Friction losses in pipes pdf

Friction Losses of Head in Pipes : There are many types of losses of head for flowing liquids such as friction , inlet and outlet losses. The major loss is that due to frictional resistance of the pipe , which depends on the inside roughness of the pipe. The common formula for calculating the loss of head due to friction is Darcy’s one. Most pipe systems consist of considerably more than straight pipes.

These additional components add to the overall head loss of the system.

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 example, it may be desired to predict the rate of flow along a proposed pipe connecting two reservoirs at different levels. Example: Determine L ( friction loss in pipe fittings in terms of equivalent length in feet of straight pipe ). Assume a angle valve for Schedule pipe size. Select the appropriate K value for such and select D and f for Schedule pipe from the table below where K is the pipe diameter in feet.

INTRODUCTION The flow of fluid in a pipe is accompanied by the loss of energies as a result of the interaction between the fluid and the viscous stresses on the wall of the pipe. The energy loss may be in the form of pressure loss in the system due to friction , pipe bend or connections etc.

Let L = length of the pipe between sections and 2. Year Old Pipe - The friction values for Old Pipe are based on Williams and Hazen coeffi cient of C=100. Energy losses in pipes used for the transportation of fluids (water, petroleum, gas, etc.) are essentially due to friction , as well as to the diverse singularities encountered. PSI loss due to friction losses in the pipe hf fittings = the PSI loss due to friction losses in fittings hf valves = the PSI loss due to friction losses in valves, meters or other appurtenances between the source and the given point in the system ELEVATION VIEW Water Meter ↓ Point A ↑ Point B Control Valve 1ft. Flow in pipes In this chapter, however, a method of expressing the loss using an average flow velocity is stated. Studies will be made on how to express losses caused by a change in the cross sectional area of a pipe , a pipe bend and a valve, in addition to the frictional loss of a pipe.

As fluid travels through sections of pipes or ducts or experiences a change in velocity in a fitting, energy is dissipated as heat and is lost. Energy lost due to friction in pipes is commonly termed “major losses” and occurs due to the frictional characteristics of the pipe or duct material acting on the flowing fluid. Energy loss through friction in the length of pipeline is commonly termed the major loss (h f) which is the loss of head due to pipe friction and to viscous dissipation in flowing water. Independent variables: Gallons per minute and nominal pipe size O. Dependent variables: Velocity, friction head and pressure drop per 1feet of pipe , interior smooth. Friction Loss lbs per Square Inch Friction Head Feet V elocity Feet per Second Friction Loss lbs per Square Inch Friction Head Feet V elocity Feet per Second Friction Loss lbs.

These losses are usually converted into head reductions in the direction of the flow. In the region near the entrance, the flow in the center of the pipe is unaffected by the friction between the pipe wall and the fluid. At the end of the entrance region, the pattern of velocity across the pipe (the velocity profile) has reached its final shape.

In a ben in addition to the head loss due to pipe friction , a loss due to the change in flow direction is also produced. Here, k is the loss factor due to the bend effect. Based on the value of Friction factor, the condition of pipes after they were operated for two years is relatively goo.

Friction Loss in Fittings Valves As an ai liquid sizing constants (Cv values) are shown for valves. These values are defined as the flow rate through the valve required to produce a pressure drop of psi. To determine the pres-sure drop for a given GPM the following formula may be used. Minor in comparison to friction losses which are considered major. Losses are proportional to – velocity of flow, geometry of device.

You will also explore effects of the skin friction , pipe network configuration, and pipe fittings (tees, elbows, etc.) on the pressure drop across a pipe. Major” losses occur due to friction within a pipe , and “minor” losses occur at a change of section, valve, bend or other interruption. In this practical you will investigate the impact of major and minor losses on water flow in pipes. This is different from major losses because those come from friction in pipes over long spans.

Minor losses in pipes come from changes and components in a pipe system. If the pipe is long enough the minor losses can usually be neglected as they are much smaller than the major losses.