Effect of NGV Lean Under Influence of Inlet Temperature Traverse

Abstract

One of the most widely studied parameters in turbine blade shaping is blade lean, i.e. the tangential displacement of spanwise sections. However, there is a lack of published research that investigates the effect of blade lean under non-uniform temperature conditions (commonly referred to as a ‘hot-streak’) that are present at the combustor exit. Of particular interest is the impact of such an inflow temperature profile on heat transfer when the NGV blades are shaped. In the present work a computational study has been carried out for a transonic turbine stage using an efficient unsteady Navier-Stokes solver (HYDRA). The configurations with a nominal vane and a compound leaned vane under uniform and hot-streak inlet conditions are analysed. After confirming the typical NGV loading and aero-loss redistributions as seen in previous literature on blade lean, the focus has been directed to the rotor aerothermal behavior. Whilst the overall stage efficiencies for the configurations are largely comparable, the results show strikingly different rotor heat transfer characteristics. For a uniform inlet, a leaned NGV has a detrimental effect on the rotor heat transfer. However, once the hot-streak is introduced, the trend is reversed; the leaned NGV leads to favourable heat transfer characteristics in general and for the rotor tip region in particular. The possible causal links for the observed aerothermal features are discussed. The present findings also highlight the significance of evaluating NGV shaping designs under properly conditioned inflow profiles, rather than extrapolating the wisdom derived from uniform inlet cases. The results also underline the importance of including rotor heat transfer and coolability during the NGV design process.

Influence of Swirl Clocking on the Performance of Turbine Stage with Three-Dimensional Nozzle Guide Vane

“…bomachinery research. Comprehensive results from experiments and CFD a enhance the understanding of the root cause [3][4][5][6][7][9][10][11][12][13][14][15][17][18][19][20][21][22][23][24][25][26][27][28][29]. Furthermor optimization approach is being applied to offer more complicated control rameters [8,16,30].…”

“…It has been reported that the straight lean and compound lean can reorganize the vortices and reduce the secondary flow loss. As a result, the secondary flow loss decreased remarkably by using appropriate leaned blades [12][13][14][15][16]. The sweep commonly occurred because the meridional passage of the main annulus is not typically at a constant radius, whereas the NGV is stacked on a near radial line in the meridional views.…”

“…It has been almost twenty years since the advanced computational fluid dynamics (CFD) and experimental approach have been brought into turbomachinery research. Comprehensive results from experiments and CFD are reported to enhance the understanding of the root cause [3][4][5][6][7][9][10][11][12][13][14][15][17][18][19][20][21][22][23][24][25][26][27][28][29]. Furthermore, the design optimization approach is being applied to offer more complicated control of design parameters [8,16,30].…”

Clocking and Potential Effects in Combustor–Turbine Stator Interactions

“…As the first step, the combustion chamber is designed, resulting in a flow parameter and temperature distribution at the outlet as shown by [3,4]. Then, the turbine is designed according to the boundary conditions defined at the combustor-turbine interface [5,6]. A disadvantage of this approach is a very weak interaction between the combustor and the turbine, which is recognized to have an important effect on the durability and performance of the first stage of the gas turbine.…”