Nusselt Optimization in Rectangular Ducts with...

Nusselt Optimization in

Rectangular Ducts with

Staggered Arrays of Short Pin

Fins Using STAR-CCM+ and

Optimate+

Ce document est la propriété de MBDA. Il ne peut être communiqué à des tiers et /ou reproduit sans l’autorisation préalable écrite de MBDA et son contenu ne peut être divulgué. © MBDA 2015.

This document and the information contained herein is proprietary information of MBDA and shall not be disclosed or reproduced without the prior authorization of MBDA. © MBDA 2015.

- Référence : Page :

Who is MBDA ?

• Created in 2001, MBDA is an industry leader and a

global player in the missile and missile systems sector

• With an unrivalled product portfolio covering the whole

range of land, maritime and airborne requirements

• Prime contractor with more than 45 missile system and

countermeasure programmes in operational service

• Extensive experience of delivering international

programmes including

Meteor, Storm Shadow/SCALP, Aster, Sea Venom,

Taurus

• Supported by three major shareholders:

Airbus Group, BAE Systems, Finmeccanica

M/TE/SM/AE/APL/TA 3306187-v1 14/01/20162




Who is MBDA ?

M/TE/SM/AE/APL/TA 3306187-v1 14/01/20163

• Three major multinational programme

families have allowed MBDA entry into

three key market sectors:

- Long-range air-to-air missiles

with the Meteor Programme

- Medium-range surface-to-air

systems with the Aster family

- Deep strike missiles with

Storm Shadow / SCALP and

Taurus

• These three families of programmes are

the core of MBDA’s activity now and in

the future




Use of STAR-CCM+

M/TE/SM/AE/APL/TA 3306187-v1 14/01/20164

• Thermal analysis team (projects support, multi-physics issues, skill development)

• Using CD-adapco software since 20 years

• Wide panel of multi-physics simulations including :

• Heat flux computation & Conjugate Heat Transfer (Compressive flow, high pressure / high

velocity, plume effect, …)

• , Eulerian-Eulerian, Eulerian-Lagrangian Multiphasic, Multispecies, VOF




METZGER validation

M/TE/SM/AE/APL/TA 3306187-v1 14/01/20165

• The METZGER experiment

• Subject

• STAR-CCM+® restitution of Metzger tests

(Metzger, Berry & Bronson Print - ASM

700/Vol104/Nov.1982)

• Modeling heat transfer in rectangular ducts with staggered

arrays of short pin fins.

• Experimental set up

• Air circulating around staggered arrays if short pin fins in

a 5mm high rectangular ducts

• 12 thermally independent arrays of copper blocks with

5mm high pin fins.

• 12 heaters to control cooper block temperature

Flow direction

12 copper blocks arrays with heaters up & down

Staggered arrays of pins fins




METZGER validation

M/TE/SM/AE/APL/TA 3306187-v1 14/01/20166

• Modeling description

• 3D steady

• Navier-Stokes + Energy equations

• k-ω turbulence modelling

• Fluid (Air) perfect gas

• Constant thermodynamic & transport properties at standard conditions

• Conjugate heat transfer fluid-solid, solid-solid (with thermal resistance)

• 3D thermal diffusion in the pins and the walls in Copper and in Kapton (Heaters)

• Imposed thermal power on the heaters

• Convective thermal loss on the external sides of the Up. & Low. Heaters

• Adiabatic walls on the Up. & Low. Cu sides elsewhere

• 2 symmetry planes




METZGER validation

M/TE/SM/AE/APL/TA 3306187-v1 14/01/20167

• Results example (Tair=300K ; Vref=30m/s ; Power = 2 x 15W per array)




METZGER validation

M/TE/SM/AE/APL/TA 3306187-v1 14/01/20168

• Results example (Tair=300K ; Vref=30m/s ; Power = 2 x 15W per array)




METZGER validation

M/TE/SM/AE/APL/TA 3306187-v1 14/01/20169

• METZGER validation

• For 2 experiments Reynolds numbers

• Comparison test-simulation on Nusselt numbers sections 2 to 11

• Good overlap for these two Reynolds numbers




MBDA & Design optimization

M/TE/SM/AE/APL/TA 3306187-v1 14/01/201610

• Potential value of design optimization

• Collaborative project with CD-adapco® to evaluate the feasibility of

doing design exploration using STAR-CCM+ and Optimate+TM

• On fluid loops using heat exchangers, optimization allows :

• The increasing of thermal exchanges

• The reducing of pressure drop, fluid mass flow, electrical power,

subsystem total mass, …

• In a general way, design exploration technics are motivating for :

• The management of thermal/mechanical/chemical stresses on pieces

• The optimization of trials

• The Improvement of equipment’s performances




Optimization Scope

• Pareto optimization of Metzger design

• Parameterize pin geometry from Metzger experiments

• Due to simple geometry STAR-CCM+ 3D-CAD modeler was used

• Identify Pareto front between pressure drop and Nusselt number

• Identify designs that have both lower pressure drop and higher average

Nusselt number

• Single objective optimization of novel pin design concept

• Design concept chosen to include a larger number of parameters

• Evaluate capability to include native CAD parameters in the optimization

workflow

• Select a problem statement that is representative of the kind of design

problems likely to be faced in a production environment

M/TE/SM/AE/APL/TA 3306187-v1 14/01/201611




Metzger Pareto Optimization

• Parameters (6)

• Number of stream wise

pins

• Number of transverse

pins

• Pin diameter

• Ratio of heat exchanger

occupied by pins

• Objectives

• Maximize heat

exchanger average Nu

• Average taken over

entire wetted surface

• Characteristic length

set to hydraulic

diameter

• Minimize pressure drop

M/TE/SM/AE/APL/TA 3306187-v1 14/01/201612





• 250 designs evaluated

M/TE/SM/AE/APL/TA 3306187-v1 14/01/2016

0

2

4

6

8

10

12

14

16

18

20

250 300 350 400 450 500

Pre

ssu

re D

rop

(kP

a)

Average Nusselt Number

All Designs

Baseline

Better Than Baseline

13





• Possible 2.7% increase in

average Nu for no additional

pressure drop

• Possible 27% reduction in

pressure drop for no loss in

average Nu

M/TE/SM/AE/APL/TA 3306187-v1 14/01/2016

Metzger Exp. Highest Average Nu

Lowest Pressure Drop

14




Metzger Pareto Optimization - Conclusions

• Pareto front between pressure drop and average Nu identified

• Identified designs with improvement in either objective

without degradation in the other, particularly effective at

reducing pressure drop

• Room for additional resolution of the Pareto front near the

Metzger design

• Average Nu may not best represent the heat transfer objective

of an industrial design problem

• Apply constraints to objectives in order to focus Pareto

optimization

• STAR-CCM+ optimization was robust and efficient with 3D-

CAD

M/TE/SM/AE/APL/TA 3306187-v1 14/01/201615




Novel Pin Design Optimization – Design Concept

M/TE/SM/AE/APL/TA 3306187-v1 14/01/2016

• Parameters (11)

• Number of stream wise

pins

• Number of transverse pins

• Pin length

• Pin width

• Pin height

• Pin angle

• Pin fillets (top, sides,

bottom)

• Pin draft angle

• Heater power output

• Design Considerations

• Heater max temp < 85 C

• Minimize pressure drop

• Maximize heater output

16




Novel Pin Design Optimization – Background and Methodology

• CATIA V5 used to generate

parametric model

• Mesh

• 1.3 ~ 4.0 M polyhedral cells

• Physics

• Metzger experiments

• Reporting

• 750 iteration moving averages of

pressure drop and max

temperature

• Convergence

• 30 Pa 750 iteration asymptotic

stopping criteria for pressure

drop

• 12000 max iterations

• flags design as error due to lack

of convergence if reached

M/TE/SM/AE/APL/TA 3306187-v1 14/01/201617




• sdfds

Novel Pin Design Optimization - Results

M/TE/SM/AE/APL/TA 3306187-v1 14/01/201618




Novel Pin Design Optimization - Results

M/TE/SM/AE/APL/TA 3306187-v1 14/01/2016

All Designs < 86.5 C < 85.25 C Best Design

Temp Pressure Angle Draft Height Nx Ny Length Fillet Radii Width

19




Novel Pin Design Optimization – Results and Future Work

• Successfully incorporated native CAD parameters into an

Optimate+ workflow

• Total study turn around time was < 2 weeks

• Heater max temp yielded results that more closely matched

common design goals than average Nu

• Optimate+ obtained design meeting max temperature

constraint

• Expect continued improvements in pressure drop with

additional runs

• Potential improvements to the geometry

• Increase robustness of CAD parameters (~25% failure rate observed)

• Allow rows of pins to be staggered similar to the Metzger geometry

M/TE/SM/AE/APL/TA 3306187-v1 14/01/201620

Nusselt Optimization in Rectangular Ducts with...

Documents

Transcript of Nusselt Optimization in Rectangular Ducts with...