Head loss due to pipe fittings lab report

Introduction And Method

INTRODUCTION (Student 2)

The introduction incudes several subsections:

1. Clearly present the objectives AND purpose of the experiment

· This section should discuss the importance of the subject in a specific manner, provide the background for the study, and give a clear statement of the objectives of the work. The objectives may include such items as testing a theory, determining the numerical value of some parameter, or better understanding a certain phenomenon. The reader should obtain a clear picture of the motivation underlying the experiment and a concise statement of what was to be accomplished. Students should avoid copying the objectives directly from the lab handouts; rather they should state these in their own words.

2. States a hypothesis and logical reasoning supporting the hypothesis

· This section should briefly discuss the theory underlying the experiment. The assumptions used in developing the theory should be identified and the validity of these assumptions assessed. All assumptions should be viewed with skepticism in order to lay the groundwork for later understanding and explaining discrepancies between theory and experiment.

3. List all equations (per format seen below) that were used to calculate results

· The governing equation(s) derived from the stated assumptions and application of the basic conservation laws should be given. Each variable and parameter must be defined unless previously defined in the discussion of assumptions. If appropriate, non-dimensional variables should be introduced, and their significance outlined. The solution of the governing equation(s) should be presented, if available.

METHODS (Student 2)

This section contains an overview of the experimental facility and procedure. Typically, schematic diagrams are used to illustrate the important features of the experimental apparatus such as key dimensions, placement of transducers, etc. The experimental procedure should be outlined, giving only enough information for another person to repeat the experiment. Step-by-step procedures, especially those copied or paraphrased from the laboratory write-ups, should NOT be given. Rather, a discussion should be presented only for those steps which are particularly difficult, which require a special technique, or which are relevant to understanding specific advantages or disadvantages of the approach. In addition, any problems or sources of experimental error that could influence the results should be noted.

Introduction (Alex Lerma)

The objective of this experiment is to test the theory behind momentum transfer as a function of deflection angle. The theory states altering the deflection angle to a certain degree can transfer twice the momentum. This test was done using a jet stream apparatus that would project water onto target of varying deflection angle. The momentum transferred from the jet stream nozzle would determine the time taken to fill a specific volume. We that as the deflection angle increases, the momentum transferred would increase. This hypothesis was taken when viewing and understanding the apparatus. As the angle of deflection of the target plate increases, gravity has a higher effect on the y component of the force. This is seen in the equations that drive the momentum transfer in this experiment. The y component of the theoretical force involves a, as the angle increases, this term becomes larger and larger, resulting in a higher y-component of force. This same theory can be supported when looking at the forces exerted by the jet stream. The basic equation used in this experiment is momentum balance is the sum of external forces (as shown in Eq. 1).

(1)

where is the sum of external forces (N), is the mass flow rate (kg/s), and is velocity (m/s). This sum of external forces can be separated into both the x and y components of the total force, and due to this a reference frame must be established. Figure 1 shows the reference frame used in this experiment.

ref frame (good).jpg

Figure 1- Reference frame used in the experiment

The jet stream apparatus is used to measure the theoretical force against a static loading. The apparatus is shown in Figure 2.

apperatus.JPG

Figure 2- Diagram of the apparatus used in the experiment [1]

As the fluid enters the inlet pipe, it is propelled out the nozzle towards the target plate. The fluid impacts the target plane and is then redirected towards the bottom of the apparatus. To establish static loading, the weight pan is loaded with mass until the pan is leveled with the level gauge while feeling the impact of the fluid. As the fluid reaches the bottom, a volume begins to fill up. This volume is used to measure the volume flow rate of the fluid exiting the nozzle. There are four different angles used for the target plane: 30, 90, 120, 180 degrees. Keeping the reference frame from Figure 1 in mind, the x-direction force can be stated as Eq. 2.

(2)

where is the deflection angle in degrees. Eq. 2 shows that the external force in the x-direction is equal to the momentum exerted multiplied by the sine of the deflection angle. The same basic idea is followed in Eq. 3

(3)

However, there a few assumptions to be made for Eq. 2 and Eq. 3. The first assumptions is that the mass flow rate is constant, as shown in Eq. 4.

(4)

thus,

where is the density (). The next assumption is made from Eq. 4. Eq. 5 shows that because the fluid is incompressible, the velocity must stay constant.

(5)

These assumptions are then applied to Equations 2 and 3, allowing them to become Eq. 6 and Eq. 7, respectively.

(6)

(7)

Methods (Alex Lerma)

The first step in this experiment is to calibrate the apparatus. The weight pan must be lined up horizontally with the level gauge before any flow is moving. Next, add a weight to the weight pan and slowly start the flow (using the bench flow control valve). As the flow impacts the target plate, the weight pan must once again be leveled with the level gauge. Once these components are lined up, measure the volume of the fluid as it enters the volume using a stopwatch. Pick a specific volume to measure too and record the time once the volume is at that mark. Measure for at least one minute to decrease in time errors. To obtain more consistent measurements, repeat this three times and average the times. After this is completed, repeat this experiment at each deflection angle using four different weights for each angle (totaling 48 trials). The resolution of the volume is 1 liter and the resolution of the stopwatch is 1 second. This experiment is simple to conduct and allows for consistent results. Taking three trials for each weight at each angle allows for experimental errors between the readings to decrease. The biggest discrepancy in this lab may be getting precise readings to create a low range