sujan lab 4

Table of Contents Introduction & Objective …………………………………………………… 1 Apparatus & Procedure …………………………………………………… 2 Results …………………………………………………………………… 3 Discussion …………………………………………………………………… 9 Conclusion …………………………………………………………………… 9 References …………………………………………………………………… 11 Appendix …………………………………………………………………… 12 Introduction & Objective

5 Results Table 1. Summary of observed and calculated values for elbow, short bend and long bend fittings Fitting Measured Values Calculation Manometer Reading H1 (m) Manometer Reading H2 (m) Head Loss Δ H = H 1 − H 2 (m) Volume ∀ (Liters) Time t (sec) Flow Rate Q (m 3 /sec) Velocity V (m/sec) V 2 2 g (m) Loss Coefficient K Eqn [1] or [3] 1) Elbow 0.280 0.210 0.070 19 60 0.000317 1.395 0.099 0.705 2) Elbow 0.285 0.220 0.065 14.5 60 0.000242 1.065 0.058 1.125 3) Elbow 0.195 0.170 0.025 8.5 60 0.000142 0.624 0.020 1.259 1) Short Bend 0.154 0.110 0.044 19 60 0.000317 1.395 0.099 0.443 2) Short Bend 0.145 0.120 0.025 13 60 0.000217 0.954 0.046 0.538 3) Short Bend 0.150 0.130 0.02 8.5 60 0.000142 0.624 0.020 1.007 1) Long Bend 0.070 0.030 0.04 19 60 0.000317 1.395 0.099 0.403 2) Long Bend 0.095 0.065 0.03 13 60 0.000217 0.954 0.046 0.646 3) Long Bend 0.120 0.105 0.015 8.5 60 0.000142 0.624 0.020 0.755

8 Figure 3. Head loss (m) plotted against dynamic head (m) for enlargement and contraction fittings Figure 4. Loss coefficient K plotted against flow rate (m 3 /s) for elbow bend, short bend and long bend fittings

11 Discussion The lab data obtained from this experiment was combined with given lab data, due to the fact that some flow rates from the obtained data were nearly the same. So, when the head loss was plotted against the dynamic head and the loss coefficient was plotted against the flow rate, some data points were very close together while others were far apart. To better understand the data, some logical additions were made to the existing data so that when the graphs were plotted, the data points were spaced more evenly. 3) Comment on any relationships of Questions 1 and 2. What is the dependence of head losses across pipe fittings upon velocity? The head loss is proportional to the velocity of the fluid squared and the length of the pipe. It is also inversely proportional to the diameter of the pipe fitting. Also, the loss coefficient appears to decrease with increasing flow rates, as observed from Figures 4-7. The relationship between the head loss and dynamic head appears to be linear, looking at Figures 1-3. The r 2 values for those graphs are all greater than 0.75, suggesting that the linear trendline fits the data very well. Likewise, the relationship between the loss coefficient and the flow rate appears to be linear, looking at Figures 4-7. The r 2 values for those graphs are all greater than 0.75, suggesting that the linear trendline fits the data well. 4) Examining the Reynolds number obtained, are the flows laminar or turbulent? Looking at Appendix B, all the flows are turbulent (Re>4000). except for row 3)Contraction, where the Reynolds number is 3370 and is considered to be transitional flow (2300<Re<4000) (Engineering Toolbox, 2003). In this type of flow, turbulent and laminar flow characteristics can be observed. 5) Is it justifiable to treat the loss coefficient as constant for a given fitting? It is justifiable to treat the loss coefficient as a constant for a given fitting as it will not change during the time it takes to do this lab. The loss coefficient varies with velocity, flow rate, and head loss. Velocity, head loss and flow rates are subject to change.

14 Appendix B Table of Reynolds numbers for each fitting based on information from Tables 1&2 Fitting Reynolds Number 1) Elbow 23717 2) Elbow 18100 3) Elbow 10610 1) Short Bend 23717 2) Short Bend 16228 3) Short Bend 10610 1) Long Bend 23717 2) Long Bend 16228 3) Long Bend 10610 1)Mitre 24965 2)Mitre 6866 3)Mitre 4993 1)Enlargement 22719 2)Enlargement 18724 3)Enlargement 9986 1)Contraction 10610 2)Contraction 7240 3)Contraction 3370