Unsteady Flow Structures and Pressure Pulsations in a Nuclear Reactor Coolant Pump With Spherical Casing

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Dan Ni ◽  
Minguan Yang ◽  
Ning Zhang ◽  
Bo Gao ◽  
Zhong Li
Keyword(s):  
Unsteady Flow ◽  
Nuclear Reactor ◽  
Internal Flow ◽  
Wake Flow ◽  
Flow Structures ◽  
Pressure Pulsations ◽  
Trailing Edge ◽  
Coolant Pump ◽  
Reactor Coolant ◽  
Vorticity Distribution

Severe vibrations induced by flow instabilities in the nuclear reactor coolant pump (RCP) are detrimental to the safe operation of the pump. Due to the particular spherical casing in the RCP, the internal flow structures are extremely ambiguity and complicated. The goal of the present work is to shed comprehensive light on the unsteady flow structures and its correlation with the pressure pulsations by using large eddy simulation (LES) method of the RCP. The vorticity distribution and the shedding vortex from the blade trailing edge are depicted in detail. Furthermore, the internal correlations between the flow unsteadiness and pressure pulsation are illustrated in some special regions of the RCP. Evidently, some main excitation components in the pressure spectra are excited by the shedding vortex. Besides, components at blade passing frequency (fBPF) are closely associated with rotor–stator interaction between the wake flow from the impeller outlet and unsteadiness vortexes shedding from the diffuser blade trailing edge. It is thought to be that the pressure pulsations of the RCP are closely associated with the corresponding vorticity distribution and the unsteady vortex shedding effect.

scholarly journals Flow Unsteadiness and Pressure Pulsations in a Nuclear Reactor Coolant Pump

2016 ◽  
Vol 62 (4) ◽  
pp. 231-242 ◽  
Author(s):  
Dan Ni ◽  
Minguan Yang ◽  
Bo Gao ◽  
Ning Zhang ◽  
Zhong Li
Keyword(s):  
Nuclear Reactor ◽  
Pressure Pulsations ◽  
Coolant Pump ◽  
Reactor Coolant ◽  
Flow Unsteadiness

Influence of Guide Vane Wrap Angle Key Design Parameters on Hydraulic Performance of Nuclear Reactor Coolant Pump

2014 ◽  
Vol 721 ◽  
pp. 73-77 ◽  
Author(s):  
Wei Nan Jin ◽  
Rong Xie ◽  
Mu Ting Hao ◽  
Xiao Fang Wang
Keyword(s):  
Flow Field ◽  
Nuclear Reactor ◽  
Guide Vane ◽  
Three Dimensional ◽  
Internal Flow ◽  
Hydraulic Performance ◽  
Design Parameters ◽  
Coolant Pump ◽  
Reactor Coolant ◽  
Wrap Angle

To study the effects of guide vane with different vane wrap angles and relative positions of outlet edge on hydraulic performance of nuclear reactor coolant pump, three-dimensional steady numerical simulations were performed by using CFD commercial software Numeca. The results show that the vane wrap angle changes the head and power characteristics by changing the relative velocity angle in vane outlet. The inner flow field changes while the wrap angle changes. With the wrap angle increases, the shock loss in volute is reducing, but the friction loss in vane passages is getting large. So there exists an optimum wrap angle and relative positions of outlet edge that corresponds to the highest efficiency of a pump. Numerical simulation is performed with the two key design parameters optimized through surrogate model, the internal flow field is improved and then the hydraulic efficiency is improved.

scholarly journals Effect of eccentricity on radial force and cavitation characteristics in the reactor coolant pump

2020 ◽  
pp. 312-312
Author(s):  
Yuanyuan Zhao ◽  
Xiuli Wang ◽  
Rongsheng Zhu
Keyword(s):  
Nuclear Power ◽  
Nuclear Reactor ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Radial Force ◽  
Asymmetric Structure ◽  
Two Phase ◽  
Coolant Pump ◽  
Cavitation Inception ◽  
Reactor Coolant

Nuclear reactor coolant pump as one of the most critical equipment is the only one rotating equipment in first loop system of nuclear power plant. Due to the asymmetric structure of the pump body, especially the existence of outlet segment lead to a certain of radial force, the magnitude of radial force directly affects the work stability of the reactor coolant pump. The nuclear reactor coolant pump could stability work under those transient complex conditions is an important index of its performance. To study the cavitation characteristics and radial force of reactor coolant pump on transient cavitation, a prototype pump and those exhibiting different gravity center offsets are analyzed numerically with CFD software ANSYS CFX by employing RNG k-? model and two-fluid two-phase flow model. Through the experiment-combined simulation, the variations of cavitation characteristics and radial force of the reactor coolant pump under different eccentricities are characterized. As revealed from the results, the flow characteristics of the internal flow field of the nuclear main pump change after the axis is offset by different distance. The influence of eccentricity on the cavitation of the nuclear main pump is mainly manifested at the impeller inlet from cavitation inception to severe cavitation. When the eccentricity is 5mm, the cavitation performance is improved. The effect of eccentricity on the radial force of impeller is reflected in the variation of force direction. Compared with other plans, the radial force is superior in transient cavitation under the eccentricity of 5mm.

scholarly journals Effect of Suction and Discharge Conditions on the Unsteady Flow Phenomena of Axial-Flow Reactor Coolant Pump

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1592
Author(s):  
Xin Chen ◽  
Shiyang Li ◽  
Dazhuan Wu ◽  
Shuai Yang ◽  
Peng Wu
Keyword(s):  
Unsteady Flow ◽  
Pressure Pulsation ◽  
Flow Reactor ◽  
Axial Flow ◽  
Hydraulic Performance ◽  
Uniform Flow ◽  
Coolant Pump ◽  
Reactor Coolant ◽  
Flow Phenomena ◽  
Rotating Impeller

In order to study the effects of the suction and discharge conditions on the hydraulic performance and unsteady flow phenomena of an axial-flow reactor coolant pump (RCP), three RCP models with different suction and discharge configurations are analyzed by computational fluid dynamics (CFD) method. The CFD results are validated by experimental data. The hydraulic performance of the three RCP models shows little difference. However, the unsteady flow phenomena of RCP are significantly affected by the variation of suction and discharge conditions. Compared with that of Model E-S (baseline, elbow-single nozzle), the pressure pulsation in rotating frame of Model S-S (straight pipe-single nozzle) and Model E-D (elbow-double nozzles) is weakened in different degrees and forms, due to the more uniform flow fields upstream and downstream of the impeller, respectively. It indicates that the generalized rotor-stator interaction (RSI) actually exists between the rotating impeller and all stationary components causing the circumferentially non-uniform flow. Furthermore, improving the circumferential uniformity of the flow upstream and downstream of impeller (suction and discharge flow) also contributes to reducing the radial dynamic fluid force acting on the impeller. Compared with those of Model E-S, the dynamic FX and FY of Model S-S are severely weakened, and those of Model E-D also gain a minor amplitude decrease at fBPF. In contrast, the general pressure pulsation in fixed frame is mainly related to the rotating impeller and barely affected by the suction and discharge conditions.

Study on the transient evolution law of internal flow field and dynamic stress of reactor coolant pump under rotor seizure accident

2019 ◽  
Vol 133 ◽  
pp. 35-45
Author(s):  
Xiuli Wang ◽  
Yonggang Lu ◽  
Rongsheng Zhu ◽  
Qiang Fu ◽  
Yiming Chen ◽  
...  
Keyword(s):  
Flow Field ◽  
Dynamic Stress ◽  
Internal Flow ◽  
Coolant Pump ◽  
Evolution Law ◽  
Reactor Coolant

Numerical Simulation of Interior Flow Field of Reactor Coolant Pump under Station Blackout Accident

2012 ◽  
Vol 455-456 ◽  
pp. 1002-1008 ◽  
Author(s):  
Yi Ming Xu ◽  
Shi Ming Xu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Internal Flow ◽  
Simulation Method ◽  
Governing Equations ◽  
Coolant Pump ◽  
Reactor Coolant ◽  
Internal Characteristic ◽  
Station Blackout ◽  
Interior Flow

Numerical simulation is used for researching the transient characteristic and internal characteristic of the reactor coolant pump under station blackout accident. The simulation method has been presented by analyzing difference scheme for governing equations. The analytical model of reactor coolant pump flow field has been established by analyzing adequately the influence of varying rotation speed to the pump external characteristic. Finally, the pump internal flow characteristic is exposed.

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