Air flows though the mitered bend shown in Fig. P8.57 at arate of 5.0 cfs. To help

Air at standard temperature and pressure flows through a 1-in.-diameter galvanized iron pipe with an average velocity of 8 ft/s. What length of pipe produces a head loss equivalent to (a) a flanged 90 elbow, (b) a wide-open angle valve, or (c) a sharp-edged entrance?

Given 90 threaded elbows used in conjunction with copper pipe (drawn tubing) of 0.75-in. diameter, convert the loss for a single elbow to equivalent length of copper pipe for wholly turbulent flow.

To conserve water and energy, a flow reducer is installed in the shower head as shown in Fig. P8.52. If the pressure at point (1) remains constant and all losses except for that in the flow reducer are neglected, determine the value of the loss coefficient (based on the velocity in the pipe) of the flow reducer if its presence is to reduce the flowrate by a factor of 2. Neglect gravity.

Water flows at a rate of 0.040 m3 /s in a 0.12-m-diameter pipe that contains a sudden contraction to a 0.06-m-diameter pipe. Determine the pressure drop across the contraction section. How much of this pressure difference is due to losses and how much is due to kinetic energy changes?

Water flows from the container shown in Fig. P8.54. Determine the loss coefficient needed in the valve if the water is to bubble up 3 in. above the outlet pipe. The entrance is slightly rounded.

(See The Wide World of Fluids article titled New Hi-tech Fountains, Section 8.5.) The fountain shown in Fig. P8.55 is designed to provide a stream of water that rises h = 10 ft to h = 20 ft above the nozzle exit in a periodic fashion. To do this the water from the pool enters a pump, passes through a pressure regulator that maintains a constant pressure ahead of the flow control valve. The valve is electronically adjusted to provide the desired water height. With h = 10 ft the loss coefficient for the valve is KL = 50. Determine the valve loss coefficient needed for h = 20 ft. All losses except for the flow control valve are negligible. The area of the pipe is 5 times the area of the exit nozzle.

Water flows through the screen in the pipe shown in Fig. P8.56 as indicated. Determine the loss coefficient for the screen.

Air flows though the mitered bend shown in Fig. P8.57 at a rate of 5.0 cfs. To help straighten the flow after the bend, a set of 0.25-in.-diameter drinking straws is placed in the pipe as shown. Estimate the extra pressure drop between points (1) and (2) caused by these straws.

As shown in Fig. P8.58, water flows from one tank to another through a short pipe whose length is n times the pipe diameter. Head losses occur in the pipe and at the entrance and exit. (See Video V8.10.) Determine the maximum value of n if the major loss is to be no more than 10% of the minor loss and the friction factor is 0.02.

Water flows steadily through the 0.75-in.-diameter galvanized iron pipe system shown in Video V8.16 and Fig. P8.59 at a rate of 0.020 cfs. Your boss suggests that friction losses in the straight pipe sections are negligible compared to losses in the threaded elbows and fittings of the system. Do you agree or disagree with your boss? Support your answer with appropriate calculations.