Abstract
Based on the RNG k–ɛ turbulence model, the multi-coordinate system is used to simulate the three-dimensional unsteady constant value of the nuclear main pump model under different axial and circumferential positions of the guide vane and the annular casing. By analyzing the external characteristics, pressure field and velocity field of different schemes and comparing the pressure pulsation at the impeller outlet, the flow of guide vane and the annular casing is studied through the axial and circumferential position changes in the vane and the annular casing. The results show that the axial distance between the center line of the guide vane and the center line of the outlet extension will increase the uneven distribution of pressure in the impeller outlet and the annular casing and the circumferential position of the guide vane will increase as well. When the center lines of the two are coincident, the pressure distribution in the impeller outlet and the casing is relatively uniform. The change in the axial and circumferential positions of the guide vane of the nuclear main pump has little effect on the vector distribution of the impeller outlet flow, and the influence of liquid flow in the interior of casing is large. The impeller outlet pressure pulsation increases as the axial distance between the guide vane outlet center line and the annular casing outlet center line increases. When the two center lines coincide, the impeller outlet pressure pulsation peak is the lowest.
Highlights
The nuclear main pump is the only high-speed rotating equipment in the nuclear main pump circuit system
The results show that the pressure fluctuation intensity of the guide vanes channel is stronger than that of the impeller channel and weaken as the temperature increases
In the x = 0 scheme, the head and efficiency of the nuclear main pump model reach the maximum at the same time, which indicates that the performance of the nuclear main pump is optimal when the center line of the annular casing outlet of the model pump coincides with the center line of the guide vane outlet
Summary
The nuclear main pump is the only high-speed rotating equipment in the nuclear main pump circuit system. Effects of uneven guide blade on pressure fluctuation in different areas of model pump are of their own features. Li et al [12] found that the different axial vibration amplitudes and the width of the flow channel have an effect on the axial dynamic characteristics through the study of the clearance of the nuclear main pump. Xu et al [14] analyzed the pressure pulsation inside the nuclear main pump at different speeds and the uneven inflow under the corresponding speed and found that the low speed can reduce the vibration of the pump. The full flow field simulation of the nuclear main pump was carried out based on the RNG k–ɛ turbulence model in order to analyze the effect of the different axial placement positions of the guide vane.
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