Methods and apparatus to model thermal mixing for prediction of multi-stream flows

Patent metadata

Field	Value
Publication number	US-10366182-B2
Application number	US-201514806373-A
Country	US
Kind code	B2
Filing date	Jul 22, 2015
Priority date	Jul 22, 2015
Publication date	Jul 30, 2019
Grant date	Jul 30, 2019

Abstract

Methods and apparatus to model thermal mixing for prediction of multi-stream flows are described. An example method includes determining characteristics of a nozzle of an aircraft; estimating momentum diffusion due to turbulence associated with the nozzle based on the determined characteristics; and estimating thermal diffusion due to the turbulence associated with the nozzle based on the estimated momentum diffusion, wherein the estimating of the thermal diffusion due to the turbulence is based on a spatially varying turbulent Prandtl number.

First claim

What is claimed is:

1. A method, comprising:
receiving, at a processor, characteristics of a nozzle of an aircraft to be tested, the characteristics input by a person via an interface, the characteristics including a shape of the nozzle;
generating, via the processor, a domain representation of the nozzle based on the characteristics of the nozzle, the domain representation divided into a plurality of cells;
estimating, via the processor, momentum diffusion due to turbulence associated with the nozzle based on the determined characteristics;
estimating, via the processor, thermal diffusion due to the turbulence associated with the nozzle based on the estimated momentum diffusion and a spatially varying turbulent Prandtl number, wherein the spatially varying turbulent Prandtl number is calculated using the equation

Pr
τ

=

μ
τ

⁢



∇
T



2



ρ
⁢

⁢

u
j
′

⁢

T
′

_

·

∇
j

⁢
T



,

 wherein μ τ is turbulent viscosity, T is static temperature, ρ is density, and u′ j T′ is a turbulent heat flux vector, and wherein the turbulent heat flux vector is calculated using the equations

ρ
⁢

⁢

u
j
′

⁢

T
′

_

*

=

k
/
ɛ

c

1
⁢

⁢
θ

+

1
2

⁢

(

P
k

ɛ

-
1

)

⁢

(

ρτ
jm

⁢

∂
T

∂

x
m

-

(

1
-

c

2
⁢

⁢
θ

)

⁢
ρ
⁢

⁢

u
m
′

⁢

T
′

_

(

N
-
1

)

⁢

∂

u
j

∂

x
m

-

c

1
⁢
θ

,
w

⁡

(

ρ
⁢

Assignees

• Boeing Co

Inventors

• Mani Mortaza
• Moffitt Nicholas J
• Dorgan Andrew James

Classifications

• G06F30/20 Primary

  Design optimisation, verification or simulation (optimisation, verification or simulation of circuit designs G06F30/30) · CPC title

• G06F17/11 Primary

  for solving equations {, e.g. nonlinear equations, general mathematical optimization problems (optimization specially adapted for a specific administrative, business or logistic context G06Q10/04)} · CPC title

• G06F2119/08

  Thermal analysis or thermal optimisation · CPC title

• G06F30/15

  Vehicle, aircraft or watercraft design · CPC title

• G06F2111/10

  Numerical modelling · CPC title