Session: 01-06 Inlet Distortion and Engine Operability

Paper Number: 100773

100773 - High Throughflow Design and Analysis for Streamvane Swirl Distortion Generators 

In recent years, the ScreenVane technology has developed into a mature and streamlined process that can reproduce distortion profiles to evaluate performance and aeromechanic characteristics for nonuniform flow ingesting turbofan engines and/or fan rigs at the ground testing level. The ScreenVane system consists of a wire mesh screen placed upstream and coupled with a StreamVane vane pack that accurately outputs a combined total pressure and swirl distortion profile at a defined distance downstream. In addition to the highly accurate combined distortion profile, ScreenVanes are unique in that they can operate under a wide range of inlet Mach numbers depending on the vane pack/screen design. Operating ranges for StreamVanes without a pressure screen are limited to the critical inlet Mach number to avoid transonic flow within the vane passages. However, it is desirable to increase this upper limit and broaden the range of transonic turbofan applications in which StreamVanes can operate.

In turn, a research effort was developed to investigate and analyze methods to improve throughflow and increase critical Mach numbers within StreamVane devices. The first step was to perform high fidelity, compressible, computational fluid dynamics (CFD) on previous fundamental designs such as the paired (twin) swirl and two-paired (quad) swirl StreamVanes. These simulations identified geometric features and vane parameters that corresponded to peak Mach numbers within both devices. Based on the CFD findings, a thorough literature review was conducted and consisted of methods to increase critical Mach numbers within vane passages. The literature was split into three separate parts: 1) Two-dimensional designs such as high-speed airfoil sections and cascade parameters, 2) three-dimensional designs such as blade lean and sweep, and 3) advanced designs such as tandem vanes, trailing and leading edge modifications, and endwall contouring. From this review, it was found that implementing blade lean and sweep into high-speed vane passages (favorable pressure gradients) was currently the most feasible and effective design strategy for increasing critical Mach numbers. In the last step of the effort, simplified StreamVane models containing bulk swirl vane packs were designed to evaluate the effect of both methods using a compressible, steady-state, Reynolds-averaged Navier-Stokes (RANS) CFD code. A baseline model was designed with standard design practices (no lean or sweep) for direct comparison. These comparisons include, but are not limited to, the critical Mach number, swirl distortion profile, and static structural properties performed by finite element analysis (FEA). These simulations are currently in progress.

In the proposed Turbo Expo paper, an introductory section will be provided which will overview the ScreenVane system, other distortion systems and their limitations, and motivation for the current research. This will be followed by a detailed description of the literature review, mainly consisting of two- and three-dimensional design techniques to increase critical Mach numbers (parts 1 and 2). A methodology section will then be provided and outline the implementation strategies, StreamVane designs, and computational tools/methods that were used for analysis (will include a grid independence study). The results section will present the predicted data and provide comparisons to the baseline design. Lastly, a conclusion section will summarize the effort, give recommendations, and list future work opportunities such as applications to other StreamVane devices and experimental validation. The work presented in the proposed paper condenses high throughflow design techniques, implementation strategies, and CFD analyses into a single publication that would be beneficial to the turbomachinery community.

Presenting Author: Andrew P. Hayden Virginia Tech

Presenting Author Biography: Andrew Hayden is a PhD student within the Department of Mechanical Engineering at Virginia Tech, where he conducts research on ScreenVane inlet distortion devices for partners in industry, government, and academia. During the year 2021, Andrew received a Master of Science degree in Engineering Mechanics in which his thesis work focused on computational methods to evaluate fluid structure interactions within the vane packs of StreamVanes. Currently, he is the project manager of a joint research effort between Virginia Tech and the Air Force Research Lab to advance and improve ScreenVane technology. Andrew also continues to characterize StreamVane vortex shedding using high fidelity CFD predictions and PIV measurements which will be the main focus of his dissertation work.

Authors:

Andrew P. Hayden Virginia Tech
John Gillespie Virginia Tech
Cole Hefner Virginia Tech
Alexandrina Untaroiu Virginia Tech
Todd Lowe Virginia Tech