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Multidisciplinary Optimization of Air breathing Hypersonic Vehicles

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					Problem 5

Classification: I A 3

Title: Multidisciplinary optimization of Air breathing Hypersonic Vehicles

References: Kevin G. Bowcutt, The Boeing Company, Long Beach, California 90807-5309,

Journal of Power and Propulsion Vol. 17, No. 6, November–December 2001.

Description:

This problem deals with maximizing the range of a hypersonic cruise missile wherein there

is a high degree of interdependency between the airframe and the engine. This problem

deals with development and implementation of MDO in the conceptual design of a

hypersonic Air breathing Vehicle which combines propulsion and external aerodynamic

forces, mass properties and internal volumetric modeling in maximizing the range of the

vehicle.


System Representation:

                                       Geometric Model



                                     Stability and Control
                                             Model


  Optimizer
                                    Mass Properties Model


                                   Trajectory/Performance
                                           Model



                                      Objective Function
DSM MATRIX:



     Geometric
     Analysis


                    Stability and
                    Control Analysis


                                       Mass Properties
                                       Analysis



                                                         Trajectory
                                                         Analysis




Design variables:



D = drag
g = gravitational acceleration

Isp = specific impulse

Iyy = pitch moment of inertia

K = centrifugal relief factor

L = lift

L p = propulsive lift

lchine = chine length

lcowl = nozzle cowl length

M® = pitching-moment derivative

P q = pitch acceleration

R = range

rE = Earth’s radius

T = thrust in flight direction

TQ = thrust magnitude

T2 = time to double

V = velocity

W = weight

W0 = weight modified by centrifugal relief

WQ = required cruise aerodynamic lift

wf = fuel flow rate

xeng = engine axial location

® = angle of attack

μcant = engine cant angle
μnose = upper-body nose angle

μT = thrust vector angle



Objective Function:

Maximize: R(range)




Constraints:

      L=W

      T=D(Thrust equal to drag during cruise)

      Height ≤ Heightmax

      Width ≤ Widthmax

      Length ≤ Lengthmax

				
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