The Virtual Manikin Project Andy Buxton Adrian Huggins & David Glynn

The “Virtual Manikin” ProjectThe “Virtual Manikin” Project

Andy Buxton

Adrian Huggins

&

David Glynn

The Defence Evaluation & Research Agency The Defence Evaluation & Research Agency The Defence Evaluation & Research Agency The Defence Evaluation & Research Agency

This work was carried out as part of Technology Group 5 (Human Sciences and Synthetic Environments) of the MoD Corporate Research Programme

DERA’s Ultimate Customers: DERA’s Ultimate Customers: the Front Linethe Front Line

Fundamentals of heat stressFundamentals of heat stress

Climate Clothing

Physical work

Experiment or Model?Experiment or Model?

Experimental methods– Laboratory or field based

Expensive Specific Possibly hazardous

Instrumented manikins for clothing Instrumented manikins for clothing evaluationevaluation

Thermal manikin– Thermal resistance (insulation)

‘Sweating’ manikin– Evaporative resistance

Virtual Manikin Project ObjectivesVirtual Manikin Project Objectives

Create a tool for modelling and assessing potentially

hazardous environments

Create a tool for assessing clothing systems prior to

construction

Reduce costs and time-scales for equipment

procurement

Geometry - STL file produced by laser Geometry - STL file produced by laser scanningscanning

Cartesian grid detailsCartesian grid details

Grid dimension– 38x52x56

Domain dimension– 2.5 x 2.0 x 1.9 m

Boundary Conditions & Source TermsBoundary Conditions & Source Terms

Open pressure boundary conditions at front, sides and top of domain

Inlet boundary condition specified at front for “forced convection” case

Initial and inlet temperatures 20oC Bouyancy forces represented

using Boussinesq model k-e turbulence model used Manikin heat source:

CO=1.E+5,VAL=34oC

Air movement and temperature contoursAir movement and temperature contours

Predicted manikin heat loss Predicted manikin heat loss

120

140

160

180

200

220

240

0 0.5 1 1.5 2

Air speed (ms-1)

Pre

dic

ted

hea

t lo

ss f

rom

man

ikin

(w

atts

)

Human thermo-physiological modelHuman thermo-physiological model

Information exchangeInformation exchange

Virtual Manikin-CFD model

calculates local boundary

conditions for physiological

model

Physiological model dictates

heat and mass (sweat)

sources for the CFD model

Virtual Manikin - CFD model

Thermo-physiological model

Information flowInformation flow

Flow calculation

Calculation of local boundary

conditions

2-D Thermal model

Calculation of segmental heat

and mass sources

Initial conditions

CFD model

Current PARSOL treatmentCurrent PARSOL treatment

PARSOL currently treats fluid flow differently from heat transfer (see figures)

Fluid - Solid interfaces are treated correctly as a “spline” for fluid flow and as a “staircase” for heat transfer

There can only be one fluid- solid interface in a given mesh cell

SOLID

FLUID

SOLID

FLUID

Extended PARSOL treatmentExtended PARSOL treatment

FluidFluid

SolidSolid

FluidFluid

Clothing simulationClothing simulation

The clothing model will require integration of a number of features in PHOENICS

– Moving objects– Stress-Strain– Fluid flow– Heat transfer

Pre-existing algorithms will be used for the deformation of clothing

Summary - 1Summary - 1

An STL file of a manikin was produced by laser scanning

This was imported into PHOENICS Flow simulations were produced and heat transfer

predictions made Further grid refinement is required A parallel cluster of PCs will be used for future work

Summary - 2Summary - 2

The CFD model will be linked to a human thermo-physiological model

More complex environments will be evaluated, e.g. vehicles, aircraft

PARSOL will be enhanced:-– Unify current treatment of Fluid Flow and Heat Transfer

– Extend PARSOL to allow multiple interfaces in any given cell

– The extended PARSOL feature will be available to all PHOENICS users

Points of contactPoints of contact

Andy Buxton, David Glynn,

Protection and Performance Department, Flowsolve Ltd.

Centre for Human Sciences, Arthur Road,

DERA, Ively Road, Wimbledon Park,

HANTS. GU14 OLX. Tel. +44 208 944 0940

United Kingdom Fax. +44 208 944 1218

Tel. +44 1252 393626 cfd@flowsolve.com

Fax +44 1252 392097

email: acbuxton@dera.gov.uk