The size and fuel consumption as well as the pollutant emissions of gas turbine combustors have to be significantly reduced in the future, which brings new challenges to the design of combustors. An innovative gas turbine combustor, named Short Helical Combustor (SHC) has been proposed by B. Ariatabar et al. The major feature of SHC is that the swirling flow originated from a single swirler is only restricted by one side in circumferential direction which is greatly different than traditional combustors. The present work of this paper is to investigate the features of the single-restricted swirling flows in a model SHC by adjusting the axial distance (L) between adjacent swirlers. The relevant results show that, 1. In non-reacting flows, with the increase of L, the flow field downstream the swirler successively presents four modes: traditional mode, single-vortex mode, critical mode and double-vortices mode. When L = 0, a pair of counterrotating vortices exists in combustor. When 0.27H < L < 0.67H, only one vortex exists downstream the swirler. When 0.68H < L < 1.73H, another counter-rotating vortex gradually appears close to the unrestricted side. 2. With the increasing of L, the aerodynamic boundary is gradually formed on the unrestricted side in the reacting and non-reacting flows, which is the primary reason for the formation of vortex B. 3. The specific value of L of critical mode in reacting flows is larger than that in non-reacting flows because the gas expansion caused by combustion goes against the formation of aerodynamic boundary. 4. The velocity direction of the flows downstream the recirculation varies at different vortex modes in reacting and non-reacting flows. In non-reacting flows, the flow direction changes almost 180° as L is increased from 0.27H–1.73H. In reacting flows, the flow direction gradually varies from circumference to axis as L is increased from 0.27H–1.73H. The present work details the feature of the flow field in SHC, which is great meaningful to the design and improvement of the combustor.

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