A. Loss coefficient

A system loss coefficient is defined as the difference of the nondimensionalized total pressure loss between the extreme ends of two long straight pipes or passages when there is a zero loss component between the two pipes or passages and when the real component is installed; see Miller (1990). In nondimensionalizing the pressure loss, the convention is to use the component's inlet dynamic pressure, except when the component is an inlet from a large space the outlet dynamic pressure is used. The long pipe before the component ensures a developed flow at inlet and the long pipe at outlet from the component ensures that losses caused by flow redevelopment after the component are debited to the component. Figure 1 illustrates the procedure for establishing the loss coefficient. The inlet and outlet developed friction gradients are projected to the component and the difference between the projected total pressures at the component is established.

Figure 1 Definition of loss coefficient. K according to Equation 1

The loss coefficient K is given by

\[\label{eq1}K=\frac{\Delta p_t}{(\rho/2)\overline{u}^2}\tag{1}\]