Temperature and pressure change in a diffuser

Overall, you will need to use a combination of equations and thermodynamic properties to determine the exit pressure, temperature, and mass flow rate. In summary, the conversation discusses using the Bernoulli equation to calculate the exit pressure and the need for additional information, such as the type of fluid, to determine the exit temperature. Multiple equations and thermodynamic properties may be needed to determine all the desired parameters.
  • #1
LauraMorrison
26
0
I am totally stuck on this question. It is about a diffuser and it does not tell you what fluid is running through the system.

"A diffuser has the following inlet conditions:

p1=100kPa
T1=300K
Velocity=200m/s
Area=100m2
Specific Volume=1.6445m3/kg

The exit velocity is 20m/s

Calculate the exit pressure, temperature and the mass flow rate. (Assume adiabatic operation)."


Would it be correct to use the Bernoulli equation, taking into account enthalpy and kinetic energy changes, to calculate the exit pressure? This is assuming density is constant.

I am not aware of any equation which will allow me to work out the exit temperature without knowing what substance is actually contained in the system.

Any help with this would be very much appreciated,
Thanks
 
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  • #2
in advance.Yes, you can use the Bernoulli equation to calculate the exit pressure. The exit temperature will depend on the particular substance running through the system and its particular thermodynamic properties. If you know the type of fluid, you can use the appropriate thermodynamic relations to calculate the exit temperature.
 

Related to Temperature and pressure change in a diffuser

1.

What is a diffuser?

A diffuser is a device used to slow down and evenly distribute a fluid, typically air, as it passes through a confined space. The most common example is the diffuser found on the end of a hair dryer, which helps to spread out the air and make it less intense.

2.

Why does temperature change in a diffuser?

Temperature changes in a diffuser because of the process of adiabatic heating or cooling. As the fluid, such as air, is compressed and slowed down in a diffuser, its molecules collide with each other and transfer energy, leading to a change in temperature. This is also known as the Bernoulli effect.

3.

What is the relationship between temperature and pressure in a diffuser?

The relationship between temperature and pressure in a diffuser is inverse. As the temperature increases, the pressure decreases, and vice versa. This is due to the ideal gas law, which states that as the temperature of a gas increases, its pressure decreases if the volume remains constant.

4.

How does pressure change in a diffuser?

The pressure changes in a diffuser due to the process of adiabatic compression. As the fluid, such as air, is slowed down and compressed in a diffuser, its pressure increases. This is because the energy of the fluid is conserved, and as it is compressed, the same amount of energy is now contained in a smaller volume, leading to an increase in pressure.

5.

What factors can affect temperature and pressure change in a diffuser?

Several factors can affect temperature and pressure change in a diffuser, including the speed of the fluid, the shape and size of the diffuser, and the properties of the fluid itself. The speed of the fluid and the shape and size of the diffuser will determine the amount of adiabatic heating or cooling that occurs, while the properties of the fluid, such as its density and specific heat, will affect how much the temperature and pressure change.

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