Laboratory #2 - Supplemental Guide (1)

pdf

School

Palo Alto College *

*We aren’t endorsed by this school

Course

4312

Subject

Mechanical Engineering

Date

Apr 3, 2024

Type

pdf

Pages

Uploaded by LieutenantBookOpossum46

ME 4312 - Thermal and Fluids Laboratory | Page 1 of 6 The University of Texas at San Antonio (UTSA) Klesse College of Engineering and Integrated Design Department of Mechanical Engineering ME 4312 - Thermal and Fluids Laboratory Laboratory Assignment #2: Analysis of a Pipe Network Supplemental Guide Experimental Procedures: In this lab you will be testing 11 different sections of the pipe network. This includes 3 smooth pipes (you will not test the small 4-mm pipe), 1 rough pipe, 3 radius bends, miter corner, elbow bend, and a sudden enlargement and contraction (you will not test the second expansion). Each of these will need to be tested for 5 different flow rates. The piezometer is capable of connecting to 3 pipe sections at once. Make sure you only test one circuit color at a time; thus, you can test 3 sections at once if they share the same circuit. In addition, taps 18 and 19, used for 2 of the radius bends, share a port that is controlled by a small valve. Both bends can be tested together, but when connecting or disconnecting them you will need to turn this valve to the tap you are using, as shown in Figure 1. This also needs to be done when taking readings off the piezometer. Figure 1. Turn the valve to the measured tap. Figure 2. Close caps on Schrader valves. To start connecting the sections of the pipe network to the piezometer, first inspect the piezometer to make sure the caps on the Schrader valves are closed fully (do not over tighten). See figure 2. Then make sure that all 3 valves (the ball, globe, and gate) are CLOSED! There should be no water flowing into the water bench when connecting or disconnecting the piezometer. Take two of the hoses, put one end into the orange bucket and connect to the board first. Water will flow into the bucket. See figures 3 and 4. Figure 3. Put one end in water receptacle . Figure 4. Connect hose to board. Quickly take the two ends from the bucket and connect them, at the same time, to the piezometer (make note of which hose is upstream and downstream). See figure 5. If you don’t connect at the same time water will reach the bulb with the Schrader valve and you will be forced to drain the piezometer. Make sure the black pan is under the piezometer to catch most of the water. If you do this right, the water should read a 0 difference as shown in figure 6.

ME 4312 - Thermal and Fluids Laboratory | Page 2 of 6 Figure 5. Connect ends to piezometer. Figure 6. Proof that you did it correctly. Now you can open the valve for the circuit you wish to test. Once you do, the water level in the piezometer will change, as shown in figure 7. Have a group member call out the two water levels for someone to record. If the water drops below 0 on the piezometer, inform your TA. Figure 7. Water level changes on piezometer. While one group member reads the piezometer, another should do the measurement of flow rate. To measure flow rate, a cylindrical plug located in the water bench is dropped into a hole to allow the upper reservoir to flood, as shown in figure 8. A gauge on the front of the bench will indicate how much water is in the upper reservoir. See figure 9. The manual tells you to record the time it takes to fill 18 liters; however, it can be any volume. The suggestion to reduce efforts is to record the time it takes to fill 5 liters instead (18 or 15 liters can take too long for low flow rates). Also, do not start timing until the reservoir fills up enough to read 0 on the gauge. You can use your cell phone as timer. Figure 8. Plug in water bench. Figure 9. Water gauge.

ME 4312 - Thermal and Fluids Laboratory | Page 3 of 6 The 3 valves in figure 10 control the flow through the network. Again, only one should be open at a time. The ball valve can be turned 90 degrees, but at around 50-60 the flow rate through the valve is already at its max. Opening the valve further doesn’t do anything. The other two valves have the same issue; if you open the valve further and notice that you are getting the same time to fill 5 liters, then you need to throw that data point out and close the valve to get a different flow rate. Figure 10. Water level changes on piezometer. Once you have the readings for the 5 flow rates, close all valves and then disconnect the hoses from the pipe network and throw the ends into a receptacle . Leave the hose connected to the piezometer for now. Remove the cap from the Schrader valve (don’t lose it), attach the pump to it, and pump the water out of the piezometer. See figure 11. Once you have nothing but air coming out of the hose, replace the cap on the Schrader valve and disconnect the hoses from the piezometer. You can now start connecting to other parts of the pipe network for testing until finished. Empty the water from the receptacle into the water bench (see figure 12) and mop up any water on the floor when done. Figure 11. Plug in water bench. Figure 12. Water gauge.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

ME 4312 - Thermal and Fluids Laboratory | Page 4 of 6 Theoretical Data: Theoretical formulations and information can be found in: (1) the lab manual and (2) your notes from Fluid Mechanics, Thermodynamics I, and Heat Transfer (review the course schedule for information on textbook chapters). Important formulations for the theoretical section are: (a) viscosity in Newtonian fluids, (b) pressure drop and head loss in internal flows (laminar or turbulent, circular or noncircular pipes, smooth or rough surfaces). Simulation Data: Below suggestions for the simulation component of this laboratory assignment: 1. Select 3 representative experiments of all the experiments conducted in the lab. That is, experiments where you measured pressure differences with the piezometer. 2. Create a CAD of "the portion" of the pipe network where the aforementioned experiments were conducted (do not attempt to simulate the entire network, it is very difficult!). See the following video to learn how to draw pipes in SolidWorks (courtesy of O'Reilly - Video Training): https://www.youtube.com/watch?v=nuRPKYVnBTs 3. Simulate the pipe flow using the same conditions as in the lab (e.g., volumetric flow rate) and by following the steps presented in the following video (courtesy of Innova Systems): https://www.youtube.com/watch?v=xyU5Yvg7gL8 4. Collect relevant simulation data that can be compared with experimental and theoretical data. Summary of Findings: The following is a checklist of what should appear in the “data analysis” section of your report. None of this information is new or different from what was asked in the manual. It is simply included here in a list with some clarification based on common questions. Your “data analysis” section should be written in report form, not as responses to the checklist. The checklist should be used only to guide your discussion. Losses in Straight Pipes  Prepare tables with the data provided on Blackboard for losses in straight pipes and include the following (as in Table 2, pg. 15, Condensed Manual): o Flow rate, Q o Difference of upstream and downstream Piezometer readings ( Δh ) o Flow velocity, u o Reynolds number, Re o Friction factor, f o Blasius friction factor, Blasius f  Discuss the tables. • For smooth pipes: o Use Reynolds number to compare the pipes of different diameters for different flow rates. o Compare Blasius friction factor to friction factor f . Do these values suggest that the pipes are perfectly smooth? o What effect does the pipe diameter have on apparent smoothness? o Does the fluid flow through smooth pipes correspond with the theory? • For roughened pipe: o Compare f factor to value obtained from Moody chart. o Comment on how the values change for different flow rates. o Does the fluid flow through the roughened pipe correspond with the theory?

ME 4312 - Thermal and Fluids Laboratory | Page 5 of 6 Losses in Bends  Prepare tables with the data provided on Blackboard for losses in bends and include the following (as in Table 3, pg. 20, Condensed Manual): o Flow rate, Q o Difference of upstream and downstream Piezometer readings ( Δh ) o Flow velocity, u o Reynolds number, Re o Modified Blasius friction factor, Modified Blasius f (pg. 21, Condensed Manual) o Straight Pipe Loss, h (from 1 st equation on pg. 16, Condensed Manual) o Bend loss (head loss due to bend geometry), h B (demonstrated on pg. 22, Condensed Manual) o u 2 /2g o Total Loss coefficient, k L (demonstrated on pg. 22, Condensed Manual)  Plot graphs (for each bend) of h B vs. u 2 /2g, using the data for each bend. Find the slope of each line to determine the k B value for each bend.  Plot a graph of k B vs. R/d to compare all bends. Use an R/d value of 1 for the elbow and 0 for the mitre bend, since R values were not provided for these fittings.  Discuss tables and plot. o What effect does the bend radius have on energy loss? o What causes the energy losses in bends? o Are bends as perfectly smooth as pipes? o If you were designing a piping system with 13.6 mm inside diameter pipe, and wanted to reduce losses due to bends, what would you set as the minimum bend radius? o Standard graphs of k L vs. R/d (pg. 22, Figure 16, Condensed Manual) show that k L has a minimum value at R/d of between 2 and 3. Why do you think this is? o Which value, k B or k L , do you think is of most practical use? Why? Sudden Expansion and Sudden Contraction  Prepare tables with the data provided on Blackboard for sudden expansion and contraction and include the following (as in Tables 4 & 5, pg. 24 & 25, Condensed Manual) o Flow rate, Q o Difference of upstream and downstream Piezometer readings ( h m ) o Upstream velocity, u 1 o Downstream velocity, u 2 o Head Rise due to Velocity change, h u o (u 1 -u 2 ) 2 /2g (for expansion) o Head Loss due to Expansion/Contraction, h L o Head rise due to velocity minus measured head rise, – (h u -h m ) (for expansion) o Combined head loss (h L + h u ), h Total (for contraction) o Measured head loss minus head loss due to velocity change, (h m -h u ) (for contraction o u 2 /2g (for contraction)  Plot a graph of head rise due to velocity minus the measured head rise (h u -h m ) vs. (u 1 -u 2 ) 2 /2g , and find the slope. This gives k L for expansion case.

ME 4312 - Thermal and Fluids Laboratory | Page 6 of 6  Plot measured head loss minus head loss due to velocity change ( h m -h u ) vs. u 2 2 /2g , and find the slope. This gives k L for contraction case.  Discuss the tables and plots. o Comment on the head rise across the expansion. o From what principal equations is the head rise, h u , derived from? o Comment on the head rise due to velocity change across the expansion, h u , for the different flow rates/velocities. o Comment on the head loss/head rise across the expansion, h L . o Comment on the value of k L and its significance for expansion. o Comment on the head loss due to the velocity change across the contraction. o Is the sudden contraction the same theory as expansion but in reverse? Why or why not? o Comment on the significance of k L for contraction.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version