EAS109e Copyright © 2016 SIM University Page 2 of 5 Examination – July Semester 2016

Answer all questions. (Total 100 marks) Question 1 The siphon ASB of constant diameter shown in Figure Q1 delivers water from a tank to a free discharge, B 1.5 m below the water level at A. The height, S is 0.5 m above the water level A. (Take atmospheric pressure as 1.01 bar and density of water as 1000 kgm-3.)

Figure Q1

(a) Apply an appropriate method to find the velocity, at S, in ms-1 to 2 decimal places,

when the siphon starts operation. (15 marks)

(b) Neglecting losses, evaluate the absolute pressure at S, in kPa. State all

assumptions. (5 marks)

(c) There is a hole in the pipe at T. Conduct an investigation and explain whether air

will enter or water will leak out of the pipe. (5 marks)

Answer all questions. (Total 100 marks) Question 1 The siphon ASB of constant diameter shown in Figure Q1 delivers water from a tank to a free discharge, B 1.5 m below the water level at A. The height, S is 0.5 m above the water level A. (Take atmospheric pressure as 1.01 bar and density of water as 1000 kgm-3.)

Figure Q1

(a) Apply an appropriate method to find the velocity, at S, in ms-1 to 2 decimal places,

when the siphon starts operation. (15 marks)

(b) Neglecting losses, evaluate the absolute pressure at S, in kPa. State all

assumptions. (5 marks)

(c) There is a hole in the pipe at T. Conduct an investigation and explain whether air

will enter or water will leak out of the pipe. (5 marks)

EAS109e Copyright © 2016 SIM University Page 3 of 5 Examination – July Semester 2016

Question 2 Figure Q2 shows a jet engine fixed onto a static thrust test bench.

Figure Q2

The details of the test set-up are listed as follows:

Inlet air pressure = -22 kPa (gauge) Exhaust air/fuel pressure and ambient pressure = 101 kPa (atmospheric

pressure) Engine intake area, A1 = 1 m2; Engine exhaust area to be calculated in

Q2(b) Intake air velocity = 200 ms-1; Exhaust air/fuel velocity = 400 ms-1 [The atmospheric pressure is 101 kPa while the local temperature = 30 0C. For air you may take R, the specific gas constant for air as 287 Jkg-1K-1]

(a) Duplicate Figure Q2 in your answer book and add the following:

(i) The control volume (CV) which will frame your calculations; (ii) the axes that will define the direction for the momentum force calculation; (iii) all horizontal external forces acting on the control volume; (iv) the mass flow rates into and leaving the CV.

Question 2 Figure Q2 shows a jet engine fixed onto a static thrust test bench.

Figure Q2

The details of the test set-up are listed as follows:

Inlet air pressure = -22 kPa (gauge) Exhaust air/fuel pressure and ambient pressure = 101 kPa (atmospheric

pressure) Engine intake area, A1 = 1 m2; Engine exhaust area to be calculated in

Q2(b) Intake air velocity = 200 ms-1; Exhaust air/fuel velocity = 400 ms-1 [The atmospheric pressure is 101 kPa while the local temperature = 30 0C. For air you may take R, the specific gas constant for air as 287 Jkg-1K-1]

(a) Duplicate Figure Q2 in your answer book and add the following:

(i) The control volume (CV) which will frame your calculations; (ii) the axes that will define the direction for the momentum force calculation; (iii) all horizontal external forces acting on the control volume; (iv) the mass flow rates into and leaving the CV.

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