Experimental Investigation on Unsteady Pressure Pulsation in a Centrifugal Pump With Special Slope Volute

Zhang, Ning; Yang, Minguan; Gao, Bo; Li, Zhong; Ni, Dan

doi:10.1115/1.4029574

Cited by 82 publications

(32 citation statements)

References 20 publications

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“…To guarantee the computational accuracy, the fine grids were necessarily required by the LES model. Thus, grid cells near the solid wall were encrypted, especially on the surface of the blades, where significant pressure gradients and flow separation may easily occur [12] and [13]. Meanwhile, a detailed grid sensitivity analysis with four different mesh numbers has been carried out, as summarized in Table 2.…”

Section: Mesh Generationmentioning

confidence: 99%

“…The unsteady flow structure of a mixed-flow nuclear reactor coolant pump, especially in certain specific regions, is very important to the safety analysis of a nuclear reactor, as it could generate serious flow-induced vibration, threatening the pump integrity [8]. Therefore, a comprehensive analysis and prediction of pressure pulsation caused by intense rotor-stator interaction are essential for the design of the mixed-flow nuclear reactor coolant pump [12] and [13]. At present, in order to improve the efficiency and stable operation of the nuclear reactor coolant pump, the complicated internal unsteady flow structures should be thoroughly illustrated.…”

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confidence: 99%

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Flow Unsteadiness and Pressure Pulsations in a Nuclear Reactor Coolant Pump

Ni¹,

Yang²,

Gao³

et al. 2016

SV-JME

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A nuclear reactor coolant pump (RCP) [1], the device in the reactor core and the steam generator that transfers the heat energy [2], is the "heart" of a nuclear reactor driving the circulation flow of the coolant in the main loop [3]. The nuclear reactor coolant pump is the only rotating part of the nuclear island, so it belongs in a nuclear safety grade one facility. Moreover, it is also the main energy-consuming equipment in the nuclear power plants, which must be guaranteed to operate continuously over a long term and without trouble. An investigation on the internal flow in the mixed-flow nuclear reactor coolant pump is one of the key problems for the development of reactor coolant pumps in large pressurized water reactors. Some investigations have been conducted to study the design of the mixed-flow pump [4] and [5] and flows instabilities [6] and [7]. However, most of them only focus on the unsteady pressure pulsation in impeller [8] and [9] or the performance of the nuclear reactor coolant pump [10] and [11]. The unsteady flow structure of a mixed-flow nuclear reactor coolant pump, especially in certain specific regions, is very important to the safety analysis of a nuclear reactor, as it could generate serious flow-induced vibration, threatening the pump integrity [8]. Therefore, a comprehensive analysis and prediction of pressure pulsation caused by intense rotor-stator interaction are essential for the design of the mixed-flow nuclear reactor coolant pump [12] and [13]. At present, in order to improve the efficiency and stable operation of the nuclear reactor coolant pump, the complicated internal unsteady flow structures should be thoroughly illustrated.The nuclear reactor coolant pump has a special structure equipped with a spherical casing, which determines a typical and complex flow pattern within the pump. Knierim et al.[14] designed a new type of reactor coolant pump for a 1400 MW nuclear power plant. The impeller and diffuser were gradually optimized based on the computational fluid dynamics (CFD). The volute casing is a spherical shape with a discharge nozzle facing the impeller, and the flow structures in the region around the discharge nozzle are uniform. The region of the discharge nozzle itself is characterized by the fact that the flow below the outlet port is divided into two parts. One portion flows out of the casing discharge nozzle, whereas the other portion circulates around the casing once more prior to exiting. Kato et al.[15] and [16] described internal flows of a high-specific-speed mixed-flow pump at low flow rates using large-eddy simulation (LES), and it showed that the head-flow curve exhibited weak • Flow separations and backflows easily occur at the diffuser channels near the discharge nozzle region.• At the left region of the casing, the discharge nozzle is affected significantly by an intense rotor-stator interaction effect.• In the right and middle of the casing nozzle, unsteady flow structures are more complicated.• An unsteady vortex-shedding effect would motivate evid...

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Section: Mesh Generationmentioning

confidence: 99%

mentioning

confidence: 99%

Flow Unsteadiness and Pressure Pulsations in a Nuclear Reactor Coolant Pump

Ni¹,

Yang²,

Gao³

et al. 2016

SV-JME

Self Cite

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show abstract

“…In terms of pressure pulsation and radial force, Gao et al [15] studied the static performance and pressure fluctuation of a large centrifugal pump and determined the main frequency of mine monitoring points; their findings agreed well with experimental data. Zhang et al [16] investigated a conventional spiral volute pump and demonstrated how slope volute contributes to the significant decline of pressure pulsation. Pei et al [17][18][19] investigated the flow unsteadiness behavior of a centrifugal pump and reported the significant effect of flow rate on time-averaged unsteadiness and distribution of turbulence intensity.…”

Section: Prefacementioning

confidence: 99%

Effects of Impeller Diameter on High‐Speed Rescue Pump

Bai

Kong

Xia

et al. 2017

Mathematical Problems in Engineering

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Impeller diameter is a crucial design parameter of high-speed rescue pumps because it affects the performance and inner flow characteristics of these pumps. In this study, a pump with an impeller diameter of 248 mm was modeled and its performance was tested. Numerical simulations were conducted under steady and unsteady states, in which the sizes of the impeller diameters were designated as 248 mm (original), 235.6 mm (5% trimmed), 223.2 mm (10% trimmed), and 210.8 mm (15% trimmed). ANSYS software was used to test the shear stress transport (SST -) of the four models, and results agreed well with experimental data. Diameter size affected impeller characteristics in both steady and unsteady states. Subsequently, the differences in performance, hydraulic loss, pressure pulsation, and radial force of the impellers were evaluated. In the performance test, the head and efficiency of the pump decreased as impeller diameter was reduced. The result trends are in accordance with the trim law within the acceptable error range. In terms of hydraulic loss, the impeller and diffuser vane components presented opposite trends with flow rate increase. Finally, in terms of pressure pulsation and radial force, the amplitude diminished while periodicity improved as impeller diameter decreased. PrefaceThe number of mining flooding accidents has increased in China and in other countries, and rescue operation groups have since demanded for lower-volume, higher-powered, and higher-speed pumps compared with conventional types. The current rescue pumps used for mining flooding are the multistage types, which have sufficient power and head to alleviate flooding from the bottom to the ground, but are complex and too large to use in narrow mining wells [1][2][3][4]. Consequently, the research groups at Jiangsu University that are in charge of rescue pump development have designed a series of smallvolume, high-powered, and high-speed rescue pumps that can be easily used during mining flooding incidents.In recent years, computational fluid dynamics (CFD) analysis has been applied to the hydrodynamic design of several pump types due to the following reasons. First, the outcomes of hydraulic design and performance are difficult to predict because of complex geometric parameters. Second, constructing and testing physical prototypes are expensive and time-consuming endeavors, which reduce the profit margins of pump manufacturers. Consequently, several studies have been conducted on CFD to serve as guides for pump design and optimization [5][6][7][8][9][10][11][12][13][14]. In terms of pressure pulsation and radial force, Gao et al. [15] studied the static performance and pressure fluctuation of a large centrifugal pump and determined the main frequency of mine monitoring points; their findings agreed well with experimental data. Zhang et al.[16] investigated a conventional spiral volute pump and demonstrated how slope volute contributes to the significant decline of pressure pulsation. Pei et al. [17][18][19] investigated the flow unsteadiness ...

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“…And grid cells near surface were encrypted as shown in Figure 2, especially on the surface where the pressure gradients are large and flow separation easily occurs [17]. The value of maximum layers of boundary layer was set to 20; the thickness of the first layer of boundary layer was less than 0.01 mm in order to ensure the value + ≤ 1 near the wall.…”

Section: Parametersmentioning

confidence: 99%

Analysis of Pressure Pulsation Induced by Rotor-Stator Interaction in Nuclear Reactor Coolant Pump

Zhang

Wang

Ruan

et al. 2017

Shock and Vibration

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The internal flow of reactor coolant pump (RCP) is much more complex than the flow of a general mixed-flow pump due to high temperature, high pressure, and large flow rate. The pressure pulsation that is induced by rotor-stator interaction (RSI) has significant effects on the performance of pump; therefore, it is necessary to figure out the distribution and propagation characteristics of pressure pulsation in the pump. The study uses CFD method to calculate the behavior of the flow. Results show that the amplitudes of pressure pulsation get the maximum between the rotor and stator, and the dissipation rate of pressure pulsation in impellers passage is larger than that in guide vanes passage. The behavior is associated with the frequency of pressure wave in different regions. The flow rate distribution is influenced by the operating conditions. The study finds that, at nominal flow, the flow rate distribution in guide vanes is relatively uniform and the pressure pulsation amplitude is the smallest. Besides, the vortex shedding or backflow from the impeller blade exit has the same frequency as pressure pulsation but there are phase differences, and it has been confirmed that the absolute value of phase differences reflects the vorticity intensity.

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Experimental Investigation on Unsteady Pressure Pulsation in a Centrifugal Pump With Special Slope Volute

Cited by 82 publications

References 20 publications

Flow Unsteadiness and Pressure Pulsations in a Nuclear Reactor Coolant Pump

Flow Unsteadiness and Pressure Pulsations in a Nuclear Reactor Coolant Pump

Effects of Impeller Diameter on High‐Speed Rescue Pump

Analysis of Pressure Pulsation Induced by Rotor-Stator Interaction in Nuclear Reactor Coolant Pump

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