Abstract
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.
Highlights
The pressure pulsation and dynamic fluid force of internal unsteady flow have significant influences on the performance and operation reliability of turbomachinery
The head and efficiency are calculated on basis of the stagnation pressure difference between the suction and discharge reference sections of pump, which is consistent in computational fluid dynamics (CFD) and experimental methods
The CFD results are validated by the experimental data
Summary
The pressure pulsation and dynamic fluid force of internal unsteady flow have significant influences on the performance and operation reliability of turbomachinery. They may result in excessive vibration and noise, and even lead to the fatigue failure of components. The reactor coolant pump (RCP) is a key piece of equipment in a nuclear power plant. It is used to force the coolant circulating in the primary loop of the pressurized water reactor (PWR), transferring heat from the nuclear fuel core to the steam generator [1]. The operation reliability of RCP is directly related to the safety of the nuclear power plant, which makes it crucial and significant to study the flow instabilities in RCP. Long et al [2,3]
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