In the experiment described below, we investigate the frictional resistance to flow along a. Minor losses local pump tee valve outlet elbow inlet pipe b vena contracta flow separation at corner separated flow separated flow q pipe entrance or exit sudden expansion or contraction bends, elbows, tees, and other fittings valves, open or partially closed gradual expansions or contractions. This is the head loss caused by pipe wall friction and the viscous dissipation in flowing water. The specific hydraulic model that we are concerned with for this experiment is the energy. In some cases, minor losses may be greater than major losses cengel and cimbala 2014. This loss can be calculated using the moody chart or colebrook equation. Minor in comparison to friction losses which are considered major. If the pipe is long enough the minor losses can usually be neglected as they are much smaller than the major losses. These additional components add to the overall head loss of the system. Major head losses in pipe flow problem will be calculated with the help of darcyweisbach formula as mentioned below and this darcyweisbach formula will be used to calculate the major loss in pipe flow, it does not matter that pipe is horizontal, vertical or on inclined plane.
Two types of energy loss predominate in fluid flow through a pipe network. However, pipe systems usually consist of many other components, such as valves, bends, elbows, expansions, etc. The overall head loss for the pipe system consists of the head loss due to viscous effects in the straight pipes, termed the major loss and denoted hlmajor. Such losses are generally termed minor losses, although they often account for a major portion of the head loss. Frictional losses major losses usually are responsible for the majority of the pressure losses in a pipe system. Major and minor losses can substantially affect the effectiveness and efficiency of a given fluid transport system. These minor losses cause nonuniformities in the flow path, resulting in small energy losses due to. Empirical data on viscous losses in straight sections of pipe are correlated by the dimensionless darcy friction factor f. Frictional head losses are losses due to shear stress on the pipe walls.
Jun 30, 2017 pressure drop in pipe with losses determine pressure drop duration. Head losses in pipes penn state mechanical engineering. Losses are proportional to velocity of flow, geometry of device 2 h k v g 2 l. In case of a long pipeline, the minor losses maybe negligible compared to the friction losses, however, in the case of short pipelines, their contribution may be significant. There are many types of losses of head for flowing liquids such as friction, inlet and outlet losses. Example lab report losses civl2310 fluid mechanics.
To find the major losses throughout the system, a technovate fluid circuit system was used. These losses are usually known as minor losses hlm. The major loss is that due to frictional resistance of the pipe, which depends on the inside roughness of the pipe. The knowledge of data of such transformation allows the determination of the necessary power needed for the transportation of the.
Energy equation pressure head loss in ducts, tubes and pipes. Major head loss head loss or pressure loss due to friction in pipes and ducts. Major losses are formed in long length pipes and are due to the head loss in the straight sections. Major losses the major head loss in pipe flows is given by equation 3. Recognize the distinction between major losses and minor losses in a pipe system, 2. Evaluation of friction losses in pipes and fittings of process engineering plants f. For a long pipeline, on the other hand, skin friction at the pipe. Additional components valves, bends, tees, contractions, etc in pipe flows also contribute to the total head loss of the system. The pressure losses across two sections of pipe, with inner diameters of 0. The general equation for head loss due to friction is the darcyweisbach equation, which is where f darcyweisbach friction factor, l length of pipe, d pipe diameter, and v cross sectional average flow velocity. Friction loss along a pipe introduction in hydraulic engineering practice, it is frequently necessary to estimate the head loss incurred by a fluid as it flows along a pipeline. For relatively short pipe systems, with a relatively large. Major losses are associated with frictional energy loss that is caused by the viscous effects of the medium and roughness of the pipe wall.
Example lab report losses civl2310 fluid mechanics uon. The friction factor for laminar flow is independent of roughness of the pipes inner surface. Energy losses when a fluid is flowing through a pipe, the fluid experiences some resistance due to which some of the energy of the fluid is lost. Pdf method for determining friction head loss along. May 05, 2020 major losses occur due to friction within a pipe, and minor losses occur at a change of section, valve, bend or other interruption. Pdf method for determining friction head loss along elastic.
Major and minor losses in pipes mechanical engineering. Minor head loss due to components as valves, bends darcys equation can be used to calculate major losses. Materials and methods major losses to find the major losses throughout the system, a technovate fluid circuit system was used. Energy losses in pipes used for the transportation of fluids water, petroleum etc. M6 head losses major losses minor losses example problem total head loss friction loss extended bernoullis equation in the analysis of piping systems, pressure losses are commonly expressed in terms of the equivalent fluid column height called head losses h l. Losses are proportional to velocity of flow, geometry of device.
The apparatus was designed such that major and minor losses through a piping system could be determined for turbulent flow. Hazenwilliams equation, originally developed for the british measurement system, has been writtten in the form 1. In pipes, major loss in straight sections is caused by friction and minor loss is caused by fittings, both resulting in a drop in pressure. Friction loss along a pipe introduction in hydraulic. Head loss in pipe flow system due to viscous effect i. What is major minor losses in a flow through pipe answers. Energy lost due to a change in velocity inside of a fitting or valve is generally small in comparison to major losses, and is commonly referred to as minor. May 15, 2018 losses due to the local disturbances of the flow in the conduits such as changes in cross section, projecting gaskets, elbows, valves and similar items are called minor losses. These losses are usually converted into head reductions in the direction of the flow. Energy loss through friction in the length of pipeline is commonly termed the major loss hf which is the loss of head due to pipe friction and to viscous dissipation. This is different from major losses because those come from friction in. Liquid moving through pipes carries momentum and energy due to the forces acting upon it such as pressure and gravity.
Major head losses are dependent on the friction factor, and the friction factor is dependent on the reynolds number allen 1973. The impact of flow rate q on the head loss h l in pipes and fittings was studied on different sizes or diameters d of pipes fitted with gate valve, 45 and 90o bends using water as process fluid. In other cases the minor losses are greater than the major losses. For example, it may be desired to predict the rate of flow along a proposed pipe connecting two reservoirs at different levels. The head loss in various pipe components, termed the minor loss and denoted hlminor. Chapter 7 flow through pipes 71 friction losses of head in pipes 72 secondary losses of head in pipes 73 flow through pipe systems 71 friction losses of head in pipes. Major losses occur due to friction within a pipe, and minor losses occur at a change of section, valve, bend or other interruption. The objective of this experiment is to measure the effects that pipe diameter have on the friction factor, or major losses, and the effects that various fittings have on the minor losses in pipes.
Minor head loss due to components as valves, fittings, bends and tees. Major and minor losses due to pipe diameter and fitting. The total energy per mass unit in a given point in a fluid flow consists of elevation potential energy, velocity kinetic energy and pressure energy the energy equation states that energy can not disappear the energy upstream in the fluid flow will always be equal to the energy downstream in the flow and the energy loss between the two points. Minor losses local pump tee valve outlet elbow inlet pipe b vena contracta flow separation at corner. Friction losses are a complex function of the system geometry, the fluid properties and the flow rate in the system. Friction head losses in straight pipes of different sizes can be investigated over a range of reynolds numbers from 103 to nearly 105, thereby covering the laminar. Minor losses in pipes losses caused by fittings, bends, valves, etc. Experiment image and source credits minor loss in pipe or duct components. This is different from major losses because those come from friction in pipes over long spans. Even though they are termed minor, the losses can be.
Pdf modification of setup for major losses in pipes to determine. Head losses in pipes pennsylvania state university. In this practical you will investigate the impact of major and minor losses on water flow in pipes. Minor losses in pipes come from changes and components in a pipe system. You created this pdf from an application that is not licensed to print to. The major head loss for a single pipe or duct can be expressed as. Compare the experimental results to the published moody chart or colebrook equation. Head loss in pipe flow major and minor losses portland state. Major head loss due to friction in pipes and ducts.
Just as certain aspects of the system can increase the fluids energy, there are components of the system that act against the fluid and reduce its energy. Hazenwilliams equation, originally developed fort he british measurement system, has been writtten in the form 1. The overall head loss for the pipe system consists of the head loss due to viscous effects in the straight pipes, termed the major loss and denoted hl major. By observation, the head loss is roughly proportional to the square of the flow rate in most engineering flows fully developed, turbulent pipe flow. Just as certain aspects of the system can increase the fluids energy, there are components of the system that. Basic fluid mechanics major losses, colebrookwhite equation. Minor losses in pipe flow are a major part in calculating the flow, pressure, or energy reduction in piping systems. A pipe losses most pipe systems consist of considerably more than straight pipes. The minor losses are greater than the major losses and are raised by 1. Minor head loss head loss or pressure loss due to components as valves, bends, tees and the like in the pipe or duct system. Losses due to the local disturbances of the flow in the conduits such as changes in cross section, projecting gaskets, elbows, valves and similar items are called minor losses. Such losses are generally termed minor losses, with the apparent implication being that the majority of the system loss is associated with the friction in the straight portions of the pipes, the major losses or local losses. For laminar flows, which occur less frequently, the equation for the minor losses is k va. In industry any pipe system contains different technological elements as bends, fittings, valves or heated channels.
Energy losses in pipe flow major energy loss due to friction minor energy losses a. Pdf minor losses in pipes venkitaraj konery purushothaman. Pdf in this research paper we determine the exact value of friction factor through pipes for turbulent flow. Energy losses in pipes used for the transportation of fluids water, petroleum, gas, etc. If we know the reynolds number and the roughness the friction coefficient. Major losses, colebrookwhite equation, jain equation.
As can be seen, the head loss of piping system is divided into two main categories, major losses associated with energy loss per length of pipe, and minor losses associated with bends, fittings, valves, etc. Head loss in pipe flow system due to various piping components such as valves, fittings, elbows, contractions, enlargement, tees, bends and exits will be termed as minor head loss and will be indicated by h lminor. Jun 10, 2015 frictional head losses are losses due to shear stress on the pipe walls. In general, the friction factor is a function of the reynolds number and the nondimensional surface roughness, ed. Major losses are typically head losses in straight pipe sections, while minor losses are head losses within long pipes. Reinforce concepts of the moody chart, and of major and minor head losses in pipes. If there were no friction in the pipe, the head loss would be zero. Energy lost due to a change in velocity inside of a fitting or valve is generally small in comparison to major losses, and is commonly referred to as minor losses. Measure the friction factor for pipes of various diameters and roughnesses. The value of k is typically provided for various devices. Pressure drop in pipe with losses determine pressure drop duration. Method for determining friction head loss along elastic pipes article pdf available in irrigation science 325. For a long pipeline, on the other hand, skin friction at the pipe wall will predominate. For the major losses, the volumetric flow rate was computed by using the equation.
1407 1634 1303 1021 759 667 955 32 1510 1522 1194 1154 1097 536 616 205 588 1203 908 558 305 1241 917 85 31 427 30 162 456 561 1431 889