Reference no: EM132280174
Questions -
Q1. An exhaust ventilation system is shown in Figure below. The head losses given are based on the assigned air quantities, and the shaft dimensions are 10 x 7.5 ft (3.05 x 2.29 m). Determine the quantity of air the fan must provide. Locate regulators where needed, specifying the amount of regulation at each. Find the mine heads and the air power.
Q2. In the exhaust ventilation system shown in the following figure, determine all of the missing quantities for individual segments of airway; locate regulators where needed and calculate the amount of regulation needed. Determine the static head for each of the two fans. Also, determine the size of the regulator to be placed across the heading containing Q12.
Q3. A temperature survey of a mine is made to investigate the natural ventilation. The data obtained are indicated in the figure below. The friction factor is 100 x 10-10 lb.min2/ft4 (0.01855 kg/m3), all airways are 10 x 10 ft (3.05 x 3.05 m), and the elevation of the collar of the higher shaft is 5000 ft (1524 m). Disregarding the shock losses and the velocity head, compute the natural ventilation head, and the quantity of flow and air power on the basis of the most reliable calculated head. Indicate the direction of flow and sketch the characteristic curve of the system.
Q4. The following data are obtained during a test of a vane-axial mine fan:
Static Head in. (kPa)
|
Quantity cfm ( m3/s)
|
Power Input Bhp (kW)
|
8.00 (1.99)
|
0 (0)
|
37.6 (28.0)
|
7.65 (1.90)
|
5,000 (2.36)
|
35.5 (26.5)
|
6.00 (1.49)
|
12,500 (5.90)
|
24.0 (17.9)
|
6.65 (1.65)
|
16,000 (7.55)
|
25.5 (19.0)
|
6.10 (1.52)
|
20,000 (9.44)
|
25.0 (18.6)
|
3.70 (0.92)
|
25,000 (11.80)
|
21.0 (15.7)
|
0 (0)
|
28,600 (13.50)
|
13.0 (9.7)
|
The fan has a diameter of 38 in. (965 mm) and a speed of 1750 rpm, and the air specific weight is 0.075 lb/ft3 (1.20 kg/m3). Plot characteristic curves of the fan for quantity versus static and total heads, power input, static and total air power, and static and total efficiency. Tabulate all data used in plotting curves.