The diffuser in a jet engine is designed to decrease the kinetic energy of the air entering the engine compressor without any work or heat interactions. calculate the velocity at the exit of a diffuser when air at 100 kpa and 30°c enters it with a velocity of 356 m/s and the exit state is 200 kpa and 90°c. the specific heat of air at the average temperature of 60°c

The velocity at the exit of a diffuser of a jet engine, when the entering velocity is 356 m/s, is 77.56 m/s.

The first law of thermodynamics, for a process the amount of energy obtained by the system and its surrounding should be equal to the amount of energy declined by the system and its surrounding.

From the first law of thermodynamics, the equation for an open system can be given as,

As the speacif heat of the air is 1.006 kJ/kg-K at 60 degree Celcius. Thus. The enthalpy of the system for the 30°C and 90°C are,

The velocity at the enter of a diffuser is 356 m/s. Thus, put the values in the above formula as,

Thus, the velocity at the exit of a diffuser of a jet engine, when the entering velocity is 356 m/s, is 77.56 m/s.

Learn more about the first law of thermodynamics here;

The exit velocity air is 77.56 m/s.

Explanation:

Specific heat of air at 60°C is about 1.006 KJ/kg-K (from standard table).

Now from first law for open system

For ideal gas h=CT

Given that °C

°C

By putting the values

So the exit velocity air is 77.56 m/s.

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.

  distance on the y-axis and time on the x-axis.

explanation:

the instantaneous velocity = change in position/time taken

the slope of the graph should give instantaneous velocity.

  slope of a graph = change in value of y -axis / change in values of x -axis

  comparing both the equations

    change in value of y -axis = change in position

  change in values of x -axis = time taken

so position values should be on the y axis and time values should be on the x axis.

distance on the y-axis and time on the x-axis.