Requirements and Advances in Simulating Aircraft Inlet Total Pressure Distortion in Turbine Engine Ground Tests

Abstract

The development of high-performance aircraft demands the successful integration of the airframe, engine, and control systems. Advancements in aircraft technologies bring with them the need to improve the computational and experimental tools applied to the airframe-engine compatibility evaluations. This paper focuses on the need to improve one of these tools, the direct-connect turbine engine test method. In particular, the paper advocates improving the direct-connect test simulation of the total-pressure distortion induced in flight by the external airframe and the inlet system. To meet the needs of future direct-connect tests, AEDC embarked on the development of a transient total-pressure distortion generator. The paper first introduces specific total pressure pattern simulation requirements that form the basis for the development and results of the distortion generator development process. Included are sample distortion generator concept test results and a description of a fully functional prototype that is in fabrication. Next, the paper summarizes a parallel development of computational fluid dynamics (CFD) tools that will be applied to adapting the prototype design to specific test facilities and to the operation of the distortion generator in turbine engine tests. The paper concludes with a look ahead from the total-pressure distortion methodology to test and computational methodologies for other parameters, with emphasis on swirl.

Flow Distortion Into the Core Engine for an Installed Variable Pitch Fan in Reverse Thrust Mode

“…A preliminary guideline of CDI and RDI threshold values to define a safe limit for stable compressor operation can be estimated from the reported loss in surge pressure ratio for compressors responding to a number of standard circumferential and radial distorted inlet flows. With the consideration that a loss in surge pressure ratio of <5% would be a typical acceptable limit for safe operation, the threshold CDI and RDI values are estimated as 0.07 [9][10][11][12][13][14][15][16][17].…”

Experimental Investigation of Inlet Distortion Effect on Performance of a Micro Gas Turbine

“…It is named after the direct connection between the turbine engine and the air supply duct. Reference [17][18] contains a well-made description of direct-connect test method.…”

“…More advanced techniques usually utilize some variable geometries that can produce different distortion patterns using flexible configurations. A description on some of these techniques and their relevant test setups can be found in [17][18].…”

Equivalent simulation method for total pressure distortion of ship inlet

“…Regarding the simulation of total pressure distortion, scholars have conducted extensive research in the field of testing and simulation. Since the 1960s, organizations such as AEDC and NASA in the United States have developed devices such as distortion screens (Bobula, 1979), plane wave method (Kutschenreuter et al, 1973), random frequency distortion generators, and air jet distortion simulation generators to achieve distortion simulation (Braithwaite et al, 1970;Meyer et al, 1970;Overall and Harper, 1974;Hubble and Smith, 1979;Mcllveen, 1979;Beale et al, 2002;Beale et al, 2006;Beale et al, 2007) and others have introduced research on transient total pressure distortion simulation technology and proposed concepts such as total temperature distortion simulation devices and eddy current distortion simulation devices based on the characteristics of various simulation devices. Zhang et al (2017) designed a crescentshaped pressure distortion simulator with a continuously adjustable distortion index achieved by increasing the curvature of the plugboard.…”