At Tw= 100oC uniform temperature, L= 26m long, D=2.3cm diameter pipe passes motor oil at =3 kg/s flow rate and Ti = 40oC temperature. The flow is hydrodynamically developed and the average Nusselt number is Num=7.5. Accordingly; Find a) the average heat transfer coefficient, b) the outlet temperature of the engine oil, c) the total amount of heat transfer transferred to the oil, and d) the thermal inlet length. (Variables: L= 20-40m, =2-4 kg/s, D=1.5-3 cm)

Air at 1 atm and 20 C flows through a smooth pipe. The centerline velocity and the pipe diameter are 6 m/s and 15 cm, respectively. Find a) the wall shear stress and b) the average velocity in the pipe.

The figure shown below is a series pipeline system used to draw a fluid from a lower source open tank to a higher destination open tank . The flow and geometric layout for the system are listed below: Fluid: water       Volume flow rate: Q=0.015 m3/s Elevation difference:  h=8.0m of two free surfaces Suction line:                      DN100 Sch. 40 Steel pipe                      Length: Ls=2.0 m                      Valve1: hinged disc type foot valve                      Entrance type: well-rounded Discharge line:                           DN80 Sch. 40 Steel pipe                           Length: Ld=100 m                           Valve2: full open gate valve                           Elbows:  90ο long radius elbow   (1)  Select the simplified general energy equations for section 1 and 2_________       A.     B.     C.     D.

A pump delivers water between a reservoir and a water tank. The surface waterelevation of the water tank is 20m higher. The suction side contains an entrance strainer (Ks=2.5), and50m of PVC pipe that is 25cm in diameter. The discharge side includes a 200m long PVC pipe, 25 cmin diameter, and a gate valve. The net positive suction head (NPSH) is 7.5m, and the design discharge is150L/s. Determine the allowable elevation difference between the pump and the reservoir water surface,z s, to avoid cavitation. Assume a kinematic viscosity of 1x10-6m 2 /s and a specific weight of 9.79kN/m 3 .