Lecture 21: Minor loss, kinetic energy correction factor
Energy balance equation: Minor losses
The energy balance equation contains a term, ‘’ which represents irreversible conversion of viscous work to thermal energy and is always ‘+ ve’:
(neglecting any shaft work) (Note: it has been shown that
Minor losses refer to the losses in pipe bends, fittings, valves, and nozzles, etc, whereas major losses refer to the same in a long pipe or tube. We will first minor losses. Example1 Consider the following system of pipe flow, consisting of several fittings such as pipe bends, and valves:
(Fig. 21a)
As the fluid flows through pipe and associated fittings, including valves, there is invariably loss of mechanical energy, which may be mathematically quantified as: , where, is often calculated at the inlet to the fitting or valves and K is known as loss coefficient and depends on Reynolds number and type of fittings. The manufacturers of valves and fittings provide ‘K’ value. For example:
’ which represents irreversible conversion of viscous work to thermal energy and is always ‘+ ve’:
, where, 
is often calculated at the inlet to the fitting or valves and K is known as loss coefficient and depends on Reynolds number and type of fittings. The manufacturers of valves and fittings provide ‘K’ value. For example:
