19-07-2012, 11:29 AM
Pump Testing
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Introduction and Background
This lab utilizes two water circulation pumps and examines the relationships between flow, power, head, and efficiency. In order to analyze this type of system, the TQ H32 pump testing skid is used; this apparatus has two identical pumps with valved piping configured in such a way that opening and closing certain valves allows each pump to be either isolated, or set in either series or in parallel with each other. The TQ H32 has a pressure gauge used to read the total output pressure of whichever configuration is currently being used. The hydraulic bench, used in previous experiments, serves as the water source as well as the collection tank, which is calibrated for volume measurement, and used calculate volumetric flow rate.
Procedure
To successfully perform this experiment, we connected the lower drain hose of the hydraulic bench to the pump system input and the output hose was set up to discharge into the bench tank in order to read volumetric flow rate. After making sure that the volumetric tank was empty, the water source reservoir was full, and both pumps were turned off, we were able to provide power to the system. Since the pumps were British made and run on 240Vdc, we ran our power input through an AC/DC converter and 120/240 V transformer.
Discussion Questions
1. What is the relative performance of the two pumps operating alone? Comment
The two pumps operating independently had very similar operation in terms of their Total Head vs. Flow plots in figure 4 with only two data points not directly aligning (possibly the result of human error in the flow measurement.) This is a good sign as the pumps are identical so they should operate with the same characteristics. The efficiencies in table 1 are also very similar for each pump independently at the same speeds also to be expected as the pumps are identical. The efficiencies are significantly lower than expected for each pump, but as mentioned earlier this is the result of improper measurement of the input power.