In which conditions we should use mean diameter foe calculation of blade speed in pump and turbine?
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The pump investigated in this study was GPQ200-300, which is a typical high-speed rescue pump. The design parameters are provided in Table 1, and the model is presented in Figure 1. The nomenclature of all the symbols, including scalars and vectors, is listed in Nomenclature.
Table 1: Main parameters of original high speed rescue pump.
Figure 1: Model of rescue pump.
3. Test Rig
The test rig was acquired from the Hefei Hengda Group (China) (Figure 2). The pump was driven by a transducer that transferred current from the power network at a frequency range of 50–100 Hz. Flow rate was adjusted through a valve located near the outlet duct of the pump. Flow magnitude was calculated using an LWGY-200A turbine flow meter with a measurement uncertainty of 0.5%. The inlet and outlet sections of the pump were affixed to two WT200 intelligent pressure tensors that collected mean static pressure at 0.1% uncertainty. Finally, the electric signal and input power were measured from the transducer, which was connected to a computer equipped with data acquisition software.
Figure 2: Test rig.
In addition, the test was carried out according to Chinese National Precision Grade Number 2 regulations which can be seen in Table 2.
Table 2: Test precision standard of grade 2 in China.
The performance curves of the test rig are shown in Figure 3. The pump performed at the optimum and close to the design point based on the experimental results. The pump head decreased when flow exceeded the design point. This condition might have been caused by the extraordinarily high speed and high power of the pump. Simultaneously, impact loss manifested as high flow rates due to the limited components of overflow. When the deviation from the design point is significant, the performance impact is more drastic. In the experiment, “efficiency” was represented by crew efficiency and measured in terms of power transmitted by the converter output. Overall, pump performance matched the requirements of the design.
Figure 3: Experimental results.
Table 1: Main parameters of original high speed rescue pump.
Figure 1: Model of rescue pump.
3. Test Rig
The test rig was acquired from the Hefei Hengda Group (China) (Figure 2). The pump was driven by a transducer that transferred current from the power network at a frequency range of 50–100 Hz. Flow rate was adjusted through a valve located near the outlet duct of the pump. Flow magnitude was calculated using an LWGY-200A turbine flow meter with a measurement uncertainty of 0.5%. The inlet and outlet sections of the pump were affixed to two WT200 intelligent pressure tensors that collected mean static pressure at 0.1% uncertainty. Finally, the electric signal and input power were measured from the transducer, which was connected to a computer equipped with data acquisition software.
Figure 2: Test rig.
In addition, the test was carried out according to Chinese National Precision Grade Number 2 regulations which can be seen in Table 2.
Table 2: Test precision standard of grade 2 in China.
The performance curves of the test rig are shown in Figure 3. The pump performed at the optimum and close to the design point based on the experimental results. The pump head decreased when flow exceeded the design point. This condition might have been caused by the extraordinarily high speed and high power of the pump. Simultaneously, impact loss manifested as high flow rates due to the limited components of overflow. When the deviation from the design point is significant, the performance impact is more drastic. In the experiment, “efficiency” was represented by crew efficiency and measured in terms of power transmitted by the converter output. Overall, pump performance matched the requirements of the design.
Figure 3: Experimental results.
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