Pablo
Borbon
Campus
Alangilan
Campus
College of Engineering – Department of Electronics Engineering
BACHELOR OF SCIENCE IN AEROSPACE ENGINEERING
LONG QUIZ
SET A
PROBLEM SOLVING:
1.
Consider an airplane flying at some real altitude. The outside pressure
and temperature are 2.65 x 10' N/m2 and 220 K, respectively. What are
the pressure and density altitudes?
Pressure altitude: 10km
2.
Consider an airplane flying at an altitude where the pressure and
temperature are 530 lb/ft2 and 390°R, respectively. Calculate the
pressure and density altitudes at which the airplane is flying.
Alangilan, Batangas City, Philippines
+63 43 425 - 0139 loc. 2121
www.batstate-u.edu.ph
coe.alangilan@g.batstate-u.edu.ph
Pablo
Borbon
Campus
Alangilan
Campus
College of Engineering – Department of Electronics Engineering
BACHELOR OF SCIENCE IN AEROSPACE ENGINEERING
3.
Consider the incompressible flow of water through a divergent duct. The
inlet velocity and area are 5 ft/s and 10 ft2, respectively. If the exit area
is 4 times the inlet area, calculate the water flow velocity at the exit.
4.
An instrument used to measure the airspeed on many early low-speed
airplanes, principally during 1919 to 1930, was the venturi tube. This
simple device is a convergent-divergent duct. (The front section's crosssectional area A decreases in the flow direction, and the back section's
cross-sectional area increases in the flow direction. Somewhere between
the inlet and exit of the duct, there is a minimum area called the throat.)
See figure below. Let A1 and A2 denote the inlet and throat areas,
respectively. Let P1 and P2 be the pressures at the inlet and throat,
respectively. The venturi tube is mounted at a specific location on the
airplane (generally on the wing or near the front of the fuselage) where
the inlet velocity V1 is essentially the same as the free-stream velocitythat is, the velocity of the airplane through the air. With a knowledge of
the area ratio A2/A1 (a fixed design feature) and a measurement of the
pressure difference P1 - P2, we can determine the airplane's velocity. For
example, assume A2/A1 = ¼ and P1 - P2= 80 lb/ft2. If the airplane is flying
at standard sea level, what is its velocity?
Alangilan, Batangas City, Philippines
+63 43 425 - 0139 loc. 2121
www.batstate-u.edu.ph
coe.alangilan@g.batstate-u.edu.ph
Pablo
Borbon
Campus
Alangilan
Campus
College of Engineering – Department of Electronics Engineering
BACHELOR OF SCIENCE IN AEROSPACE ENGINEERING
Alangilan, Batangas City, Philippines
+63 43 425 - 0139 loc. 2121
www.batstate-u.edu.ph
coe.alangilan@g.batstate-u.edu.ph
Pablo
Borbon
Campus
Alangilan
Campus
College of Engineering – Department of Electronics Engineering
BACHELOR OF SCIENCE IN AEROSPACE ENGINEERING
5. Derive an expression for the exit velocity of a supersonic nozzle in terms
of the pressure ratio between the reservoir and exit P0/Pe and the reservoir
temperature T0.
Alangilan, Batangas City, Philippines
+63 43 425 - 0139 loc. 2121
www.batstate-u.edu.ph
coe.alangilan@g.batstate-u.edu.ph
Pablo
Borbon
Campus
Alangilan
Campus
College of Engineering – Department of Electronics Engineering
BACHELOR OF SCIENCE IN AEROSPACE ENGINEERING
LONG QUIZ
SET B
PROBLEM SOLVING:
1.
Consider an airplane flying at an altitude where the pressure and
temperature are 530 lb/ft2 and 390°R, respectively. Calculate the
pressure and density altitudes at which the airplane is flying.
2.
Consider an airplane flying at some real altitude. The outside pressure
and temperature are 2.65 x 10' N/m2 and 220 K, respectively. What are
the pressure and density altitudes?
3.
Consider the incompressible flow of water through a divergent duct. The
inlet velocity and area are 5 ft/s and 10 ft2, respectively. If the exit area
is 4 times the inlet area, calculate the water flow velocity at the exit.
4.
Derive an expression for the exit velocity of a supersonic nozzle in terms
of the pressure ratio between the reservoir and exit P0/Pe and the reservoir
temperature T0.
5.
An instrument used to measure the airspeed on many early low-speed
airplanes, principally during 1919 to 1930, was the venturi tube. This
simple device is a convergent-divergent duct. (The front section's crosssectional area A decreases in the flow direction, and the back section's
cross-sectional area increases in the flow direction. Somewhere between
the inlet and exit of the duct, there is a minimum area called the throat.)
See figure below. Let A1 and A2 denote the inlet and throat areas,
respectively. Let P1 and P2 be the pressures at the inlet and throat,
respectively. The venturi tube is mounted at a specific location on the
airplane (generally on the wing or near the front of the fuselage) where
the inlet velocity V1 is essentially the same as the free-stream velocitythat is, the velocity of the airplane through the air. With a knowledge of
the area ratio A2/A1 (a fixed design feature) and a measurement of the
pressure difference P1 - P2, we can determine the airplane's velocity. For
example, assume A2/A1 = ¼ and P1 - P2= 80 lb/ft2. If the airplane is flying
at standard sea level, what is its velocity?
Alangilan, Batangas City, Philippines
+63 43 425 - 0139 loc. 2121
www.batstate-u.edu.ph
coe.alangilan@g.batstate-u.edu.ph
Pablo
Borbon
Campus
Alangilan
Campus
College of Engineering – Department of Electronics Engineering
BACHELOR OF SCIENCE IN AEROSPACE ENGINEERING
Imagine that you have designed a low-speed airplane with a maximum velocity
at sea level of 90 m/s. For your airspeed instrument, you plan to use a venturi
tube with a 1.3: 1 area ratio. Inside the cockpit is an airspeed indicator-a dial
that is connected to a pressure gauge sensing the venturi tube pressure
difference p1 - P2 and properly calibrated in terms of velocity. What is the
maximum pressure difference you would expect the gauge to experience?
The mass flow of air through a supersonic nozzle is 1.5 lb/s. The exit velocity
is 1500 ft/s, and the reservoir temperature and pressure are 1000°R and 7 atm,
respectively. Calculate the area of the nozzle exit. For air, Cp = 6000 ft.lb/
(slug)(°R).
Alangilan, Batangas City, Philippines
+63 43 425 - 0139 loc. 2121
www.batstate-u.edu.ph
coe.alangilan@g.batstate-u.edu.ph