Experimental results are presented on a method that eliminatesMach waves from the exhaust of supersonic jets and,hence, that removes a strong component of supersonic jet noise. Eliminationis achievedby surrounding the jet with an annular stream at prescribed velocity and temperature so that all turbulent motions become intrinsically subsonic. No mechanical suppressors are used. Implementation o...

The paper describes the results of numerical study of flow in the exhaust jet of turbofan engine CFM 56-3. Influence of computational domain decomposition, grid refinement and flow model on the jet flow field is discussed. Special attention is payed to simulation of nucleation and condensation processes in the exhaust jet. Growth of water clusters in the jet and cluster distribution in size are...

A new dynamic decoupling method is proposed for controlling complex uncertain systems. Where mathematical modeling is often tedious or inaccurate, the new method uses an unknown input observer (UIO) to estimate and cancel dynamic information in real time. Consequently, controller design and tuning become transparent as the number of required model parameters is reduced. A realistic turbofan sim...

To understand the behavior of a turbofan engine, one first needs to deal with the variety of data acquisition contexts. Each time a set of measurements is acquired, and such set may account for tens of parameters, the aircraft evolves in a specific flight mode. A diagnostic of the engine behavior models the observations and tests if anything appears as expected. A model of the engine measuremen...

Fan flow deflection for jet noise reduction was applied to subscale nozzles simulating the geometry and exhaust conditions of separate-flow turbofan engines. Two types of deflectors were tested, one comprising two pairs of vanes internal to the fan duct and the other consisting of a wedge positioned outside the fan duct. The noise reduction achieved by the vanes was strong in the downward direc...

We present a combined experimental and computational study of the dual-stream exhaust of a supersonic turbofan engine with noise-suppressing deflectors installed in the fan stream. The focus is on validating the computational code, extracting turbulent kinetic energy (TKE) trends, and connecting those trends to the measured noise reduction. We consider two operating conditions, a “cold” conditi...

The thermodynamics and acoustics of a fixed-cycle, bypass ratio 3 supersonic engine with an innovative noise suppression scheme is explored. The silencing method entails installation of variable turning vanes in the bypass exhaust of a separate-flow turbofan engine. During noise-sensitive segments of flight, the vanes impart a slight downward tilt to the bypass plume relative to the core plume,...

The thermodynamic cycle of an intercooled turbofan engine was optimized by considering various characteristics of intercoolers (ICs). Sixty-three intercooled turbofan engines were optimized using an evolutionary algorithm. Thirty-nine design parameters were analyzed using proper orthogonal decomposition, and the effects of the IC performance on the engine thermodynamic cycle were examined. The ...