It has recently been reported that noise generated in screw compressors can by reduced by modifying the shape of the high pressure port to minimize gas pulsations in the discharge chamber. This paper describes a simulation mode developed to predict the optimum form of this. The procedure used was to simulate the flow in three dimensions within the discharge chamber, using CFD, and to couple this with flow simulations in the working chamber and outlet reservoir, based on one dimensional models.
The model takes into account the real shape of the discharge port. By its use it is possible to predict gas pulsations in the discharge chamber for different shapes of the discharge port and thereby optimise the port shape to reduce the compressor noise. Results derived from it show good agreement with experimental values.