Losses in Piping Systems Experiment
Calculation Procedure and Results:
When performing the necessary calculations in this section, for water used in these experiments, assume an average density and (dynamic) viscosity of ρ = 995 kg/m3 and μ = 0.001 Pa-s, respectively. Also, where necessary, assume that the pipes used in these experiments can all be considered smooth (zero roughness).
Dark Blue Circuit and Gate Valve Calculation:
Using the experimental data of Table 2, calculate the velocity and Reynolds number for each run and enter the results in Table 4. Then using Darcy's equations given in page 1, calculate the experimental k or f*L/d as appropriate and enter the results in Table 4. Finally, using the Reynolds number for each run, determine the f*L/d (from Moody's diagram) and k (from tabulated results) and enter the results in the last 3 columns of Table 4.
Light Blue Circuit and Globe Valve Calculation:
Using the experimental data of Table 3, calculate the velocity and Reynolds number for each run and enter the results in Table 5. Then using Darcy's equations given in pages 1-2, calculate the experimental k or f*L/d as appropriate and enter the results in Table 5. Note that the experimental k value for sudden expansion and sudden contraction can be calculated by dividing their respective piezometric head by the velocity head (V2/2g) in the smaller pipe.
Finally, using the velocity upstream and downstream of the sudden expansion, first determine the head loss and then divide it by the upstream velocity head to find the theoretical k value for each run and enter the results in Table 5. For sudden contraction, using the area ratio, find the k value from published tables for each run and enter the results in the last column of Table 5.
Gate Valve and Globe Valve Performance Calculation:
As mentioned before, a Gate Valve is used to control the flow in the dark blue circuit while a Globe Valve is used for this purpose in the light blue circuit. In order to compare the resistance to the flow through each of these valves, the following calculations need to be performed:
Based on the data for the Dark Blue Circuit experiment given in Table 2, copy the Pressure Gauge and Velocity data in Table 6 and then find % Flow and Loss Coefficient (k) values and enter the data under Gate Valve in Table 6. % Flow is calculated by dividing the flow rate for each run by the maximum flow rate which is obtained when the valve is fully open (F/O Run). However, when the valve is fully open, the pressure drop across the valve is very small and it cannot be measured by the dial gauge. Therefore, for this experiment, assume that the flow for the lowest Gauge Pressure reading is the maximum flow (ie, Run No 1).
Discussions and Conclusions
Based on the experimental and theoretical friction loss results of Table 4 for the Dark Blue Circuit, compare these results and comment about their agreement or discrepancy. What are the causes of this discrepancy (if applicable)?
The friction loss results for the Light Blue Circuit are included in Table 5. First comment on the experimental results for all the fittings, and then discuss the agreement or discrepancy of the loss coefficient results for the sudden expansion and contraction reflected in the results of Table 5.
Using the data of Table 6, plot the Loss Coefficient (k) data for the two valves vs the % Flow on the same graph and comment on the performance of these valves compared to each other.
Using the data for the straight pipe section in both Dark and Light Blue Circuits from Tables 4 and 5, plot the experimental f*L/D values vs Re for the straight pipe on the same graph. How do these graphs compare with such graphs in the Moody's diagram?
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