Exercise Problems  -  Chapter 11

1. Calculate the force F required on the piston to discharge of water through a syringe (see Fig. 37.4), taking into account the frictional loss in the syringe needle only. Assume fully developed laminar flow in the syringe needle. Take the dynamic viscosity of water .

Figure 37.4

2. A hydrocarbon oil (viscosity 0.025 pa-s and density 900 kg/m³ ) is transported using a 0.6 m diameter, 10 km long pipe. The maximum allowable pressure drop across the pipe length is 1 MPa. Due to a maintenance schedule on this pipeline, it is required to use a 0.4 m diameter, 10 km long pipe to pump the oil at the same volumetric flow rate as in the earlier case. Estimate the pressure drop for the 0.4 m diameter pipe. Assume both pipes to be hydrodynamically smooth and in the range of operating conditions, the Fanning friction factor is given by:

3. Two reservoirs 1 and 2 are connected as shown in the Fig 37.5 through a turbine T. Given the friction factor relation

for the connecting pipes, the turbine characteristics of water [ Q in m³/s] and an ideal draft tube at the discharge end, find (a) the volume flow rate between the two reservoirs and (b) the power developed by the turbine. Note:

Use an initial guess for power developed by the turbine as 1 MW. Show only two iterations . Also H is head available at the turbine.

figure 37.5