Centrifugal compressors some details on work done and vane angles.

In summary, there is a question regarding the use of stagnation temperatures in the derivation of Euler work for a centrifugal compressor. The use of static temperature instead of stagnation temperatures in a solved problem is also questioned. The reason for using T02s= T01(P02/P01)^(γ-1/γ) is also unclear, as there is no actual adiabatic isentropic process between the initial and final stagnation temperatures. Additionally, it is mentioned that the inlet air angle for a radial vane centrifugal compressor cannot be 90 degrees, as this would cause the air to slide off the vane without rotating it. A solution or explanation is requested.
  • #1
Urmi Roy
753
1
1. As far as the derivation goes, Cp(T02-T01)= Euler work= U2Cx2 in a centrifugal compressor...
where T01 and T02 are the stagnation temperatures...however, in a solved problem in my book, it writes:

Cp(T2-T1)= Euler work= U2Cx2...and therefore uses static temperature instead of stagnation temperatures...is this an error?

2. There is no actual adiabatic isentropic process between the initial stagnation temperature (T01) and the final isentropic stagnation temperature T02s...thenwhy are we allowed to use

T02s= T01(P02/P01)^(γ-1/γ)?

3. Is it true that the inlet air angle, alpha for a radial vane centrifugal compressor CANNOT be 90 deg?

(My teacher said that it always has to be< 90, since otherwise the liquid/air in compressor would simply slide off the vane without making the vanes rotate... )
 
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  • #2
Someone please please please help!
 
  • #3
Could someone at least give me a clue? Its very frustrating to have to wonder about these things everyday and not find a solution...
 

1. What is a centrifugal compressor?

A centrifugal compressor is a type of dynamic compressor that uses centrifugal force to compress gas or air. It consists of a rotating impeller and a stationary diffuser, which work together to increase the velocity of the gas and then convert it into pressure.

2. How do centrifugal compressors work?

Centrifugal compressors work by accelerating the gas or air through the impeller blades, increasing its velocity and kinetic energy. This high-velocity gas is then directed into the diffuser, where the kinetic energy is converted into pressure. The compressed gas is then discharged through the outlet of the compressor.

3. What is the role of vane angles in centrifugal compressors?

Vane angles, also known as blade angles, play a crucial role in the performance of centrifugal compressors. They are designed to control the flow of gas and ensure that it enters the impeller at the correct angle for efficient compression. The vane angles also help to increase the velocity of the gas and improve the overall efficiency of the compressor.

4. What types of vane angles are used in centrifugal compressors?

There are two main types of vane angles used in centrifugal compressors: inlet guide vanes and discharge guide vanes. Inlet guide vanes are located at the inlet of the impeller and are used to adjust the flow of gas into the impeller. Discharge guide vanes are located at the outlet of the impeller and are used to control the flow of compressed gas as it exits the impeller.

5. What factors affect the performance of centrifugal compressors?

The performance of centrifugal compressors is affected by several factors, including the rotational speed of the impeller, the vane angles, the type and properties of the gas being compressed, and the operating conditions such as temperature and pressure. Maintenance and proper installation of the compressor also play a significant role in its performance.

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