It is important to note that the observed pressure head loss in these cases is due to both the minor loss in the object itself and a small amount of pipe friction. The biological growth, the obstruction and the encrustation are the most common forms of such deposits which can vary from 1 mm to 10 mm in thickness. The authors comment on this difference by the fact that the roughness coefficient which is the most important parameter might have not been suitably predicted. The length and inside diameter of the pipe were recorded. The experimental results obtained and their comparison to those computed using the relationships developed by diverse investigators over the last decades show a preponderance of the relations proposed by Darcy and Hazen-Williams. This lab includes the evaluation of head loss due to shear on pipe walls and minor losses due to an elbow and due to a valve. Data Reduction and Questions 1.
Within this intermediate region, the flow is complex involving both friction and turbulence, and it is difficult to separate the effects of the latter from that due to friction. Therefore it is recommendation are as follows: a. Analysis As shown in equation 6, minor head losses are expressed as functions of the velocity squared. Mostly used in the U. Total head is defined as the rate at which kinetic and potential energy are transported by the flow plus the rate at which the fluid does work against the internal pressure, all divided by the rate at which the weight of the fluid is being transported by the flow. The Nikuradse diagram also known as the Stanton diagram or the Stanton-Pannel diagram, is the result of these investigations. Its value is found to be 0095.
The authors feel that more interest should be given to this kind of local losses, and that future investigations should try to take into account all the factors involved in such head losses. Its value has in fact been chosen equal to that suggested by the manufacturer, thus neglecting the possible presence of deposits which generally tends to increase the roughness of pipe walls and consequently the head loss. The change in velocity produces large-scale. Use the speed controller and the main control valve to establish a steady flow. Close the stop-cocks on the manometer tappings.
The pump was switched on. Deformable wall materials are favored in alluvial soil conditions where seismic loading might be severe. The slope of that line will be f. Air bubbles were removed from the apparatus. Head Loss m h 1 -h 2 Calculated Head loss over the test section of the pipe.
Introduction When an incompressible fluid starts moving along streamlines, two basic laws get satisfied. Change to the new equipment and apparatus. The actual volume flow rate Q actual. These were all in 25mm galvanised steel pipe. Running low flow rate tests Repeat procedure given above but using water manometer throughout. Several explicit and implicit relationships were proposed for the friction coefficient. When outflow occurs from the header tank snap connector, attach the test section supply tube to it, ensuring no air is entrapped.
The errors found seem to be mainly due to the difficulty to determining the friction coefficient which is a function of the Reynolds number and wall pipe roughness. The second category called minor or singular head loss is due to the minor appurtenances and accessories present in a pipe network. Temp of °C Measured The temperature of the water collected. Setting-up for high flow rates The test rig outlet tube must be held by a clamp to ensure that the outflow point is firmly fixed. In one corner of the room, there is a 90 o elbow. You will need to use an appropriate friction factor from your analysis of 25mm galvanised steel pipe in the first part of the experiment major losses. Built the platform when taking the parallax error.
Step 6 to 8 for 5 values of Q actual were repeated. Note that a length of pipe between tapping points also contributes to the observed pressure loss. The water is pumped from reservoir to the pipes network through a closed circuit. Using your knowledge of manometers, demonstrate whether the difference in elevation of the pressure taps must be considered in reading the difference in manometer height to find the pressure drop caused by the fittings. Eight singularities widely used in distribution networks have also been investigated. They are presented in terms of the linear head loss versus the Reynolds number. One can use these two laws to check the behaviour of the dynamics of the fluid.
Procedure - Equipment Set Up Mount the test rig on the hydraulic bench and, with a spirit level, adjust the feet to ensure that the base plate is horizontal and, hence, the manometers are vertical. American Journal of Mechanical Engineering. The F1-1O Hydraulics Bench which allows you to measure flow by timed volume collection. This is measured with a manometer aboard the apparatus of this experiment. For low velocities, where the flow is laminar, friction loss is caused by viscous shearing between streamlines near the wall of the pipe and the friction factor f is well defined. Discuss how these values might change for different flow rates, Reynolds numbers, and pipe size diameter. .
This loss is mainly caused either by a diminution in the cross section area due to an accumulation of deposits inside the pipe, or an increase of the ruggedness, or both. Connect manometer tapping points immediately preceding each fitting under test to the left hand tube of each pair of manometers using the flexible tubing. The tubes are connected to a differential water-mercury manometer. In this experiment, we are going to measure the minor head losses through a section of pipe with a number of transitions, fittings and bends as shown in the figure below: The main purpose of this experiment is to study the head losses through common fittings and valves that are commonly found in piping systems. The Kinematic Viscosity of Water at Atmospheric Pressure can then be determined from the table provided.