Lab 3 Pump Characteristics

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Figure 1: Pump performance curve for big centrifugal pump

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Figure 2: Pump performance curve for small centrifugal pump (high speed)

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Figure 3: Pump performance curve for small centrifugal pump (low speed)

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Figure 4: Pump performance curve for gear pump (high speed)

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Figure 5: Pump performance curve for gear pump (low speed)

Discussion

For each pump speed, the pump performance curves were plotted (Figure 1- 5), from the Figure 2 and 3 which is the pump performance curves for small centrifugal pump, the curves were unexpected. Since this sets of data (Table 2) were the first data collections, students in our group were not familiar with the derive, and the gage pressure stayed low at the beginning of the lab, so the some bad data were collected, and the curves were invalid. According to Table 1 and 3, respectively, for the big centrifugal pump, the pump seems to be most efficient for flowrate around 0.0012m^3/s, the gear pump seems to be most efficient for flowrates 0.0024 and 0.0018 m^3/s. According to Figure 1, the centrifugal pump, especially the big one, produces large head rise with relatively small flowrates. The gear pump (positive displacement) produces relatively high flow with the lower head rise than big centrifugal pump. It can be inferred that for projects that require high flow with low head, the gear pump will be most suitable. For projects that require high head with low flow, the centrifugal pumps will be most appropriate. For the free delivery estimate table (Figure 5), due to the lab errors, the free delivery estimates for small centrifugal pump cannot be estimated. According to the big centrifugal performance curve (Figure 1) the operating point for question 4 can be estimated to be flowrate around 0.00135m^3/s.

Conclusion

The experiment is done and succeeds but the second part of test (small centrifugal test). Big centrifugal pump works most efficiently under flowrate around 0.0012m^3/s, and positive displacement pump works most efficiently under flowrate around 0.0021m^3/s on average. The positive displacement pumps are most suitable for projects that require high flow with low head rise, and the centrifugal pumps are most suitable for projects that require high head rise with low flow.

Appendix:

Table 5: Dimensions of big centrifugal pump

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Table 6: Dimensions of small centrifugal pump

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Table 7: Dimensions of positive displacement

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Introduction

10

Methods

10

Results

10

Discussion

10

Conclusion

10

Style, clarity, format, etc.

25

Questions

25

Total

100