Influence of Blade Fillets on the Performance of a 15 Stage Gas Turbine Compressor

Abstract

In the modern process of the aerodynamic design of multistage compressors and turbines for jet engines as well as for stationary gas turbines, 3D-CFD plays a key role. Before building the first test rig several designs have been investigated using numerical simulations. To understand the characteristics of the individual components it is necessary to simulate their behavior in a multistage simulation and investigate for example, the single stage maps of the compressor in order to understand how the load is divided between the different parts of the compressor during throttling. Increasing computing resources allow ever more details to be incorporated in a 3D simulation. In former times only single blade rows were investigated with a high resolution of the boundary layers, whereas in multistage configurations wall functions were state of the art. Today we are able to apply Low Reynolds resolution even for multistage configurations, so the designer is required to include more and more geometrical details into the simulation. One important such feature is the fillets of rotor and stator blades. Fillets reduce the flow deflection at the endwalls and therefore the loading of the downstream blade rows. This effect is accumulated in a multistage simulation. In this paper a 15-stage compressor with additional inlet and outlet guide vane designed for a stationary gas turbine was investigated with a modern CFD tool by using a real gas approach for two speedlines. Two simulations were done: first a clean configuration with tip and hub clearances but without blade fillets; in the second simulation all rotor blades and the cantilevered stator blades were additionally modeled with fillets. The comparison of the overall global values with measurement data shows a better performance of the simulation with fillets, especially by throttling the compressor. A deeper look into the compressor shows different loads for a considerable number of single stages. The analysis of the steady multistage simulations shows that the numerical stability is reached in different regions of the machine.

Numerical assisted Design of a Variable Rotating Vane Carrier Device for Turbine Test Rigs with split Housing Structures using a Segmented Half-Ring Bearing Concept

“…The flow solver TRACE, developed by the DLR 14 , was used to conduct three-dimensional time-resolved calculations from whom steady and unsteady thermal and mechanical loads can be derived and numerically imposed on structural components of the new test rig.…”

Design optimization of a multi-stage axial compressor using throughflow and a database of optimal airfoils

“…Throughflow results are compared to simulations carried out with the 3D CFD solver TRACE (Kügeler et al, 2008;Becker et al, 2010). TRACE is developed at DLR for turbomachinery application.…”

Effects of Endwall Fillet and Bulb on the Temperature Uniformity of Pin-Fined Microchannel

“…Hoeger et al [17] analyzed the influence of the fillet and bulb on the endwall flow in the compressor cascade, and the results showed that the separation in the rear surface decreased and even disappeared under the influence of fillet structure. Kuegler et al [18] numerically found that the fillet could decrease the corner separation and enlarge the range of throttling process in multi-stage compressor. Goodhand et al [19] found that after removing the fillet, flow separation was enhanced considerably near the hub of stator blades in compressor and thus the loss was greater.…”