In this study, three volutes (circular cross section with tangential inlet location, circular cross section with symmetrical inlet location, and semi-circular cross section with tangential inlet location) with the same impeller were investigated using the computational fluid dynamics. The high complexity of the flow in the centrifugal compressor volute makes the CFD modelling very difficult, only steady state flow is investigated, the choose of the volute geometry is made on the base that two geometrical parameters, which affect the overall performance and operating range, are studied at the same time , and which are:
- the shape of cross section of the volute (comparing the circular and semi-circular cross section)
- the location of the volute inlet (comparing the tangential inlet and the symmetrical inlet)
From the comparison between different designs, the following conclusion can be achieved:
1- The modification of the volute cross section shape, affects the operating range more than the peak efficiency.
2- The modification of the volute inlet location impacts the peak efficiency more than the operating range.
3- Higher peak efficiency, is observed in the case of tangential inlet.
4- Wider operating range is observed in the case of modified circular case.
5- Non-uniform pressure is observed at high flowrates.
Future work of the three configurations should be focused on the effect of the volute throat and tongue position on the whole compressor performance. The computational model also needs to be improved to reduce the error at high mass flowrate in order to get a better whole compressor performance prediction. In addition, the unsteady problem should be investigated.