MOCK PPLANT 2 - 1 AERO

Which of the following is an extensive property of a system?

Volume

Blowing balloons are a great example of

Avogadro's Law

An approximately spherical balloon has a maximum diameter of 5 meters. At an initial pressure of 400 psi at 40 Celcius, the diameter is at 4 meters. If we keep the temperature constant, what should the pressure be at the maximum diameter?

204.8 psi

At 11 km, the temperature remains constant at 216.66 K and pressure at 22606 Pa, What is the density?

0.364 kg/m^3

A Carnot engine operates between 527°C and 27°C. What is the thermal efficiency?

0.6

In a reciprocating engine, at the end of the intake stroke, it has a pressure, Temprature, and a volume of 95 kPa, 26 C. and 5600 cm^3 respectively. Has a compression ratio of 9, and 8.9 KJ was added during the ignition stroke. What will be its efficiency thermally?

0.585

A diesel engine at the end of the intake stroke has a pressure and temperature of 95 kpa and 27 C respectively. Has a cut off ratio and compression ratio of 2 and 16 respectively. What is the engines thermal efficiency?

0.614

During the start of the isentropic air compression, it has a temperature and pressure of 27 C and 0.1 MPA respectively. At the end of the combustion process, it has a temperature of 800 C. SInce it has a pressure ratio of 6.25. What will be its thermal efficiency?

0.407

A gas turbine operates on an ideal Brayton cycle with a pressure ratio of 4. Assume k=1.4. What is the thermal efficiency of the cycle?

0.33

Keeps gas out of the crankshaft

Piston Ring

This bearing is used for camshafts, crankshafts, and other areas with only radial loads

Plain

A lean mixture at high power will most likely result in:

Engine overheating and possible detonation

Sea-level boosting refers to:

Maintaining sea-level manifold pressure at higher altitude

Specific gravity is defined as:

The ratio of a substance’s weight to the weight of an equal volume of distilled water at a specified temperature

During ground operation with low forward speed, an air-cooled engine tends to overheat. Which of the following design features helps mitigate this condition?

Cowl flaps and forced airflow management

An aircraft engine shows uneven cylinder temperatures, with some cylinders overheating while others remain within limits. Which of the following is the most likely cause?

Improper airflow distribution due to faulty baffles

A turbine blade utilizes internal air passages and film cooling. Compared to external cooling alone, what is the main advantage of this method?

It provides more effective heat removal from critical components

Which engine parameter provides the most reliable indication for assessing both the mechanical condition of turbine components and the overall operating status of a turbine engine during operation?

Exhaust gas temperature (EGT), as it indicates thermal stress and combustion efficiency

Most compressor blades are secured with this to prevent them from backing out of the slot

Pin and lock tab

An aerodynamic stall occuring in compressor sections

Compressor stall

A situation where the engine lights normally but fails to run up to idle. If this condition is allowed to persist, damage is likely and should be shut down.

Hung stall

From a thermal efficiency, weight, and size perspective, this combustor is the most efficient

Annular Combustor

When an engine turbine stator was being assembled, it was observed that there are multiple gaps per shroud. Is this normal?

These are intentional expansion joints and are left as is

A turbine blade that uses aerodynamic action to turn the disk

Reaction

To extract as much energy as possible, the exhaust nozzle of a subsonic turbofan should be shaped

Convergent

Bearings used to support Turbofan main rotor shafts

Roller

A Bell 412 has two turboshaft engines that do not produce max power unless one is inoperative. This is an example of a/an

Derated Engine

If a probe is installed between the combustion chamber and turbine section, The probe measures

TIT

An Airbus A320 is parked at a remote aerodrome with no external electrical power available. Prior to engine start, the Auxiliary Power Unit (APU) must be started to supply electrical and pneumatic power. Which of the following provides the initial electrical power required to start the APU?

Aircraft main DC battery

In a gas turbine engine operating on the ideal Brayton cycle, heat addition in the combustion chamber occurs under which condition?

At approximately constant pressure, resulting in a significant increase in specific volume

Which of the following correctly represents the standard reference fuels used to define octane rating?

Heptane and Iso-octane

In a four-stroke reciprocating engine, the inlet valve is opened slightly before top dead center (TDC) during the exhaust stroke. What is the primary purpose of this valve timing arrangement?

To improve volumetric efficiency by promoting better cylinder filling through valve overlap

For a naturally aspirated reciprocating aircraft engine operating at a constant power setting, how does an increase in outside air temperature affect the specific fuel consumption (SFC)?

It increases due to reduced air density and decreased engine efficiency

A turbocharged reciprocating aircraft engine is capable of maintaining sea-level manifold pressure up to a certain altitude. What is the term used to describe the maximum altitude at which this condition can be maintained?

Critical altitude

Backfiring through the induction system of a reciprocating aircraft engine is typically associated with improper combustion timing in relation to valve operation. Which of the following conditions is most likely to cause this phenomenon?

Excessively lean mixture causing slow flame propagation into the intake system

A naturally aspirated (unsupercharged) reciprocating aircraft engine operates at full throttle while climbing from sea level to higher altitude, with engine RPM held constant. What is the most likely effect on engine power as altitude increases?

Power decreases due to reduced air density resulting in less mass of air entering the cylinders

Detonation in a reciprocating aircraft engine is strongly influenced by the fuel’s resistance to auto-ignition. Which of the following conditions is most likely to promote detonation during engine operation?

Use of fuel with insufficient octane rating for the engine

Consider the following statements regarding abnormal combustion in a reciprocating aircraft engine: 1. Preignition occurs when the fuel–air mixture ignites before the spark due to hot spots within the combustion chamber. 2. Detonation occurs when the unburned end-gas ahead of the flame front auto-ignites after normal ignition has occurred. Which of the following is correct?

Both statements 1 and 2 are correct

An ideal gas of 0.7 kmol undergoes an expansion isothermally at 500k from 0.3 to 0.6 cubic meter. Find the work done.

2017 kJ

What type of compressor utilizes a series of low-pressure-rise stages to achieve a high overall pressure ratio while maintaining a small frontal area suitable for high-speed flight?

Axial

In a four stroke reciprocating engine, the clearance colume is 70 cubic cm. and the swept volume is 570 cubic cm. What is the compression ratio?

9

In a four stoke reciprocating engine, the clearance volume and swept volume are 70 and 570 cubic cm, respectively. What is the compression ratio?

9.14:1

The indicated mean effective pressure of an aircraft engine is 8 bar. If its bore and stroke are 150 mm and 180 mm, respectively, and it has 8 cylinders running at 2000 rpm, calculate the indicated horsepower.

339.29 kW

In a reciprocating aircraft engine, excessively advanced spark timing can negatively affect engine performance and durability. If ignition occurs too early during the compression stroke, what is the most likely result?

Peak cylinder pressure develops prematurely, increasing the likelihood of detonation, overheating, and mechanical stress on engine components.

The mass of a system is 2 kg. If the internal energy of this system is U, what is the specific internal energy of this system?

U/2

The temperature of an ideal gas remains constant while the absolute pressure changes from 103.4 kPa to 827.2 kPa. If the initial volume is 80 liters, what is the final volume?

0.01 cu m

An ideal gas with specific gas constant equal to 395.7 ft-lb/lb-deg R and a ratio of specific heats equal to 1.53, undergoes a reversible constant pressure process during which 465 Btu are added to 4.5 lb of the gas. The initial temperature is 96 deg F. Calculate the change in entropy (in Btu/deg R)

0.79

The position of the piston when it forms the smallest volume in the cylinder

Top dead center

A gas turbine engine accelerates four times the mass of air while maintaining the same increase in exhaust velocity. What happens to the momentum thrust?

It quadruples

The cross sectional area of the air annulus is reduced as it approaches the combustion chamber:

To maintain the speed of the air entering the engine.