Aerodynamic Performance on Centrifugal Compressor (lesson five)

RETURN GUIDE VANE

The operational principle is similar to the one of Inlet Guides Vane. The previous part of the vane should be curves owing to the fact that they receive the gas from the previous compression stage in tangential direction, the angle usually fluctuates between 45 degrees where it starts the Stonewall and 75 degrees where it begins Surge. The way and behavior of the back part of these vanes are similar to Inlet Guide Vanes them.

Aerodynamic Performance of Centrifugal Compressors LESSON (FOUR)

INLET GUIDE VANE
Receive the flow of the volute of entrance and it take radial towards the center until the entrance of the first impeller. They are three types of vanes according to the way of his final part. It you can observe a transversal cut in the figure of each one of these front teeth or vanes. From the volute, the gas comes with an almost null speed for dimensions of the volutes, the gas takeover the radial direction to the entrance of vane, them but to the exit of these direction depends on the way of the same. Can be radial as in the type 2, the meaning held out against the rotation if is of the type 3 or in meaning of rotation if is of the type 1.
We can observe the effect of the Guide Vanes in the graph, in function to the speed triangle to the entrance. A Guide vane is represented in the intermediate graph with zero exit angle. W1 represents the relative speed, U1 represents the tangential speed, C1 is the absolute speed of the gas and Beta 1is angle of vane. For being straight does not be tangential component of CU1, using the Theorem of Euler, the head will be U2 multiply C1. On the other hand if the vane this crooked one in connection with the rotation meaning (type 1), will have his tangential component, defined by the angle Alpha which consequently the absolute speed will be lower, reducing Head and flow. Converse Case happens in the vanes (type three), where the Head and the flow are increased.