Lab 6 Report

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Apr 3, 2024

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Lab #6 - Energy losses in pipe bends CE 336 – Fluid Mechanics Lab Instructor: Andres Acosta, MS, PE Group Members: Macias Silva, Salvador Date of Lab: 10/12/22 Date Submitted: 11/09/22

Introduction For this lab, the goal was to demonstrate the minor loss of the fluids flowing in the pipe bends. By doing this lab, we can observe how the pipe fittings and flow rates affect the minor loss coefficients. To begin, the control valve was set to read all the different manometers. Next, the time was collected when 5 liters of water were collected. Set the bench controls to a different level after the reading was done. This data resulted in flow rate, velocity, and loss coefficient calculations. On the other hand, for the second section of the lab, the flow control valve was set in one constant level, but the only thing changing was the gate valve that differed from fifty to seventy to eighty percent of a complete turn. With this data, we were able to see the loss coefficient in the opening of the valve. Purpose of Study Throughout the experiment, the purpose was to understand minor losses for different pipe fittings as well as the flow rates for different pipe fittings. Theory The energy lost through the fluid flows of a pipe is known as major and minor losses. Minor losses are due to the loss of pipe fittings. These minor losses can be calculated by the formula. ∆ (1) ℎ = 𝐾 𝑉 2 2𝑔 V represents the velocity through the pipe. As for K, it's dependent on the type of pipe fittings. The second equation can also find K. K = (2) ∆ℎ 𝑉 2 /2𝑔

By taking the manometer reading before and after the pipe fitting, the head loss (∆h) can be experimentally found. As for pipe expansion loss, it can be calculated with the equation. (3) ℎ 𝑒𝑥𝑝 = (𝑉 1 − 𝑉 2 ) 2 2𝑔 To eliminate the effect of cross-sectional area in the pipe, the additional loss should be added to the measured head loss for pipe expansion or contractions. Equipment The equipment used during the experiment included: ● F1-22 Armfield apparatus ● Hydraulic bench ● Mitre bend ● Elbow bend ● Short bend ● Area enlargement ● Area contraction ● Stopwatch Experimental Set-Up & Procedures Begin by opening the water valve, gate valve, and flow control valve on the hydraulic bench. Next, stabilize the water level and record all the monometer readings for the given flow rate. By collecting 5L of water and recording the time it takes to reach that level, you will find the flow rate. Lastly, repeat the procedure for different flow rates ranging from 8 to 17 liters per second for 5 sets. For the second experiment, make sure to keep the gate valve closed. Second, open the valve for the hydraulic bench as well as the flow control valve of the apparatus. Then

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do a half turn and turn on the pump. Similarly, collect 5L of water in order to find the flow rate and measure the pressure drop across the valve. Then adjust the flow control to set different flow rates. Continue by repeating step one, but this time turn open the gate valve for about 70% and take 5 sets of readings for the flow rate and the pressure drop in the valves. Lastly, repeat one more time with about 80% of a turn and record the 5 sets once again. Calculations Velocity: Flow Rate Q/Area (1.5 e^−4) /(π/4 ∗ 0.0183^2) =0.570 Loss Coefficient: K= delta h / V^2/2g (.014) /((0.570^2)/ 2 ∗ 9.8) = .85 Reynold’s Number: V*D/v (0.570 ∗ 0.0183)/(1.002 e^−6) = 10410.2 Discussion

Questions 1. Why fluid losses energy when flowing through various pipe fittings? ● Fluid flows tend to lose energy in the pipe fittings when the streamlines are not straight. This occurs from the viscosity as well as the fitting geometry. 2. When is it ok to ignore minor losses? ● Minor losses are ok to be ignored when working with an open valve, under turbulent flows, or when the pipe length is too long that major losses are greater than minor losses. Conclusion Throughout the experiment, the purpose was to understand the minor losses caused by differences in pipe fittings and the variable flow rates. During experiment one, it was noted that head loss was much dependent on the pipes velocity flow. A lower velocity was shown to give less head loss, and a higher velocity resulted in more head loss. On the other hand, it was noted

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that the loss of (K) was a constant value tied to a respective fitting. As a result, in the sharper turning edges, there was more energy lost compared to the more gradual turning radius. In experiment two, when the valve was opened further, it showed a decrease in the loss of the coefficient. When opening the valve, 50% compared to 80%, was shown how the reduction of energy loss was much greater. References Sultana, Rebeka. "Lab #6 Energy losses in pipe bends." Fluid Mechanics Laboratory Student Manual . 2017. Print.