A Flight Simulation Vision for Aeropropulsion Altitude Ground Test Facilities

Abstract

Testing of a gas turbine engine for aircraft propulsion applications may be conducted in the actual aircraft or in a ground-test environment. Ground test facilities simulate flight conditions by providing airflow at pressures and temperatures experienced during flight. Flight-testing of the full aircraft system provides the best means of obtaining the exact environment that the propulsion system must operate in but must deal with limitations in the amount and type of instrumentation that can be put on-board the aircraft. Due to this limitation, engine performance may not be fully characterized. On the other hand, ground-test simulation provides the ability to enhance the instrumentation set such that engine performance can be fully quantified. However, the current ground-test methodology only simulates the flight environment thus placing limitations on obtaining system performance in the real environment. Generally, a combination of ground and flight tests is necessary to quantify the propulsion system performance over the entire envelop of aircraft operation. To alleviate some of the dependence on flight-testing to obtain engine performance during maneuvers or transients that are not currently done during ground testing, a planned enhancement to ground-test facilities was investigated and reported in this paper that will allow certain categories of flight maneuvers to be conducted. Ground-test facility performance is simulated via a numerical model that duplicates the current facility capabilities and with proper modifications represents planned improvements that allow certain aircraft maneuvers. The vision presented in this paper includes using an aircraft simulator that uses pilot inputs to maneuver the aircraft engine. The aircraft simulator then drives the facility to provide the correct engine environmental conditions represented by the flight maneuver.

Asymmetric Flow Phenomena Affecting the Characterization of the Control Plant of an Altitude Test Facility for Aircraft Engines

“…Simulations published by Montgomery et al at the Arnold Engineering Development Center (AEDC) are based on quasi steady-state, one-dimensional models due to computational, feasibility, and resource constraints [13][14][15][16][17]. The benefits are to verify the functionality of new software and hardware, perform dry runs before a test campaign to avoid errors, and provide operator training for failures in a safe environment at low costs.…”

Performance Evaluation of Second-Throat Diffuser for High-Altitude-Test Facility

“…= second-throat diameter D 3 = diffuser exit diameter e = specific internal energy G v = rate of production of turbulent viscosity k = thermal conductivity L = length in axial direction L 1 = entry duct length L 2 = convergent duct length L 3 = second-throat length L 4 = D IFFUSERS find application in many fluid systems such as aircraft, gas turbines, ramjets, wind tunnels, high-altitude-test facilities, and jet pumps [1][2][3] for converting the flow kinetic energy into static-pressure rise. Supersonic ejector-diffusers with a second throat are employed in the testing of large-expansion-ratio rocket motors in high-altitude-test (HAT) facilities to recover pressure from a low-vacuum condition to the atmospheric value.…”