Scaling of the two-phase flow downstream of a gas turbine combustor swirl cup: Mean quantities

A production gas turbine combustor swirl cup and a 3x-scale model, both featuring co-axial, counter-swirling air streams are characterized at atmospheric pressure and in the absence of reaction. Spatially-resolved measurements of continuous phase (gas in the presence of spray) and droplet size and velocity are acquired downstream of the production and 3x-scale swirl cups by using two-component phase Doppler interferometry. The effect of scale on the behavior of the continuous phase and droplets is investigated by comparing the continuous phase velocity and droplet size and velocity at geometrically analogous positions. The continuous phase flow field scales well at the exit of the swirl cup. Farther downstream, differences occur which are due to disparity in entrainment. The droplet velocities scale reasonably well, but the sizes show some differences. However, the difference in size is less significant than it is between the two atomizers in the absence of the swirl cup assemblies