Simulation of a hydraulically controllable reactor coolant pump seal

Salant, Richard F.; Payne, John W.; Johnson, William R.; Boles, Gary

doi:10.1016/j.triboint.2018.02.024

Cited by 12 publications

(7 citation statements)

References 3 publications

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“…Pang [5] considered the different pressure loads in the cavity resulting from the different spindle eccentricities as pulsating excitations on the dynamic ring and studied the influence of the seal excitation force on system stability. Salant [6] set the axial resultant force on the moving ring as the impact excitation due to the influence of the end groove and end-face deformation on the body film pressure and calculated the distance between the moving and stationary rings and the leakage of the system. Varney [7] studied the influence of the deviation in installation coaxiality on the system.…”

Section: Introductionmentioning

confidence: 99%

Stability Analysis of Hydrodynamic Mechanical Seals in Multifrequency Excitation

Sun

Liu

et al. 2023

Coatings

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The dynamic characteristics of the complex relationship among the sealing system, excitation, and response have a considerable impact on the operational reliability of hydrodynamic mechanical seals, which is a critical issue in the field of sealing theory and technology. Scholars at home and abroad have established dynamic models and calculated the displacement responses of dynamic and static rings in the time domain based on the force on these rings so that the response results can be used for system stability analysis. Neither are the excitation characteristics of cavitation load extracted, nor are the distance response and system leakage rate of the dynamic and static rings analyzed under coupled cavitation and random excitation. In this study, under different operating conditions of the hydrodynamic mechanical seal system, the liquid film evaporation load and seismic load are applied to study the frequency domain response of the distance between the dynamic and static rings and the system leakage rate. The following conclusions have been obtained: Assuming that the chamber pressure is 0.5 MPa and the spring specific pressure is 0.055 MPa, during stable operation, the distance between the moving and stationary rings at 1500 rpm~3000 rpm speeds is 1.12 μm~3.05 μm. For a specific spring pressure of 0.055 MPa, medium pressures of 0.2 MPa~1.0 MPa, and spindle speeds of 1500 rpm~3000 rpm, the excitation force is 30 N, and the frequency is 30 Hz, And the seismic load is assumed to be sinusoidal, the excitation force is 6 N, the fundamental frequency is 120 Hz, and the system leak rate is in 0.1 mL/min~1.3 mL/min. Under multi-frequency excitation coupling, the distance between the dynamic and static rings will decrease as the pressure of the medium in the sealing cavity increases, and this will increase with the increase in the rotating speed. The leakage rate of the system will increase with the increase in the rotating speed and the pressure of the medium, and the test value is largely consistent with the theoretical value.

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Section: Introductionmentioning

confidence: 99%

Stability Analysis of Hydrodynamic Mechanical Seals in Multifrequency Excitation

Sun

Liu

et al. 2023

Coatings

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“…The wavy-tilt-dam (WTD) seal is one of the hydrodynamic mechanical face seals used in nuclear reactor coolant pumps (RCPs) [1]. Generally, one RCP is equipped with three WTD seals, and each seal has the ability to undertake an entire system load of no less than 15.3 MPa [2,3]. Therefore, it is desirable that the WTD seals possess excellent mechanical properties, heat transfer characteristics, thermal environment resistance, chemical stability, sliding compatibility, and high durability [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Positioning Accuracy Determination of the Servo Axes for Grinding Wavy-Tilt-Dam Seals Using a Four-Axis Grinder

Gao

2021

Micromachines

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The wavy-tilt-dam (WTD) seal is considered to be one of the ideal sealing patterns used in nuclear reactor coolant pumps (RCPs). Grinding such seals with a four-axis grinder had been proposed and six grinding implementation strategies were described in our previous studies. However, another important issue is to determine the positioning accuracy of each servo axis so that the high-precision moving components can be selected properly. In the present paper, the positioning accuracy analysis is carried out to seek a balance between the manufacturing cost and the accuracy requirements. First, a geometric model is established for investigating the error sensitivity of each axis and setting reasonable accuracy allocation of the four axes. Subsequently, the combined influence of all four axes is assessed based on multi-body system (MBS) theory and homogeneous transformation matrix (HTM). According to the results calculated, positioning errors of the X-axis, Z-axis, B-axis, and C-axis within ±10 μm, ±0.1 μm, ±1 arcsec and ±60 arcsec are acceptable, respectively. Meanwhile, the form error calculated of the ground wavy face is no more than 109.74 nm. It is indicated that the accuracy level of the moving components is achievable by modern manufacturing techniques. The present paper is expected to serve as a theoretical basis for the design and development of the four-axis grinder.

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“…The shaft seal is an isolation device to prevent the leakage of reactor coolant pumps (RCP) (Salant et al, 2018), which is directly related to the safe operation of the nuclear power plant (Nilsson et al, 2009;Baraldi et al, 2011;Feng et al, 2016;Kok and Benli, 2017;Luqman et al, 2019). As one of the key components of shaft seals, the mechanical seal (Harp and Salant, 1998;Clark et al, 2002;Simon, 2018) plays a vital role in the safety and reliability of the entire structure, where different shapes of its end face lead to the different hydraulic effects (hydrodynamic and hydrostatic effects).…”

Section: Introductionmentioning

confidence: 99%

Characteristics of the Waviness End-Face Mechanical Seal in Reactor Coolant Pump Considering the Viscosity-Temperature Effect

Ma¹,

Wang²,

Zhou

et al. 2021

Front. Energy Res.

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Mechanical seals prevents flow leakages in reactor coolant pumps thus playing an important role in their operational safety. However, their operational performance depends on different parameters, the seal geometrical design and the sealing medium characteristics among others. This study investigates the main performances of the waviness end-face mechanical seal, considering the effect of fluid flow and thermal characteristics. The involved coupled thermal-hydraulic process is simulated using the OpenFOAM, based on the coupled Navier-Stokes and energy balance equations. Study results showed that the viscosity-temperature effect may increase the flow leakage, and decrease both the opening force and the liquid film stiffness. The later may be decreased to negative values under specific conditions. It’s therefore generally found that visco-thermal characteristics of the sealing medium may negatively affect mechanical seal’s operational stability. On the other hand, from the perspective of liquid film temperature rise, the visco-thermal effect may lead to the regulation of the temperature rise in the liquid film, which improves the mechanical seal’s operational safety in some aspects. Through a comprehensive analysis, the optimal structural parameters of the waviness mechanical seal investigated in this study are found to be hi = 2.5μm, β = 900μrad (Rd-Ri)/(Ro-Ri) = 0.2, α = 0.8, and k = 9.

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Simulation of a hydraulically controllable reactor coolant pump seal

Cited by 12 publications

References 3 publications

Stability Analysis of Hydrodynamic Mechanical Seals in Multifrequency Excitation

Stability Analysis of Hydrodynamic Mechanical Seals in Multifrequency Excitation

Positioning Accuracy Determination of the Servo Axes for Grinding Wavy-Tilt-Dam Seals Using a Four-Axis Grinder

Characteristics of the Waviness End-Face Mechanical Seal in Reactor Coolant Pump Considering the Viscosity-Temperature Effect

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