inlet guide vanes, 1 or more?
inlet guide vanes, 1 or more?
(OP)
In our plant we have different compressors, used for air compression and compression of our products.
We have a few integrally Geared Compressors. They have all different discharge pressures, capacity and they are used for different products (air, oxygen, nitrogen)they are all from the same mgf. But they're from different years.
Now we've noticed that some have Inlet Guide Valves on every stage, and some only at the inlet.
Can someone explain why this is? Based on what theory will a mgf choose to use 1 IGV of multiple IGV?
Thanks,
Cryo
We have a few integrally Geared Compressors. They have all different discharge pressures, capacity and they are used for different products (air, oxygen, nitrogen)they are all from the same mgf. But they're from different years.
Now we've noticed that some have Inlet Guide Valves on every stage, and some only at the inlet.
Can someone explain why this is? Based on what theory will a mgf choose to use 1 IGV of multiple IGV?
Thanks,
Cryo
"Math is the ruler of your potential succes...."





RE: inlet guide vanes, 1 or more?
This problem may be resolved by employing variable stator (VSVs) and variable inlet guide vanes (VIGVs). These variable stators (usually fitted to the front or LP stages) are closed at lower compressor speeds thus reducing the loading on the front stages hence preventing stalling of theses stages. Furthermore, the closure of these stators also reduces the flow capacity through the compressor thus reducing the velocity in the HP stages of the compressor hence preventing the choke conditions in this part of the compressor. However, at maximum compressor speeds when maximum capacity is needed the stators are fully open. The movement of each stator may be different and the largest movement occurs in the VIGV and the front stage VSV.
For low pressure ratio machines the stalling discussed above is unlikely to occur and variable stators are not present. However, a variable inlet guide vane may be fitted to control the flow particularly for a constant speed machine.
RE: inlet guide vanes, 1 or more?
Our compressors are all running at constant speed. The capacity is controlled by the IGV's.
The compressors have all different work ranges. (flow and pressures)
For example, we have 2 Nitrogen compressors. Both have a discharge pressure of 80 bar.
1 has a working range between 30000Nm3/h-55000Nm3/h, 8 stages, and IGV's at all stages.
the other one has a range of 55000Nm3/h-80000Nm3/h 7 stages, and only a IGV at the first stage.
They're both integrally geared type compressors.
Greetings
Cryotechnic
"Math is the ruler of your potential succes...."
RE: inlet guide vanes, 1 or more?
VBR
GTSIM
RE: inlet guide vanes, 1 or more?
Cryotechnic
"Math is the ruler of your potential succes...."
RE: inlet guide vanes, 1 or more?
VRB
GTSIM
RE: inlet guide vanes, 1 or more?
sorry, now I'm getting it, you was talking AXIAL compressors ONLY.
Your right, the compressors in my last post are not from an AXIAL type.
The compressors I'm talking about are radial type compressors.
In fact, we do have a axial/radial compressor in our plant. This one has the variable stator you're talking about ont he axial part of the machine. The machine is a single shaft axial/radial type, we use this one to compress air to 5,5bar. (max 180000Nm3/h)
Thanks
Cryotechnic
"Math is the ruler of your potential succes...."
RE: inlet guide vanes, 1 or more?
Thanks for the update. I am not very familiar with radials however I understand that they can use variable stator in the discharge side to improve the turn down. I trust this helps.
VBR
GTSIM