Learning Goal: To calculate minor head losses and pressure drops for pipe fittings. Minor losses in pipe flow are the result of disruptions to the steady laminar or turblent flow in a pipe by entrances, bends, transitions, valves or other fittings. In general, calculating these losses analytically is too complex. However, all of these losses can be modeled V2 using terms of the form hL = KL 2g where KL is called the loss coefficient and is determined experimentally. This coefficient relates the minor head loss to the velocity head for the flow. For expansions and contractions, the loss coefficient is calculated using the velocity for the smaller diameter pipe. The table below gives some representative values for various minor head losses. These are representative only, and a more complete table would account for different kinds of fittings and connections (like threaded or soldered). Fitting Well-rounded entrance D > 0.15 A gate valve is being used as a shut-off valve in a pipe system. When the valve is fully open, the flow through the 8-cm diameter pipe is 50 L/min. What is the head loss a the gate valve? One liter is 0.001 cubic meters. Express your answer in m to three significant figures. View Available Hint(s) h = Submit vec Part B - Pressure drop m The flow of water in a pipe passes through sudden expansion from d = 5 cm to d = 7 cm. If the flow rate is Q = 0.03 m/s, what is the pressure drop due to expansion? The specific weight of water is yw = 9.802 kN/m Express your answer in kPa to three significant figures. KL 0.04 View Available Hint(s) Flush entrance 0.5 Re-entrant pipe 1.0 vec Discharge pipe 1.0 Sudden contraction (d to d) (Figure 1) Ap= ? kPa Sudden expansion (d, to d) (1-4) Submit Gate valve - fully open 0.19 Globe valve - fully open 10 Part C - Loss coefficient 90 elbow 0.90 45 bend 0.40 Tee along pipe run 0.40 Tee along branch 1.8 Figure 0.6 KL 0.4 0.2 0 0.2 0.4