Streamline Curvature Approach Research Articles

Performance Prediction of Transonic Axial Compressors Using Improved Streamline Curvature Approach

The paper describes an improved streamline curvature approach (SLC) to the flow field analysis and performance prediction of transonic axial compressors. The previous research concerning the incidence angle, deviation angle, and total pressure loss models is discussed. Many semi-empirical correlations and curve fits were based on two-dimensional cascade experiments, resulting in evident discrepancy between the calculated results and the actual experimental data, especially in endwall regions. The approach suggested in this study makes improvements embodied mainly in the deviation revision taking into account the endwall effect, which acts as the combination of aerodynamic and geometry parameters. The program is applied to predict the performance of two transonic axial compressors, a single-stage compressor NASA Stage37 and a two-stage fan TP1493. The characteristic curves and spanwise aerodynamic parameter distributions under design and off-design conditions are illustrated. Moreover, the results acquire satisfactory precision compared with the experimental data. This through-flow method is verified as an reliable and applicable tool for the aerodynamic design and analysis of transonic axial compressors during the design stage.

Development and application of a throughflow method for high-loaded axial flow compressors

In this paper, a novel engineering platform for throughflow analysis based on streamline curvature approach is developed for the research of a 5-stage compressor. The method includes several types of improved loss and deviation angle models, which are combined with the authors’ adjustments for the purpose of reflecting the influences of three-dimensional internal flow in high-loaded multistage compressors with higher accuracy. In order to validate the reliability and robustness of the method, a series of test cases, including a subsonic compressor P&W 3S1, a transonic rotor NASA Rotor 1B and especially an advanced high pressure core compressor GE E3 HPC, are conducted. Then the computation procedure is applied to the research of a 5-stage compressor which is designed for developing an industrial gas turbine. The overall performance and aerodynamic configuration predicted by the procedure, both at design- and part-speed conditions, are analyzed and compared with experimental results, which show a good agreement. Further discussion regarding the universality of the method compared with CFD is made afterwards. The throughflow method is verified as a reliable and convenient tool for aerodynamic design and performance prediction of modern high-loaded compressors. This method is also qualified for use in the further optimization of the 5-stage compressor.

Performance prediction of transonic axial compressor based on streamline curvature method

The streamline curvature (SLC) method is still of great importance for modern compressor performance prediction. The models applied in it, such as minimum incidence, deviation and loss, affect prediction’s accuracy directly. An improved SLC approach is introduced in this paper, which is developed based on the analysis and summary of predecessor’s works. The improvement is embodied mainly in the incidence and loss, which is the result of a combination of the previous models and models’ revisions in order to consider the main effects for modern compressor cascade. A certain isolated stage axial transonic compressor is calculated by SLC method. The speed lines and span-wise aerodynamic parameters are compared with the experiment data to demonstrate the SLC approach presented in this paper.

An improved streamline curvature approach for transonic axial compressor performance prediction

An improved streamline curvature (SLC) throughflow analysis method is presented based on the predecessor's works to simulate the flow fields of a certain transonic axial compressor. The improvements of this method are embodied centrally in minimum loss incidence angle (MIA) model and total pressure loss (TPL) model that ensure accurate and reliable performance prediction at both design and off-design conditions. The improved MIA is set up as a function of inlet Mach number, solidity, thickness, camber angle, etc. according to low-speed minimum incidence angle. Therefore, TPL is divided into two parts, the first one is the minimum loss which considers the revise of Mach number and Reynolds number, and the second one is the additional loss when real incidence angle deviates from MIA. Finally, the internal flow field of a single-stage compressor is simulated. The characteristic curves and spanwise aerodynamic parameters distribution at design and off-design points are illustrated in this article. Compared to the experiment and computational fluid dynamics (CFD) data, this improved SLC method gives reasonable performance trends and generally accurate results, also the MIA and TPL models are demonstrated in this article.

An Improved Streamline Curvature Approach for Off-Design Analysis of Transonic Axial Compression Systems

A streamline curvature throughflow numerical approach is assessed and modified to better approximate the flow fields of transonic axial compression systems. Improvements in total pressure loss modeling are implemented, central to which is a physics-based shock model, to ensure accurate and reliable off-design performance prediction. The new model accounts for shock geometry changes, with shock loss estimated as a function of inlet relative Mach number, blade section loading (flow turning), solidity, leading edge radius, and suction surface profile. Data from a single-stage, isolated rotor provide the basis for experimental comparisons. Improved performance prediction is shown. The importance of properly accounting for shock geometry and loss changes with operating conditions is demonstrated.

Measured and Predicted Flow Near the Exit of a Radial-Flow Impeller

Experimental measurements are presented of the velocity field near the exit of a radial impeller with backward-curved blades. The flow pattern, and its variation with changes in the flow coefficient, are compared with numerical predictions on a blade-to-blade plane. The theoretical flow prediction method assumes inviscid flow, is essentially two-dimensional and is based on the streamline curvature approach. It does not specifically require the condition of zero absolute vorticity. The comparison with experiment indicates that the principal feature of the flow not accounted for in the inviscid model is the region of low velocity near mid-blade height on the suction surface, especially for higher blade loadings.

Streamline Curvature Computing Procedures for Fluid-Flow Problems

An attempt is made in this paper to develop forms of the equation of motion, the continuity equation, and the equations which define the fluid which are amenable to a solution by what has come to be termed “the streamline curvature approach.” The techniques were developed in their present form specifically as a result of the comparatively recent interest in the axial compressor for jet engines. Fluid fields, in general, can be considered to have different energy levels on differing surfaces, to be subject to boundary conditions which impose significant curvature accelerations, and to be rotational. An intelligent exploitation of the possibilities inherent in these degrees of flexibility can very significantly modify and improve the turbomachine; the techniques thereby become adaptable to other situations. It is part of the purpose of this paper to suggest that the technique has become sufficiently mature so that a careful appraisal of its relevance to areas other than turbomachinery is in order.