No abstract

In a common project ABB Fläkt Industri AB, Sweden, and ABB Turbo Systems Ltd., Switzerland, developed a Q3D design system for low Mach number axial fans. In order to validate the Q3D-calculations and the customized loss correlation, the flow field of an industrial high-pressure boiler fan was investigated experimentally. The examined single stage fan is equipped with hydraulically adjustable rotor blades, non-profiled guide vanes and an annular diffuser. Varying the stagger angle between 34° and 76° allows operating the fan over a wide range of volume flows. Experiments and calculations cover the entire stable operating range. Flow field traverses by means of hot film anemometry and pneumatic total pressure Kiel probes at different sections within the rotor/vane configuration, combined with axially and tangentially distributed static pressures tabs and fix mounted Kiel probes, allowed a deep insight in the flow behavior. The fast response capability of the hot film anemometry was used to measure the flow field downstream of the rotor in detail. Additionally, flow field visualizations inside the guide vane channel based upon a TiO4/Oil-paint technique completed the experimental fan investigation. The Q3D system is based on coupling the Euler codes MISES (S1) and MTFlow (S2), both developed at MIT. Loss models were implemented to account for profile losses, leakage losses and endwall losses. Near wall viscous effects are considered by boundary layer modeling. The investigations show that the S1/S2 Euler solvers behave well even in case of Mach numbers below 0.03. S1 convergence problems arise for off-design cases because of unfavorable incidence angles. The fully automated Q3D systems allows calculating fan performance charts with low turnaround time in good agreement with the measurement.