physical物理代考-HYDRAULICS代写-留学作业代写

TCE2134 – HYDRAULICS

(Semester 2 : AY 2017/2018)

Time Allowed: 2.5 Hours

physical物理代考 A mercury manometer (ρm=13.6ρ) is connected to the pipe as shown and gives a reading of hm=6.1cm. Water density is ρ=1000kg/m3.

INSTRUCTIONS TO STUDENTS

1.Please write your Student Number only. Do not write your name.

2.This assessment paper contains FOUR (4) questions and comprisesSIX (6) printed pages.

3.Students are required to answer ALL questions.

4.Students are to write the answers for each question on a new page.

5.This is an OPEN BOOK assessment.

6.Linear graph paper is provided.

7.Only non-programmable calculators are allowed.

Question 1 physical物理代考

The sketch shows a section of a pipe in which a nozzle-sleeve is inserted in the pipe. The pipe has a square cross-section with a side length of ap=10 cm, and the nozzle-sleeve reduces this side length to aN=ap/2=5 cm. A mercury manometer (ρm=13.6ρ) is connected to the pipe as shown and gives a reading of hm=6.1cm. Water density is ρ=1000kg/m³.

(a)Determine the discharge Q inthe (9 marks)

(b)Determine the head loss associated with the nozzle-sleeve when wall friction is neglected.(5 marks)

(c)Determine the force exerted by the flow on the nozzle-sleeve when wall friction is also neglected.(11 marks)

Question 2 physical物理代考

The figure below depicts two pipes connecting to reservoirs at different elevations. The pipes have a roughness of ε = 0.046 mm. The loss coefficient for the valve is 3.5, which is referred to the average velocity in the bigger pipe. The inlet of the pipe has a contraction coefficient Cv=0.5. A steady discharge of 0.12 m3/s is produced in the pipes.

(a)What is the total frictionalhead loss? (12 marks)

(b)What is the head difference, H, between thetwo tanks? (13 marks)

Question 3 physical物理代考

A large rectangular billboard has a length of 5 m and a height of 1 m and negligible thickness.The approaching wind of m/s is assumed uniform with the height. The wind is blowing along the length of the billboard and has a velocity profile given by

when it leaves the billboard as shown in Fig. Q3.1. is the boundary layer thickness at the trailing end of the billboard with the limiting streamline as shown.

(a)What is the total drag force onthe billboard? (5 marks)

(b)From the conservation of mass flow through the control volume shown in Fig. Q3.1, show thatthe region where the wind starts to feel the presence of the billboard is given by. (4 marks)

(c)From the momentum equation, determine the thickness of the boundary layer at the trailing edge of the billboard.(6 marks)

(d)How would you find the rate of loss of kinetic energy of the wind as it flows past the billboard? Where does the energy go if the billboard is rigid? State your assumptions clearly.(5 marks)

There is a change in the wind direction. The same wind is now blowing directly against the billboard, that is, the wind direction is perpendicular to the plane of the billboard.

(e)Whatis the total drag force on the billboard? State your assumptions clearly.(5 marks)

Fig. Q3.1

Question 4 physical物理代考

A centrifugal pump is used to deliver water to two reservoirs via a pipeline system shown in Fig. Q4.1. Water levels at reservoirs #2 and #3 are at elevations 35 m and 15 m above the sump level of the pump respectively. Assume that the sump level is maintained at a constant level. Thefrictional head loss is based on . With the gate valve at the delivery pipe fully open, neglect losses other than friction. The performance curves of the selected pump with the impeller diameter of 259 mm are shown in Fig. Q4.2.

(a)What is the expected optimum operating point of thepump?(2 marks)

(b)Determine the flows into the reservoirs #2 and #3 when the pump has to deliver at least the flow corresponding to maximum efficiency.(10 marks)

(c)Does the elevation of the junction J affect the division of flows to the reservoirs? Explain your answer.(3 marks)

(d)If the pump is set above the sump, what is the maximum height above the sump water level to which its centerline can beset?(5 marks)

(e)If the pump with the impeller diameter of 230 mm has been selected instead of the larger one, find the speed at which the pump is required to run to achieve the optimum operating discharge in (a). What will be the head at this newspeed?(5 marks)