The compressed air requirements of a textile factory are met by a large compressor that draws in 0.6 m³/s air at atmospheric conditions of 20°C and 1 bar (100 kPa) and consumes 300 kW electric power when operating. Air is compressed to a gage pressure of 8 bar (absolute pressure of 900 kPa), and compressed air is transported to the production area through a 30-cm-internal-diameter, 83- m-long, galvanized steel pipe with a surface roughness of 0.15 mm. The average temperature of compressed air in the pipe is 60°C. The compressed air line has 8 elbows with a loss coefficient of 0.6 each. If the compressor efficiency is 84 percent, determine the power wasted in the transportation line. The roughness of a galvanized steel pipe is given to be ε = 0.00015 m. The dynamic viscosity of air at 60°C is = 2.008 × 10-5 kg/m-s, and it is independent of pressure. The density of air listed in that table is for 1 atm. The density at 20°C, 100 kPa and 60°C, 900 kPa can be determined from the ideal gas relation to be Pin = Pin = P = Pline = 100 kPa (0.287 kPa-m³/kg-K) (20+273 K) Pline RTline = 1.189 kg/m³ 900 kPa (0.287 kPa-m³/kg-K) (60+273 K) The power wasted in the transportation line is 0.00483 = = = 9.417 kg/m³ kW.

A certain jet fuel has a kinematic viscosity of 1.2 x 10-6 m2/s. If the fuel is being delivered to the engine at 200 L/min through a steel tube (Diameter = 22.10 mm), compute the Reynold number and identify the type of flow either laminar or turbulent?

A constant-area duct that is 20 cm in length by 2 cm in diameter is connected to a reservoir through a converging nozzle, as shown in Figure 9.13. For a reservoir pressure and tem- perature of 1 MPa and 500 K, determine the maximum air flow rate in kilograms per sec- ond through the system and the range of back pressures over which this flow is realized. Repeat these calculations for a converging nozzle with no duct. Assume that fis equal to 0.032 and that y - 1.4. f= 0.032 D-2 cm Isentropic flow P1,000 kPa I 500 K 20 cm