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2. Fanno flow - Wikipedia

   en.wikipedia.org/wiki/Fanno_flow

   The viscous friction causes the flow properties to change along the duct. The frictional effect is modeled as a shear stress at the wall acting on the fluid with uniform properties over any cross section of the duct. For a flow with an upstream Mach number greater than 1.0 in a sufficiently long duct, deceleration occurs and the flow can become ...

3. Moody chart - Wikipedia

   en.wikipedia.org/wiki/Moody_chart

   where is the density of the fluid, is the average velocity in the pipe, is the friction factor from the Moody chart, is the length of the pipe and is the pipe diameter. The chart plots Darcy–Weisbach friction factor f D {\displaystyle f_{D}} against Reynolds number Re for a variety of relative roughnesses, the ratio of the mean height of ...

4. Duct (flow) - Wikipedia

   en.wikipedia.org/wiki/Duct_(flow)

   Round duct is made using a continuous spiral forming machine which can make round duct in nearly any diameter when using the right forming die and to any length to suit, but the most common stock sizes range evenly from 4" to 24" (10-60 cm) with 6"-12" (15-30 cm) being most commonly used. Stock pipe is usually sold in 10' (300 cm) joints.

5. Friction loss - Wikipedia

   en.wikipedia.org/wiki/Friction_loss

   The following table gives flow rate Q such that friction loss per unit length Δp / L (SI kg / m 2 / s 2) is 0.082, 0.245, and 0.816, respectively, for a variety of nominal duct sizes. The three values chosen for friction loss correspond to, in US units inch water column per 100 feet, 0.01, .03, and 0.1.

6. Darcy–Weisbach equation - Wikipedia

   en.wikipedia.org/wiki/Darcy–Weisbach_equation

   Most charts or tables indicate the type of friction factor, or at least provide the formula for the friction factor with laminar flow. If the formula for laminar flow is f = ⁠ 16 / Re ⁠, it is the Fanning factor f, and if the formula for laminar flow is f D = ⁠ 64 / Re ⁠, it is the Darcy–Weisbach factor f D.

7. Hazen–Williams equation - Wikipedia

   en.wikipedia.org/wiki/Hazen–Williams_equation

   P d = pressure drop over the length of pipe in psig (pounds per square inch gauge pressure) L = length of pipe in feet; Q = flow, gpm (gallons per minute) C = pipe roughness coefficient; d = inside pipe diameter, in (inches) Note: Caution with U S Customary Units is advised. The equation for head loss in pipes, also referred to as slope, S ...

8. Darcy friction factor formulae - Wikipedia

   en.wikipedia.org/wiki/Darcy_friction_factor_formulae

   Before choosing a formula it is worth knowing that in the paper on the Moody chart, Moody stated the accuracy is about ±5% for smooth pipes and ±10% for rough pipes. If more than one formula is applicable in the flow regime under consideration, the choice of formula may be influenced by one or more of the following: Required accuracy

9. Ductwork airtightness - Wikipedia

   en.wikipedia.org/wiki/Ductwork_airtightness

   There are two major systems to classify ductwork airtightness, one based on European standards, the other based on ASHRAE standard 90.1-2010.Both are based on the leakage airflow rate at a given ductwork pressure divided by the product of the ductwork surface area and the same ductwork pressure raised to the power 0.65.