Fluid Mechanic Lab - Reynold's Number Experiment
6 likes12,352 views
1. The document summarizes an experiment conducted by Muhammad Sulaimon Rasul to determine different types of fluid flow (laminar, transitional, turbulent) using Reynolds apparatus. 2. The experiment measured the volume of water and time taken to fill a graduated cylinder for different flow rates. This was used to calculate Reynolds number to identify flow type. 3. All results showed Reynolds numbers less than 2000, indicating laminar flow for all trials according to the theoretical boundaries between flow types.
Fluid Mechanic Lab - Reynold's Number Experiment
- 1. Soran University Faculty of Engineering Department of Petroleum Engineering Fluid Mechanic Title: Reynolds Experiment Experiment No.: 4 Name: Muhammad Sulaimon Rasul Group: B2 Date: 22 OCT 2019 Supervisors: Ms Marriam, Mr. Shahab, Mr. Sarkar
- 2. Contents Aim………………………………………………………………………………………….…….1 Theory…………………………………………………………………………………….…….…1 Apparatus…………………………………………………………...…………………………..…3 Procedure………………………………………………………………………………………….4 Calculation………………………………………………………………………………...………5 Result and Discussion……………………………………………………………………………..6 Conclusion………………………………………………………………………………………...6 References…………………………………………………………………………………………7 List of Figures Figure 1. Type of Fluid Flows ………………………...………………………………………….2 Figure 2 Blue Ink…………………………………………………………………..……..……….3 Figure 3 Reynold Apparatus………………………………………………………………………3 Figure 4 Graduated Cylinder ……………………………………………………………………..3 Figure 5 Timer…………………………………………………………………………………….3 List of Tables Table 1: Experimental and Theorical Results……………………………………………………..6
- 3. Aim The objective is to determine: 1. The flow type (laminar, transitional, or turbulent) of fluid inside a pipe line. 2. At which condition each type of flow can occur. Theory In the 19th century, the “Reynolds Number” was given to “Osborne Reynolds”, in which performed an experiment that illustrate two different types of flow. He used to inject a thin stream of colored fluid into a long water flowing glass tube. Reynold noticed that if the volume and dimeter or both are small and the viscosity is large; Re will be small and in this case the fluid flow becomes laminar. Increasing dimeter or volume or decrease the viscosity cause Re to increase (Taneda, 1956). The fluid flow in a pipe line (closed conduit) is differ from a fluid flowing in open channel where a closed channel is at a pressure. Which a flow in a pipe line can be illustrated such as; Laminar, Transitional, and Turbulent flow. To differentiate between above features, known as “Reynold’s Number” can be used in order to make a good distinction. Reynold gave a number that can be used as a boundary of flow faces which is a function of; fluid density, fluid viscosity, pipe diameter, flow velocity (Jaafar, 2019). The flow regimes are made visible colored sight which able to provide and illustrate the velocity image as (Figure 1), when a sight tracer appears as a straight line the flow is laminar as (Figure. 1.a) as soon as the flow rate changes the straight line to a turbulent which tracer spread inside the pipe cross-section (Figure 1.b) (Mattioli, 2008). According to Osborne Reynolds, If the value of Re<2000 then the flow is laminar while Re is between 2000- 4000 it used to be a transitional and if Re>4000 it said to be Turbulent (Jaafar, 2019). NRe= vDρ/μ or R = vD/υ ………………………………………………………..………..………(1) Cross-Section Area: 𝐴 = 𝜋𝑟2 …………………………………………………………………...(2) Flow rate: Q = V/t ………………………………………………………………………………..(3) Velocity: v = Q/A ………………………………………………………………………………..(4) 1
- 4. Where: NRe = Reynolds No dimension less ; μ = Dynamic viscosity, for water: 0.008817 kg/m.s ; υ = Kinematic viscosity m2/s, for water: 10-6 m2/s ; V = Volume in m3 ; D = Diameter of pipe in m ; A = pipe area m2 ; ρ = Density kg/m3 ; t = time in seconds ; Q = flow rate in m3 /s. Figure 1. Type of Fluid Flows. In (a) the flow is laminar. In (b) the flow is turbulent. In (c) the transition from laminar to turbulent motion is seen in detail, with the formation of curls in the tracer before the mixing with the other fluid becomes complete (Mattioli, 2008). 2
- 5. Apparatus and Materials Materials: • Water. • Blue Ink: Is a martial used to indicate and show type of flow in a water which has a different density. Shown at Figure 2. Apparatus: • Reynolds Apparatus: Is a device used to show and determine type of flow of a fluid in different flow rates. See Figure 3. • Graduated Cylinder: Used to determine the volume of water. Shown in Figure 4. • Stopwatch: Used to determine flowing time to the graduated cylinder. See Figure 5. 3 Figure 2. Blue ink. Figure 3. Reynolds Apparatus Figure 4 Graduated cylinder. Figure 5. Stopwatch
- 6. Procedure 1. Fill the ink tube with blue ink. 2. Now lower the ink injector till it seen in the glass tube. 3. Connect the water tank to a water source to making sure that the water level stays constant in water tank. 4. Now open the water valve with dye valve and let the ink or dye leak to the glass tube until the slow flow is achieved. 5. Bring a graduated cylinder and set a timer when a cylinder gets filled with water. 6. Let a cylinder filled in water to any volume while the timer is running. 7. Stop the timer with closing the outlet valve. 8. Record the time and volume of water in cylinder. 9. Repeat the same procedure 5 more times for different type of flow by controlling the valve. 4
- 8. Result and Discussion Table 1: Experimental and Theorical Results. Trail No. Volume of Water (cc) Time (sec) Volumetric Flow Rate (m3/s) Reynold’s No. Flow Type 1 85 6.08 1.39x10-5 146.88 Laminar 2 105 2.81 3.73x10-5 415.81 Laminar 3 70 11.18 6.26x10-5 70 Laminar 4 135 7.06 1.912x10-5 212.78 Laminar 5 107 10.28 1.04x10-5 115.82 Laminar 6 109 6.81 1.6x10-5 178.11 Laminar Regarding to the (Table 1.) each trail number has measured its volume at a certain period of time using a timer and graduated cylinder. The calculation for volumetric flow rate has to be first calculated using Equ.3. while the volume has changed to m3 from a cubic centimeter. The Reynold No. can be calculated using Equ.1. by putting the value of each density of water in kg/m3, µ of water, diameter of tube, and the fluid velocity which can be calculated from Equ.4. by dividing the flow rate over the cross-section area of the tube using the Equ.2. And the fluid types can be recognized using Reynold number range of fluid types which the results were NRe less than 2000 that indicates that all fluids have laminar trace. Conclusion Reynolds number indicates that the type of fluid flow can take three form of Laminar, Transitional, and Turbulence depending on the density of the fluid, viscosity, pipe diameter, and flow velocity. Which can be experimentally tested on Reynolds apparatus. 6
- 9. References Franco, M. (2005). The Reynolds experiment Chapter 13. Bologna: University of Bologna, pp.97- 99. Maatooq, J. (2019). Flow Dynamics in Closed Conduit (Pipe Flow). uotechnology.edu.iq, pp.1-2. Sadatoshi Taneda, (1956): Experimental Investigation of the Wake behind a Sphere at Low Reynolds Numbers; Journal of the physical society of japan, vol. 11, no. 3, pp. 1104-1108. 7