Tables and formulas needed to perform the head loss calculations.
The Darcy friction factor takes the fluid properties of density and viscosity into account, along with the pipe roughness. Although these factors seem to most people to have an effect on head loss, the Darcy equation does not account for them. In this case, little information about the properties of the process fluid or the surface roughness on the inside of the pipe material is available. With the exception of the Darcy friction factor, each of these terms can be easily measured. If the flow rate is doubled, the head loss increases by a factor of four. If the inside pipe diameter is doubled, the head loss will be reduced by half. If the length of the pipe is doubled, the head loss will double. Q = Volumetric flow rate (gallons/minute)Įvaluating the Darcy equation provides insight into factors affecting the head loss in a pipeline. G = Gravitational constant (32.2 feet/sec 2) The head loss in a pipeline with Newtonian fluids can be determined using the Darcy equation (Equation 1). This conversion and loss of energy is known as head loss. This thermal energy cannot be converted back to hydraulic energy, so the fluid experiences a drop in pressure. This friction converts some of the fluid’s hydraulic energy to thermal energy.
When fluid flows inside a pipeline, friction occurs between the moving fluid and the stationary pipe wall. For simplification this discussion will be limited to the flow of Newtonian fluids through circular pipelines. Water, oils, solvents and petroleum products are examples of Newtonian fluids. Most fluids used in industrial applications are Newtonian, meaning that their viscosity does not change with the rate of flow. Each of these items affects the head loss in the pipeline.
#PREFERRED SCALE FACTOR FIRE SPRINKLER DESIGN FULL#
A pipeline consists of a circular pipe full of fluid, the process fluid, and the valves and fittings used to direct the flow of fluid through the pipe in the operation. This column will explore pipelines in detail, consider how they affect the operation of piping systems, and review the method for calculating head loss in pipelines.Ī pipeline is a circular conduit used to convey process fluid from one location in the system to another. Last month’s column explored the effects that oversizing a pump has on the motor driving the pump, the adverse results of a pump no longer operating at its best efficiency point (BEP) for extended periods of time and situations in which a design margin could increase cost of ownership.
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