Faculty Publications
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Item Numerical Investigation on Effects of Profiled Endwall Over Purge Flow in Linear Turbine Cascade(Springer Science and Business Media Deutschland GmbH, 2020) Babu, S.; Kiran, K.N.; Tom, J.K.; Anish, S.This paper describes the combined effects of purge flow and non-axisymmetric endwall profiling on the aerothermal performance of a linear turbine cascade. Purge slot with 45° ejection angle and three different endwall profiles, with varying hump to dip height, are analyzed. Performance of profiled endwall is compared with the non-profiled case. Reynolds-averaged Navier–Stokes (RANS) equation with SST turbulence model is used for numerical simulation. The analyzed results explore the demerits of current endwall profiles and how the transverse movement of weaker boundary layer fluid from the hub-pressure side corner enhanced. Compared to base case, endwall profiling enhanced the overturning and secondary flow kinetic energy at cascade exit. Apart from this, the profiled cases are providing very effective endwall protection compared to non-profiled purge case. © 2020, Springer Nature Singapore Pte Ltd.Item An investigation on the effect of pitchwise endwall design in a turbine cascade at different incidence angles(Elsevier Masson SAS 62 rue Camille Desmoulins Issy les Moulineaux Cedex 92442, 2017) Kiran, K.N.; Anish, S.This paper describes the effects of non-axisymmetric endwall profiling on the aerodynamic performance of a linear turbine cascade at different incidence angles. The sinusoidal profiling is carried out with constant profile curvature along the mean streamline path. Three different profiles, with varying hump to dip height, are analyzed numerically and the performances are compared with the planar profile. Reynolds Averaged Navier Stokes (RANS) equations are solved in their conservative form using Finite Volume Method with SST turbulence model. The calculated results indicate that the profiled endwall minimizes the lateral movement of weaker boundary layer fluid from the hub-pressure side corner. In comparison with planar case, the flow deviations are largely contained with endwall profiling but closer to the endwall it enhances the overturning and secondary flow kinetic energy. The reduction in loss coefficient is estimated to be 1.3%, 8.7% and 38% for incidence angles of ?10°, nominal and +15° respectively. The sinusoidal profiling has brought down the pitch averaged flow deviation and secondary flow kinetic energy at nominal and positive incidence angles but the impact is insignificant at negative incidence. Profiling minimizes the rolling up of the passage vortex and makes the passage vortex to migrate closer to the endwall. This flow modification brings down the losses in the core flow but enhances the losses near the endwall. © 2017 Elsevier Masson SASItem Computational investigation on secondary flows in a linear turbine cascade with tapered dual fence(Korean Society of Mechanical Engineers, 2019) Kiran, K.N.; Babu, B.; Anish, S.The focus of the present work is to minimize the secondary flow losses inside a linear turbine cascade by means of a novel design of streamwise dual fence. The leading edge and trailing edge of the fences have been modified so as to reduce the total pressure loss coefficient in the passage. The study has been carried out computationally based on RANS simulations with SST turbulence model. Numerous simulations have been undertaken with single fence and dual fence models and compared with the base case model. The dual fence model with tapered trailing edge exhibits significant loss reduction compared to the base case. A suitable fence height ratio (FHR) has been identified for the dual fence model. The FHR = 2 configuration reduces the secondary flow kinetic energy by 78 % within the blade passage and it reduces the exit angle deviation significantly throughout the span. Detailed flow field analysis has been carried out to understand the physical mechanism behind the loss reduction with dual fence models. It is observed that fence-1 breaks the pressure side leg of the horse shoe vortex at the beginning of their formation itself. The radial penetration of the suction side leg of the horse shoe vortex is restrained by fence-2. These combined effects prevent the formation and mixing of two prominent loss core regions thereby avoiding the accumulation of low energy fluid near the suction side of blade. © 2019, KSME & Springer.