Abstract
Pumping stations are important regulation facilities in a water distribution system. Intake structures can generally have a great influence on the operational state of the pumping station. To analyze the effects of the bell mouth height of the two-way intake on the performance characteristics and the pressure pulsations of a two-way pumping station, the laboratory-sized model pump units with three different intakes were experimentally investigated. To facilitate parameterized control, ellipse and straight lines were used to construct the profile of the bell mouth. The frequency domain and time-frequency domain of the pressure pulsations on the wall of intakes were analyzed by the Welch’s power spectral density estimate and the continuous wavelet transform (CWT) methods, respectively. The results showed that the bell mouth height (H) has significant influences on the uniformity of the impeller inflow and the operation stability of the pump unit. When H = 204 mm, the data fluctuated greatly throughout the test process and the performance curves are slightly lower than the other two schemes. As the bell mouth height gradually decreases, the average pressure difference of each measuring point began to decrease, more homogeneous velocity distribution of impeller inflow can be ensured. The amplitude of blade passing frequency is obvious in the spectrum. While when (H) is more than 164 mm, the main frequency of pressure pulsations at three points fluctuates with the rotation of the impeller. When H decreases to 142 mm, pressure pulsations will be independent of the operating conditions and positions which contributes to the long-term stable operation of the pump unit.
Highlights
Pumping stations play an important role in water resource allocation, agricultural irrigation and drainage, water environment improvement and urban flood fighting and drainage
When H decreases to 142 mm, pressure pulsations will be independent of the operating conditions and positions which contributes to the long-term stable operation of the pump unit
Long et al [10] numerically analyzed the inlet and outlet pressure pulsation characteristics of reactor coolant pumps with different inflows, the results show that the differences in both channel head and straight pipe inflows have significant effects on the unsteady pressure pulsation inside the pump
Summary
Pumping stations play an important role in water resource allocation, agricultural irrigation and drainage, water environment improvement and urban flood fighting and drainage. Through the control of the gate, water can be transferred between upstream and downstream This kind of pumping system has some disadvantages, such as low efficiency and easy to appear submerse vortex inflow passages, which may cause the unit vibration and does harm to the operating of pump unit [4,5]. Long et al [10] numerically analyzed the inlet and outlet pressure pulsation characteristics of reactor coolant pumps with different inflows, the results show that the differences in both channel head and straight pipe inflows have significant effects on the unsteady pressure pulsation inside the pump. The inlet flow field of the two-way pumping station was investigated, focused on the impeller inflow.
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