Computational Fluid Dynamics Modeling of a Supersonic Nozzle and Integration into a Variable Cycle Engine Model

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

Connolly²,

Seiel³

2014

Self Cite

A summary of the propulsion system modeling under NASA's High Speed Project (HSP) AeroPropulsoServoElasticity (APSE) task is provided with a focus on the propulsion system for the lowboom supersonic configuration developed by Lockheed Martin and referred to as the N+2 configuration. This summary includes details on the effort to date to develop computational models for the various propulsion system components. The objective of this paper is to summarize the model development effort in this task, while providing more detail in the modeling areas that have not been previously published. The purpose of the propulsion system modeling and the overall APSE effort is to develop an integrated dynamic vehicle model to conduct appropriate unsteady analysis of supersonic vehicle performance. This integrated APSE system model concept includes the propulsion system model, and the vehicle structural-aerodynamics model. The development to date of such a preliminary integrated model will also be summarized in this report. IntroductionHE slender configuration of low-boom aircraft, combined with rigid body effects and non-linear aerodynamics, often results in highly complex nonlinear aeroelastic/flight dynamics phenomena. Combined with the propulsion system, the AeroServoElastic ASE/APSE dynamic coupling phenomena and the resulting structural oscillations can affect the ride quality, and the vehicle flight dynamics and control. The APSE dynamic effects can simultaneously influence the airframe and propulsion system controls to produce undesirable effects on performance and flying characteristics. Thus, these APSE phenomena need to be thoroughly understood for supersonic flight to be safe, efficient and comfortable. Understanding these phenomena through the modeling capabilities that are being developed will provide the opportunity to use active controls to mitigate these undesirable effects in order to improve performance such as ride quality, vehicle stability, and flight efficiency. This new research will enhance the analysis and design capabilities for slender supersonic aircraft.A top priority for the High Speed Project ASE task is to develop the tools required to perform accurate, high fidelity Aeroelastic (AE), ASE, and APSE analyses in support of the design of future low-boom supersonic civil aircraft. As a means of accomplishing that priority, the NASA HSP is working with Lockheed Martin to develop vehicle concepts and analyze the performance of these vehicles. Under the NASA N+2 (2 generations from present state) design, Lockheed Martin has developed a low-boom supersonic configuration as shown in Fig. 1.A vast knowledge base of analytical, computational, wind tunnel and flight data exists on the ASE subsonic vehicles and supersonic fighter aircraft, but considerably less data are available in this area for supersonic cruise configurations. Reference 1 describes the developments to date in ASE that are also utilized for this overall APSE effort. For propulsion system dynamics modeling and testing, there is not much releva...

Section: Nozzle Modelmentioning

confidence: 97%

“…15 (simulation results specifically covering the latest VCE update can be found in Ref. 15). This figure shows the APSE closed-loop wing velocity in the vicinity of the inlet compared to wing velocity with the ASE alone (i.e., without thrust variation forces impacting the wing).…”

Section: Integrated Apse Modelmentioning

confidence: 99%

Propulsion System Dynamic Modeling of the NASA Supersonic Concept Vehicle for AeroPropulsoServoElasticity

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

Connolly²,

Seiel³

2014

Self Cite

“…28 As previously mentioned, the VCE propulsion system has three nozzles. All of the nozzles are modeled exactly the same with different geometries.…”

Section: Nozzle Modelingmentioning

confidence: 98%

Nonlinear Dynamic Modeling of a Supersonic Commerical Transport Turbo-Machinery Propulsion System for Aero-Propulso-Servo-Elasticity Reserach

Connolly

Carlson

51st AIAA/SAE/ASEE Joint Propulsion Conference

et al. 2015

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This paper covers the development of an integrated nonlinear dynamic model for a variable cycle turbofan engine, supersonic inlet, and convergent-divergent nozzle that can be integrated with an aeroelastic vehicle model to create an overall Aero-Propulso-ServoElastic (APSE) modeling tool. The primary focus of this study is to provide a means to capture relevant thrust dynamics of a full supersonic propulsion system by using relatively simple quasi-one dimensional computational fluid dynamics (CFD) methods that will allow for accurate control algorithm development and capture the key aspects of the thrust to feed into an APSE model. Previously, propulsion system component models have been developed and are used for this study of the fully integrated propulsion system. An overview of the methodology is presented for the modeling of each propulsion component, with a focus on its associated coupling for the overall model. To conduct APSE studies the described dynamic propulsion system model is integrated into a high fidelity CFD model of the full vehicle capable of conducting aero-elastic studies. Dynamic thrust analysis for the quasi-one dimensional dynamic propulsion system model is presented along with an initial three dimensional flow field model of the engine integrated into a supersonic commercial transport. NomenclatureA Cross-sectional area N Engine rotational speed M Mach number P Pressure P R Pressure Ratio T Temperature V Volumė m Mass flow t Time x Length η Efficiency γ Ratio of specific heat ρ Density Subscripts c Engine characteristic parameter n Engine component location s Static flow condition t

“…The addition of the VGV model to the original volume dynamics model, 2 which is also incorporated in this stage-by-stage model, is described in more detail in Ref. [9] for the compressor maps, and in Ref. [2] for the VGV effective area calculations.…”

Section: B Initial Scalingmentioning

confidence: 99%

Stage-by-Stage and Parallel Flow Path Compressor Modeling for a Variable Cycle Engine

51st AIAA/SAE/ASEE Joint Propulsion Conference

Connolly²,

Cheng

2015

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This paper covers the development of stage-by-stage and parallel flow path compressor modeling approaches for a Variable Cycle Engine. The stage-by-stage compressor modeling approach is an extension of a technique for lumped volume dynamics and performance characteristic modeling. It was developed to improve the accuracy of axial compressor dynamics over lumped volume dynamics modeling. The stage-by-stage compressor model presented here is formulated into a parallel flow path model that includes both axial and rotational dynamics. This is done to enable the study of compressor and propulsion system dynamic performance under flow distortion conditions. The approaches utilized here are generic and should be applicable for the modeling of any axial flow compressor design.