The ScreenVane Family of Inlet Distortion Generators for Ground Based Testing of Fans, Compressors and Engines

Due to requirements to minimize radar cross-sections, most modern turbine engines of military aircraft are coupled with offset diffusers that create significant fan face distortion. Conceptual blended-wing/body commercial aircraft also create distortion challenges. In order to fully understand the effects of complex inlet distortions on conventional fan and compressor designs, a range of inlet distortions needs to be processed through the compression system and evaluated for performance impacts. The ScreenVaneTM family of distortion generators provides the necessary testing capability. The technology has been under development at Virginia Tech for nearly 10 years and has advanced to a high TRL. However, acceptance for ground-based engine testing has been limited. To address this issue, Virginia Tech has teamed with Techsburg, Inc. to better commercialize the product. Through their joint STTR Phase I effort, the team identified structural integrity as the primary hurdle to broader acceptance of the technology and quality of the resulting distortion pattern as the second issue. The objective of the proposed Phase II effort is to address both matters. Despite being design to high static factors of safety, analysis of previous test results showed that high-risk applications could lead to failure through flutter. To avoid this potential problem, the Phase II effort aims to develop a safety criteria for preventing flutter, analysis methods to evaluate the criteria and designs methods to insure the criteria is met. The biggest remaining challenge in designing accurate distortion patterns is the impact of structural support screens required for mounting distortion generating screens of ScreenVanesTM. These so called “backer screens” interact with the lower porosity profile-producing screens resulting in a composite loss distribution that remains inadequately modeled. The design system will be extended to accommodate many commonly used backer screen configurations by acquiring experimental data on a range of porosities in combination with the existing portfolio of lower porosity screens, thus, addressing most customers’ needs empirically.