Friction head

Friction head loss Friction match Friction materials... 

There are also many empirical formulas used for calculatiag the friction head loss in piping systems. These must be used carefuUy because many are based on the properties of specific fluids and are not appHcable over a broad range of fluids, temperatures, and pressures. For example, the Ha2en and Wdhams formula widely used for water flow ... 

Before installation it is possible to estimate the total discharge head from the static discharge nead and the discharge friction head hj as follows ... 

Friction Head This is the pressure required to overcome the resistance to flow in pipe and fittings. It is dealt with in detail in Sec. 5. 

For determining the frictional head, refer to friction loss in pipes, bends, elbows and reducers and valves as provided in Tables A.I and A.2 ... 

The term pump head represents the net work performed on the liquid by the pump. It is eomposed of four parts. They are the statie head (Hs), or elevation the pre.ssure head (Hp) or the pre.ssures to be overcome the friction head (Hf) and velocity head (Hf), which are frictions and other resistances in the piping system. These heads are discussed in Chapter 8. The head formula is the following ... 

Hf = Friction head or friction losses expressed in feet in the suction piping and connections. 

Hf Friction Head, or the frietion losses in the suetion piping. We eould a.ssign this a value of 1 ft. 

This could also be induced by design, if the pumps are oversized, or by high velocity and friction head in discharge piping of inferior diameter. 

Friction Head Loss (Resistance) in Pipe, Fittings, and Connections... 

Friction head loss develops as fluids flow through the various pipes, elbows, tees, vessel connections, valves, etc. These losses are expressed as loss of fluid static head in feet of fluid flowing. 

Alternate Calculation Basis for Piping System Friction Head Loss Liquids... 

The head losses calculated using K coefficients by these figures can be added directly to the total friction head loss for the straight pipe portions of a system. When equivalent lengths are determined, they must be added to the straight pipe before determining the total head loss, as shown in the example calculations for a water system. 

The total suction lift is defined as above except the level of the liquid is below the centerline of the pump or the head is below atmospheric pressure. Its sign is negative. Total Suction Lift (TSL) = static lift plus friction head losses. 

The dynamic factors of inertia and friction are related to the static factors. Velocity head and friction head are obtained at the expense of static head. However, a portion of the velocity head can always be reconverted to static head. Force, which can be produced by pressure or head when dealing with fluids, is necessary to start a body moving if it is at rest, and is present in some form when the motion of the body is arrested. Therefore, whenever a fluid is given velocity, some part of its original static head is used to impart this velocity, which then exists as velocity head. 

At all points in a system, the static pressure is always equal to the original static pressure less any velocity head at a specific point in the system and less the friction head required to reach that point. Since both the velocity head and friction head represent energy and energy cannot be destroyed, the sum of the static head, the velocity head, and the friction head at any point in the system must add up to the original static head. This is known as Bernoulli s principal, which states For the horizontal flow of fluids through a tube, the sum of the pressure and the kinetic energy per unit volume of the fluid is constant. This principle governs the relationship of the static and dynamic factors in hydraulic systems. 

Relative roughness, pipe, 132 Friction losses, 181 also see Chapter 2 Friction, head loss, 68 Compressible fluids, 101 Factor, 68 Vacuum lines, 131 Gas constants, R, 378 Gravity settlers, 228 Head, 180-200 Calculations, 183, 184, 185 Discharge, 180, 187 Friction, 183 Liquid, 183... 

Values of the holdup may be used to estimate the frictional losses in the pipe, since the overall difference in fluid head Ah of the liquid is equal to the friction head less the hold-up of liquid per unit area ... 

Let ccij and friction head loss per unit length of size j pipe in branch i. Then the actual hydraulic head at any node k must not be less than a specified minimum head h(k), that is... 

The suction head hs decreases and the discharge head hd increases with increasing liquid flow rate because of the increasing value of the friction head loss terms hfs and hfd. Thus the total head Ah which the pump is required to impart to the flowing liquid increases with the liquid pumping rate. 

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