factor, k, pressure, loss, flow, rate, local, head, hydraulic

http://www.thermexcel.com/english/ressourc/pdclocal.htm[4/13/2015 11:23:26 AM]

Local pressure loss calculation

The local pressure losses corresponding by the valves and fittings in the hydraulic networks are expressed by the following relation:

Dps = local pressure loss in Pap = density of the fluid in kg/m3V = rate of flow in m/sK = coefficient depend on the nature of local resistance

= Dynamic pressure of the fluid.

The local pressure losses are classified in 2 categories:

Those which are with constant value whatever the diameter of the network used, such as the changes of section (reductions, inlets and outlets of the pipes)

Those which vary according to the diameter of networks, whose pressure loss is due primarily by friction and turbulence occurring such as for example in a valve.

K-factor with constant value

It should be noted that the following values all are established according to the smallest diameter.

This value can be converted on the largest diameter by (dlarge/dlitle)4.

Changement de section K - Rduction concentrique - largissement d1/d2 = 0.90 0.026 - Rduction concentrique - largissement d1/d2 = 0.80 0.13 - Rduction concentrique - largissement d1/d2 = 0.75 0.16 - Rduction concentrique - largissement d1/d2 = 0.67 0.28 - Rduction concentrique - largissement d1/d2 = 0.50 0.5 - Rduction concentrique rtrcissement d1/d2 = 0.90 0.008 - Rduction concentrique - rtrcissement d1/d2 = 0.80 0.041 - Rduction concentrique - rtrcissement d1/d2 = 0.75 0.049 - Rduction concentrique - rtrcissement d1/d2 = 0.67 0.085 - Rduction concentrique - rtrcissement d1/d2 = 0.50 0.16Entre et sortie conduite - Entre conduite de niveau - r/d = 0.00 (angle vif) 0.5 - Entre conduite de niveau - r/d = 0.02 0.28 - Entre conduite de niveau - r/d = 0.04 0.24

Calculation of the singular pressure losses on hydraulic networks. Dynamic pressure, tables of the coefficients K (modules of pressure loss), evaluation of the singular pressure loss.

French site | Home | Thematic | Tables | Programs | Library | Download | Links | Contact | Forum |_You are in the heading Mon Apr 13 2015 11:22:38 GMT-0600 (Mountain Daylight Time)

-- Local pressure loss

ThematicQuotation

MarginHydraulic

Linear pressure loss

Local pressure loss

Compressible fluids

No circular ductThermal

Thermal fluid flow

Pipe sizing steam

Control valvesOrifice plate

PumpsVentilators

Gas

Fuel gas

factor, k, pressure, loss, flow, rate, local, head, hydraulic

http://www.thermexcel.com/english/ressourc/pdclocal.htm[4/13/2015 11:23:26 AM]

- Entre conduite de niveau - r/d = 0.06 0.15 - Entre conduite de niveau - r/d = 0.10 0.09 - Entre conduite de niveau - r/d > 0.15 (bien arrondie) 0.04 - Entre conduite saillante 0.78 - Sortie canalisation 1Divers Comptage (Consulter normalement le fabricant) - Compteur disque (K : 3,4 10) 10- Compteur rotatif 10- Compteur piston 15- Compteur turbine (K : 5 7.5) 7.5Branchement radiateurs y/c robinetterie - Piquage sur rseaux aller et retour, radiateur, robinetterie 15Ensemble chaudire y/c robinetterie - entre et sortie chaudire y/c changements brusques de sections, entre et sortie, vanne, tuyauterie de drivation, piquage, du vase d'expansion (8 12)

12

Tronon entre 2 piquages - sans variation de section 1.5- avec variation de section 3.5

K-factor depend on the diameter used

This calculation must be carried out separately for each pipe size, using the appropriate velocity within that pipe section.

Evaluation of local pressure loss

The singular pressure losses are expressed by:

Conversely, it is possible to know the value of K according to the pressure loss (read on an abacus)

V = Rate of flow in m/sDPs = Pressure loss in Pap = Density of the fluid in kg/m3 (depends on the temperature)K = coefficient depend on the nature of local resistance

Last update: 04/13/2015 11:22:38

Copyright 2003-2014 - ThermExcel - All Rights Reserved

thermexcel.comfactor, k, pressure, loss, flow, rate, local, head, hydraulic