DESIGN AND PERFORMANCE OF VANELESS VOLUTES FOR RADIAL INFLOW TURBINES.2. EXPERIMENTAL INVESTIGATION OF THE MEAN LINE PERFORMANCE ASSESSMENT OF EMPIRICAL DESIGN PARAMETERS

The non-dimensional design procedure described in Part 1 assumed a one -dimensional compressible flow and as such relied on the empirical spe cification of the dissipation of angular momentum, the dissipation of energy and the deviation of the swirling flow from that of a free vort ex. This was based largely on data available in the published literatu re. In order to develop and substantiate the empirical procedures furt her an experimental study was carried out in parallel with the develop ment of the design procedure. The experimental investigation described here had the specific objective of assessing and developing appropria te empirical models and coefficients for application to the design pro cedure. The study concentrated on the application of a five-hole probe located in the centre of the volute passage and at a series of azimut h angles around the discharge. The probe provided stagnation and stati c pressure measurements, from which the gas velocity was derived, toge ther with the flow angle. When taking measurements at the volute disch arge a stationary dummy rotor was used to carry the five-hole probe.