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Question 1 Part A: 8 marks A mixture of water and acetic acid (which has a combined density 1050 kg/m & a dynamic viscosity of 0.00108 N.s/m2) is circulated through a pipe network (100mm diameter with a surface roughness of 0.03mm) at a flow rate of 30 kg/s. Calculate i) the volumetric flow rate, and velocity [3] ii) the Reynolds number and hence the friction factor. [5] Part B: 10 marks The pipe network runs between two tanks (k for pipe entry of 0.2 and exit 1) over a distance of 25 m, with a total static lift of 10 m between the two tanks. This pipe network includes two long sweeping elbows, a Mitre bend and a gate valve ('74 open). Calculate: iii) the total head loss [7] iv) the hydraulic output required to pump the mixture between the two tanks [3] Part C: 12 marks The valve position in part B is changed, reducing the mass flow rate to 25 kg/s and the power output changes to 3.7 kW's. Determine, the new operating conditions (velocity, friction factor, hydraulic head, etc.). Then determine, to the nearest quarter, the new valve position of the gate valve. The following equations are given, as well as table 1:1 for the equivalent lengths of pipe and a moody diagram overleaf with the friction factor equation. Thus head loss for turbulent flow is: Exit/Entry losses are: Δh = hexit 2gD 2g Reynold's number: Hydraulic output: pod Powerout = pg(Eh) д foLU2 ky 2 Re = 4.7 m Table 1:1 Equivalent lengths of pipe for selected fittings 100mm diameter Gate valv fully open 0.8 m Gate valve 1/4 closed Gate valvehalf closed 22 m Gate valve 3/4 closed 92 m T-piece-flow through run 2.1 m T-piece-flow through branch 8.5 m long sweeping elbow 2.1 m Mitre bend 5.2 m Total marks [30] 2