 DH is the pressure drop of major head loss in meter column fluid
 l is the major head loss coefficient
 V is the average flow velocity
 g is graity (9.81)

Minor head loss (or elements pressure drop) of aeraulic and hydraulic networks are pressure losses caused by the passage of fluid through obstacles and accessories such as valves, fittings, expansion, exit tank, extractor hood etc ... .

the Minor head loss are expressed in Pascals, in meters fluid columns (m), or in equivalent meters of straight pipe.. the Minor head loss are also named elements pressure drop. These are the pressure losses due to elements encountered in the fluid path.

Minor head loss coefficients are given for the usuals elements of fluid's networks. In general, these data are provided by the manufacturers of hydraulic accessories. Some formulas used to calculate these coefficients, as Weisbach formula for elbows or Lorenz for divergent cones.
 Editor minor head loss elements
 table coefficients
 Internal flow exemple
 Valve pressure drop
 Formula pressure drop head loss
With MECAFLUX:
Curves of losses of one hundred basic accessories are available and configurable il Mecaflux standard software. (Example closing angle of hydraulic valve, the number of guide vanes in an elbow aeraulic ...)
The minor head loss coefficient is automatically based on parameters you enter..The minor head loss coefficient selected in the graph and the computed pressure drop caused by aeraulic or hydraulic accessories that you have chosen, is given to you in the results sheet.
The chart interface selection and parametrage elments pressure loss (minor head loss) in MECAFLUX:
here a gate valve
a grid composed of profile bars
a perforated plate filter
calculation procedure with mecaflux:
 select an aeraulicor hydraulic accessories, choosing a "category" and "element" (nomogram of a hundred different accessories)
 fill in the fields with blue text under "parameters"
 cliquez sur calculer
ou can add elements to the list of minor pressure losses elements.To do this a nomogram element editor is available.
the losses in the heat exchangers is treated in regular elements:
Here are some examples of items already included in mecaflux (not complete list ... mecaflux integrates the charts of one hundred basic accessories Ventilation and hydraulic configurable)Exemples of charts for minor head loss coefficients of some usual éléments in a fluid network
example coefficient minorhead loss, in equivalent length of straight duct