Ring Subjected to Swirling Fluid Flow

Numerical and Experimental Research on the Fluid-Induced Forces of Clearance Flow in Canned Motor Reactor Coolant Pump

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