Model-based analysis of boundary layer ingestion effect on lateral-directional aerodynamics using differentiated boundary conditions

2016 ◽  
Vol 231 (13) ◽  
pp. 2452-2463
Author(s):  
Jing Zhang ◽  
Xianfa Zeng ◽  
Lingyu Yang
Keyword(s):  
Boundary Layer ◽  
Boundary Conditions ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Propulsion System ◽  
Computational Method ◽  
Body Type ◽  
Detailed Model ◽  
Model Based ◽  
Distributed Propulsion

The noteworthy feature of aircraft with distributed propulsion configuration is the integration of a blended-wing-body type airframe and an embedded distributed propulsion system, thus inducing the specific boundary layer ingestion effect. Different boundary layer ingestion effects on the distributed engines may generate asymmetric flow fields on the airframe surface, and then lead to the unique lateral-directional aero-propulsive close coupling. To investigate the lateral-directional aerodynamics influenced by boundary layer ingestion, a new comprehensive computational method based on the differentiated boundary conditions is proposed. This method uses a synthetic three-dimensional computational model including the airframe and multi-engine to analyze the aerodynamic characteristics, and the essential boundary conditions can be extracted from the thermodynamic distributed propulsion system model to represent the different boundary layer ingestion intensities on the left and right engines. Subsequently, detailed model-based analyses of boundary layer ingestion influences on the lateral-directional aerodynamic characteristics are conducted, and the influence regularities under different flight states are revealed. All the results demonstrate that the differentiated boundary layer ingestion intensities on distributed engines can certainly affect the roll and yaw aerodynamic performance of the distributed propulsion configuration aircraft.

Aerodynamic benefits of boundary layer ingestion for distributed propulsion configuration

2019 ◽  
Vol 91 (10) ◽  
pp. 1285-1294 ◽  
Author(s):  
Jing Zhang ◽  
Wenwen Kang ◽  
Lingyu Yang
Keyword(s):  
Boundary Layer ◽  
Reference Value ◽  
Aerodynamic Characteristics ◽  
Comprehensive Analysis ◽  
Propulsion System ◽  
Analysis Method ◽  
Content Type ◽  
Model Based ◽  
Distributed Propulsion ◽  
Lift And Drag

Purpose Boundary layer ingestion (BLI) is one of the probable noteworthy features of distributed propulsion configuration (DPC). Because of BLI, strong coupling effects are generated between the aerodynamics and propulsion system of aircraft, leading to the specific lift and drag aerodynamic characteristics. This paper aims to propose a model-based comprehensive analysis method to investigate this unique aerodynamic. Design/methodology/approach To investigate this unique aerodynamics, a model-based comprehensive analysis method is proposed. This method uses a detailed mathematical model of the distributed propulsion system to provide the essential boundary conditions and guarantee the accuracy of calculation results. Then a synthetic three-dimensional computational model is developed to analyze the effects of BLI on the lift and drag aerodynamic characteristics. Findings Subsequently, detailed computational analyses are conducted at different flight states, and the regularities under various flight altitudes and velocities are revealed. Computational results demonstrate that BLI can improve the lift to drag ratio evidently and enable a great performance potentiality. Practical implications The general analysis method and useful regularities have reference value to DPC aircraft and other similar aircrafts. Originality/value This paper proposed a DPS model-based comprehensive analysis method of BLI benefit on aerodynamics for DPC aircraft, and the unique aerodynamics of this new configuration under various flight altitudes and velocities was revealed.

A Redesign Strategy to Improve the Efficiency of a 17-Stage Steam Turbine

2009 ◽  
Author(s):  
Filippo Rubechini ◽  
Andrea Schneider ◽  
Andrea Arnone ◽  
Stefano Cecchi ◽  
Francesco Malavasi
Keyword(s):  
Neural Network ◽  
Boundary Conditions ◽  
Steam Turbine ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Operating Conditions ◽  
Second Step ◽  
Geometrical Transformation ◽  
First Approximation ◽  
Original Reference

A three-dimensional RANS solver was applied to the aerodynamic redesigning of a 17-stage steam turbine. The redesign procedure was divided into three steps. In the first one, a single embedded stage was considered, and an optimization of stator lean and rotor twist was carried out by applying suitable repeating inlet/outlet boundary conditions. In the second step, a proper geometrical transformation between the original reference stage and the optimized one was identified and then applied to all other turbine stages, thus leading to a first approximation of the redesigned turbine. Finally, a neural-network-based refinement of the stator and rotor twist of each stage was performed to account for its actual position and operating conditions within the meridional channel. In this work, a detailed description of the redesign procedure is provided, and the aerodynamic characteristics of the optimized geometry are discussed and compared to the original ones.

Aerodynamically Induced Radial Forces in a Centrifugal Gas Compressor: Part 2—Computational Investigation

1999 ◽  
Vol 121 (4) ◽  
pp. 725-734 ◽  
Author(s):  
M. B. Flathers ◽  
G. E. Bache´
Keyword(s):  
Boundary Conditions ◽  
Three Dimensional ◽  
Computational Procedure ◽  
Computational Method ◽  
Experimental Methodology ◽  
Front Face ◽  
Radial Load ◽  
Vaneless Diffuser ◽  
Stage Performance ◽  
Computational Procedures

Radial loads and direction of a centrifugal gas compressor containing a high specific speed mixed flow impeller and a single tongue volute were determined both experimentally and computationally at both design and off-design conditions. The experimental methodology was developed in conjunction with a traditional ASME PTC-10 closed-loop test to determine radial load and direction. The experimental study is detailed in Part 1 of this paper (Moore and Flathers, 1998). The computational method employs a commercially available, fully three-dimensional viscous code to analyze the impeller and the volute interaction. An uncoupled scheme was initially used where the impeller and volute were analyzed as separate models using a common vaneless diffuser geometry. The two calculations were then repeated until the boundary conditions at a chosen location in the common vaneless diffuser were nearly the same. Subsequently, a coupled scheme was used where the entire stage geometry was analyzed in one calculation, thus eliminating the need for manual iteration of the two independent calculations. In addition to radial load and direction information, this computational procedure also provided aerodynamic stage performance. The effect of impeller front face and rear face cavities was also quantified. The paper will discuss computational procedures, including grid generation and boundary conditions, as well as comparisons of the various computational schemes to experiment. The results of this study will show the limitations and benefits of Computational Fluid Dynamics (CFD) for determination of radial load, direction, and aerodynamic stage performance.

A boundary-layer theory for plates with initial stress

1966 ◽  
Vol 62 (2) ◽  
pp. 313-327 ◽  
Author(s):  
N. Laws
Keyword(s):  
Boundary Layer ◽  
Boundary Conditions ◽  
Initial Stress ◽  
Elastic Deformation ◽  
Three Dimensional ◽  
Boundary Layer Theory ◽  
The State ◽  
Asymptotic Integration ◽  
Unstressed State ◽  
Small Deformations

AbstractA theory is presented for small deformations of a plate which is initially stressed, the state of initial stress not necessarily being obtained by elastic deformation from some other unstressed state. The method used is an asymptotic integration of the full three-dimensional equations. The usual Kirchhoff boundary conditions for stretching and bending are deduced from the analysis.

Thermal cycle analysis of turboelectric distributed propulsion system with boundary layer ingestion

2013 ◽  
Vol 27 (1) ◽  
pp. 163-170 ◽  
Author(s):  
Chengyuan Liu ◽  
Georgios Doulgeris ◽  
Panagiotis Laskaridis ◽  
Riti Singh
Keyword(s):  
Boundary Layer ◽  
Thermal Cycle ◽  
Propulsion System ◽  
Distributed Propulsion

Performance Analysis of a Distributed Propulsion System with Boundary Layer Ingestion

2015 ◽  
Author(s):  
Esteban A. Valencia ◽  
Chengyuan Liu ◽  
Laskaridis Panagiotis ◽  
Riti Singh ◽  
Devaiah Nalianda
Keyword(s):  
Boundary Layer ◽  
Performance Analysis ◽  
Propulsion System ◽  
Distributed Propulsion

Two New Flow Control Technologies Based on Vibration

2013 ◽  
Vol 774-776 ◽  
pp. 326-334
Author(s):  
Da Wei Li ◽  
Jin Hao Qiu ◽  
Rui Nie ◽  
Hong Li Ji
Keyword(s):  
Mach Number ◽  
Active Control ◽  
Lift Coefficient ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Computational Method ◽  
Control Effect ◽  
Active Deformation ◽  
Wing Model ◽  
Control Technologies

This paper aims at study the technology of flow active control to increase the wing lift and weaken the wing drag by using the method of fluid mechanics. There are two new active control methods proposed in this paper. In this article, the computational method is expanded to a three-dimensional wing model to verify the validity of the new active control technology. Research shows that the partial active deformation can improve the aerodynamic characteristics of airfoil by appropriate parameters optimize, moreover the effect of rotation was better. In the condition of low Mach number and rotational control, the lift coefficient can be increased 11%, the drag coefficient can be decreased 40%. The shock wave will move backward by control in the condition of high Mach number. The control effect of 3D model is not as good as 2D model.

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