Development and evaluation of new bleed boundary condition models for supersonic inlet boundary layer bleed flow

Akar, Gökhan
Shock wave/boundary layer interaction is an important issue that should be considered when studying supersonic inlet design for air vehicles. Porous bleed systems have traditionally been used for increase stability and efficiency of the supersonic inlets by means of removing the lower momentum part of the boundary layer to prevent flow separation caused by adverse pressure gradient. However, evaluating and determining the effect of the boundary layer bleed system on the performance of the supersonic inlet is one of the most challenging problems. In this thesis, single and porous bleed systems are studied for validation and investigation of bleed boundary condition modeling with concentrating on normal bleed hole configuration in computational fluid dynamics (CFD). Firstly, for validation of the method, three-dimensional CFD simulations are performed on fully resolved models (FRM) with modeling bleed plenum and hole cavity details. Grid converge study is conducted on different levels of grids using Spalart-Allmaras, Realizable k-ε and SST k-ω turbulence models. Optimal grid resolution and turbulence model are determined for bleed simulations. CFD analyses are expanded for different plenum total pressure ratios (Ppl/Pt). As a result of validation studies, the CFD results show good agreement with the wind tunnel test data. Furthermore, three new bleed boundary condition models are introduced to simulate bleed flow without modeling the bleed plenum and cavity details of the holes. Additional CFD analyses on the porous bleed case are performed including blowing effects to examine the correlation between mass flow rate and flow properties at the reference boundaries. Collected data are presented and discussed according to scaled parameters. The best curve fitting models on the scaled parameters are selected for each new bleed boundary condition (BBC) model. In order to evaluate the validity of BBC modeling alternatives, CFD studies are performed on the porous bleed systems with and without shock interaction with the implementation of new BBC models to the solver. Consequently, the results of the new BBC models are compared with the test data and the results of the FRM simulations. The bleed model based bleed region flow properties predicts bleed flow rates very close to the reference data. Moreover, all three models achieve remarkable success on simulation of flow structure and the models reflect well the impacts of the bleed region on efficiency in terms of total pressure recovery.


Validation of MISES 2 D Boundary Layer Code for High Pressure Turbine Aerodynamic Design
ANDREW, PHILIP; Kahveci, Harika Senem (2007-01-01)
Avoiding aerodynamic separation and excessive shock losses in gas turbine turbomachinery components can reduce fuel usage, and thus reduce operating cost. In order to achieve this, blading designs should be made robust to a wide range of operating conditions. Consequently, a design tool is needed which can be executed quickly for each of many operating conditions, and on each of several design sections which will accurately capture loss, turning and loading. This paper presents the validation of a boundary ...
Design and analysis of a vertical axis water turbine for river applications using computational fluid dynamics
Demircan, Eren; Aksel, Mehmet Haluk; Pınarcıoğlu, Mehmet Melih; Department of Mechanical Engineering (2014)
The main purpose of this study is to design a Darrieus rotor type vertical axis water turbine using Computational Fluid Dynamics (CFD) in order to be used in river currents. The CFD modeling is based on two dimensional numerical solution of the rotor motion using commercial Unsteady Reynolds Averaged Navier-Stokes solvers, Ansys Fluent and CFX. To validate the two dimensional numerical solution, an experimental Darrieus rotor type water turbine from literature is studied and performance of several turbulenc...
Development of Structural Neural Network Design Tool for Buckling Behaviour of Skin-Stringer Structures Under Combined Compression and Shear Loading
Okul, Aydın; Gürses, Ercan (2018-11-15)
Stiffened panels are commonly used in aircraft structures in order to resist high compression and shear forces with minimum total weight. Minimization of the weight is obtained by combining the optimum design parameters. The panel length, the stringer spacing, the skin thickness, the stringer section type and the stringer dimensions are some of the critical parameters which affect the global buckling allowable of the stiffened panel. The aim of this study is to develop a design tool and carry out a geometri...
Development of view factor correlations for modeling thermal radiation in solid particle solar receivers using CFD-DEM
Johnson, Evan; Baker, Derek Keıth; Tarı, İlker (null; 2018-10-05)
Radiation heat transfer must be modeled when designing any high temperature solid particle solar receiver or particle-fluid heat exchanger, but computationally efficient radiation models are not currently available in coupled Computational Fluid Dynamics - Discrete Element Method (CFD-DEM) codes, which is the focus of this work. Monte Carlo ray tracing simulations were run to find view factors between particles in packed beds, and correlations were found to estimate both particle-particle and particle-wall ...
Experimental analysis on the measurement of ballistic properties of solid propellants
Cuerdaneli, S.; Ak, M. A.; Ulaş, Abdullah (2007-06-16)
Ballistic properties of solid propellants play an important role in the performance of the solid propellant rocket motors. Therefore, ballistic properties of a likely propellant should be known and provided to the design engineers. In this study, a specific AP/HTPB composite solid propellant (SCP) was examined to obtain steady-state linear burning rates as a function of pressure and propellant initial temperature, temperature sensitivity, and pressure deflagration limit (PDL). In some tests micro-thermocoup...
Citation Formats
G. Akar, “Development and evaluation of new bleed boundary condition models for supersonic inlet boundary layer bleed flow,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Aerospace Engineering., Middle East Technical University, 2019.