A Practical Approximate Method to Predict Adjusting Performance of a Centrifugal Compressor Stage With Inlet Guide Vane

This paper has proposed a method for predicting an adjusting performance curve family of a centrifugal compressor stage with the inlet guide vane (IGV). The method can be separated into two steps. In the first step, a centrifugal compressor model stage is selected as a basic model stage to build the basis of prediction. Both the ordinary performance curve of the model stage without IGV and the adjusting performance curve family of the model stage at various setting angles of the IGV are obtained by experiments. Then, using the ordinary performance curve as a criterion, a non-dimensional mathematical relationship is set up between the ordinary performance curve and each curve in the adjusting performance curve family. In the second step, based on the relationship established above, a prediction is made for the adjusting performance curve family of another centrifugal compressor stage with an IGV. For this prediction, two conditions must be satisfied: 1) The adjustment must be done using the IGV of the same type as used in the first step; 2) The ordinary performance curve of the predicted model stage must have been obtained experimentally. By applying the method, a prediction was carried out for the IGV adjusting performance curve family of a centrifugal compressor stage. Comparison between the predicted results and experimental results shows that although there is relatively great discrepancy between the basic model stage and the predicted stage under the mechanical geometric construction and operating conditions, the two results agree well in most of the areas of the adjusting performance curve family. There are only greater errors of predicted results in areas of large IGV setting angle. Although the current method has some deficiencies, it still possesses some strength featuring simplicity, convenience and reliability, thus providing a practical approximate prediction method available for the centrifugal compressor manufacturers that have the model stage database, but lack the APCF for the model stages with IGV.Copyright © 2011 by ASME