The Design, Development and Evaluation of 3D Aerofoils for High Speed Axial Compressors: Part 2 — Simulation and Comparison With Experiment

Abstract

The focus of this paper is to report on measurements from and simulation of Cranfield University’s 3-stage high-speed axial compressor test rig. This newly built rig is supported by European Commission funding and has tested a set of conventionally stacked 2D rotor and stator blades (Reference 1). The results were used to evaluate and to assess the performance of several commercially available CFD codes leading to the collaborative design of an advanced three-dimensional blade set. The philosophy behind the advanced design is described. The datum test results show that the state of the art, highly loaded, datum compressor is well matched with limited potential for loss reduction. A comparison is made between the measured results and a series of numerical analyses using the various CFD codes. Although the codes showed reasonable qualitative agreement with each other and the measured data, there were significant differences in the predicted performance of the datum build. Further the codes were unable to grade candidate redesigns consistently on a quantitative basis and therefore increased the difficulty of selecting suitable ‘3d’ features. Generic studies involving sweep, lean and recambering are used to evolve a design philosophy for the advanced three-dimensional design. Over cambering of the end-wall sections, coupled with a suitable stack of the blades, enables the blade count to be reduced. In the presence of a clearance combinations of sweep and lean are used to modify the loading in the clearance gap, thereby influencing the associated losses. The application of three-dimensional features redistributes the flow. The opportunity is therefore taken to rematch the sections based on the predicted results of the CFD codes. The above philosophy is used in the redesign of the datum compressor. Overall characteristics and exit traverse results from the test of the advanced build are compared to those from the datum build.

Design optimisation of a regenerative pump using numerical and experimental techniques

“…In the current study, the experimental results and the CFD predictions are within 3 per cent (Figures 18 and 19), indicating that the meshing strategy was reasonable (Woollatt et al, 2005). The examples referenced above, Ex 143 (2001) and Ex 164 (2001), at best achieved a 7 per cent matching.…”

“…The random scatter was evaluated from repeatability tests and sensitivity analyses. The systematic inaccuracy due to aggregate systematic errors in transducers and changes in performance due to build‐to‐build differences are difficult to evaluate (Woollatt et al , 2005). To achieve this, it is essential that the data acquisition system incorporates procedures which evaluate the quality of the data as it is acquired.…”

Numerical and Experimental Design Study of a Regenerative Pump

“…In Fluent application briefs [18][19][20] water pump MRF simulations made use of tetrahedral and hybrid meshes of similar scale. In the current study the experimental results and the CFD predictions are within 3%, indicating that the meshing strategy was reasonable, [12]. The examples referenced above [18,20] at best achieved a 7% matching.…”

“…The random scatter was evaluated from repeatability tests and sensitivity analyses. The systematic inaccuracy due to aggregate systematic errors in transducers and changes in performance due to build-to-build differences are difficult to evaluate [12]. To achieve this it is essential that the data acquisition system incorporates procedures which evaluate the quality of the data as it is acquired.…”