You will see that for the major losses, each pipe had three different flow rates passed through it. Water is pumped up to a header tank through a ball valve A so that a constant head is provided for the laminar flow experiment. 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. Introduction The flow of fluid in a pipe under pressure is used to reach many goals. Close the stop-cocks on the manometer tappings.
The changes in water pressure, through the different pipe types, is measured at the end of the rig. Air bubbles in any of the pressure lines will lead to gross errors in your data. Lastly, the less surface contact between an object and a surface, the less force needed to move the object. Our final experiment was to see how the yeast would transmit if we did wash our hands. For the most accurate measurements, the timing should be made between two mass values. Aim This lab could be used in industry when dealing with a pipe line containing any type of liquid to calculate the Reynolds number and friction factor. A further test pipe is artificially roughened and, at the higher Reynolds' numbers, shows a clear departure from typical smooth bore pipe characteristics.
On its back, μs was 0. The results obtained through the different singularities investigated are resumed in. When finished, exit the program. In mechanical systems such as internal combustion engines, it refers to the power lost overcoming the friction between two moving surfaces. Note: Error Bars represent standard deviation. Once the object is in motion, cold-welds cannot form so therefore force is not needed to break them as in the case of a static object. To disconnect a test probe from a pressure point, press the metal clip of the side of the pressure point to release the test probe.
Except enlarger and reducer other section has no velocity change therefore the head loss due to velocity is zero. The presence of boundary layer due to friction creates major flow in pipes. Equipment In order to complete the demonstration we need a number of pieces of equipment. The water then flows from the outlet pipe of the header tank to the pipe friction test bench through another ball value B. In the first part, we applied the principle of pressure difference across fittings in a closed conduit to find out the loss coefficients of these fittings.
In the case of a sudden enlargement for example, the re-establishment of the velocity field takes a distance of approximately 100 the pipe diameter. The second category called minor or singular head loss is due to the minor appurtenances and accessories present in a pipe network. To understand how this works we must understand two terms. If the pipe is of uniform cross-section and roughness, and the flow is fully developed, that is if it is sufficiently far from the inlet of the. The head loss in a pipe is divided in to two main categories. Plot graphs for log f against log Re and compare with the Moody diagram.
Record these values on Table 1. Before an object can move over a surface, these cold-welds must be broken. For turbulent flow, the pressure drop is dependent on the roughness of the surface, while in laminar flow, the roughness effects of the wall are negligible. If required these values may be checked as part of the experimental procedure and replaced with your own measurements. Then you will compare the absolute roughness k with typical roughness values for each pipe material you can find such values in textbooks or on the internet. 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. The shift from laminar flow to turbulent flow is seen from the results recorded, but it is observed more clearly from the water-soluble dye experiment that was carried out by the demonstrator.
For laminar flow, the exact theory for the friction factor results in an expression which is independent of relative roughness, 3 For fully turbulent flow, an adequate expression for friction factor is more difficult to determine from theory. The constant head is maintained by means of an overflow tube in the header tank. Note that a length of pipe between tapping points also contributes to the observed pressure loss. In general, a very sudden change to the flow path contributes to significant pressure loss. Label and attach your figure to this report. It was difficult to maintain a steady speed to measure μk.
Values of f can be determined experimentally and plotted in dimensionless form against Reynolds Number Re to from a Moody Diagram. Gallery Different types of pipes create different amounts of friction thereby impacting on the flow rate. Different parts of the piping systems like straight pipe, elbow, bend, valves, are considered in the lab report and each analysis for the minor loss friction is also performed. In operation, the volumetric tank is emptied by lifting the dump valve, allowing the entrained water to return to the sump. Introduction: Force is usually connected with a push or pull exerted on an object.
The instrument panel includes a pressure gage and pump control valve. The head is measured in mm. The pressure drop in a pipe is mainly due to friction and the value is directly proportional to the friction factor f. As increasing the average of velocity, the pressure losses will increase too. Great difficulties have been faced by the authors when dealing with minor losses. The head loss reading is recorded directly by the data acquisition system. The aim of this experiment is to investigate the pressure drop in a pipe due to surface roughness.