Centrifugal pumps are used in many applications in which non-Newtonian fluids are involved, such as food industry and oil&gas applications, producing the pump performance derating. In order to give an overview of pros, cons of the different analytical approaches for pump performance derating a literature review on the most significant advances in this topic will be carried out. Moreover to deepen the knowledge about the internal flow and rheological behavior inside the centrifugal pumps working with non-Newtonian fluids, a detailed CFD analysis of two different pumps will be carried out. The analysis will be focus on the apparent viscosity correction involved in the performance derating with analytical methods and the effects of different types of fluid. Moreover the comparison of the results with two pumps with very different typology, field of application, and dimensions will help to generalize the meaning of the analysis.

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In this paper, a test rig for experimentation on a micro gas turbine is presented. The test rig consists of a micro gas turbine Solar T-62T-32, which, coupled with a 50 kVA alternator, can supply electrical energy to a calibrated resistive load bank. Particular attention is paid to the design of the inlet duct for the mass flow rate measurement. The basic issue was to create the intake duct for a micro gas turbine (MGT) test rig, in order to provide precise data about the mass flow rate and the thermodynamic air characteristics in the MGT inlet section. The inlet duct is also designed in order to allow future tests on inlet cooling technologies. The MGT is incorporated in a chassis for noise reduction, the dimensions of which are 540 mm (height), 570 mm (width) and 940 mm (length). These small dimensions lead to problems with the insertion of the duct. Moreover, the intake of the compressor is not axial but radial, and this means that a volute must be foreseen to convey the flux into the MGT. Several shapes of volute are analyzed in this paper, considering the effects on the pressure loss and the induction of turbulence. The challenge was to develop a fluid-dynamically efficient duct with the hindrance of a very small available space between the compressor casing, the gearbox and the fuel pipes inside the narrow noise-reduction chassis. The mass flow rate will be computed by means of the differential static pressure between the upstream and the downstream section of a Venturi tube. The choice of a Venturi was due to the fact that it produces a pressure loss lower than any other device, such as orifice plates or other nozzle shapes. Furthermore, the expected mass flow rate would lead to high fluid speeds and, as a consequence, the diameter ratio between the duct and the throat of the Venturi was chosen to be as high as possible.