SAFE Symposium London March 2010 Stewart Gregory Survitec Group - - PowerPoint PPT Presentation

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SAFE Symposium London March 2010 Stewart Gregory Survitec Group - - PowerPoint PPT Presentation

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Meeting the Thermal Burden Needs of Todays Aircrew in Any Given Scenario SAFE Symposium London March 2010 Stewart Gregory Survitec Group Overview Problem Statement Approach to the Solution Design Drivers Comfort &

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SLIDE 1

“Meeting the Thermal Burden Needs of Today’s Aircrew in Any Given Scenario”

SAFE Symposium London March 2010

Stewart Gregory Survitec Group

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SLIDE 2

Overview

  • Problem Statement
  • Approach to the Solution
  • Design Drivers
  • Comfort & Mobility
  • Sizing & Fit
  • Fully Integrated Design
  • Integrity
  • Manufacturability
  • Performance
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SLIDE 3

The Problem

Rectal Temperature (without LCG) 36.5 36.7 36.9 37.1 37.3 37.5 37.7 37.9 38.1 38.3 38.5 38.7 20 40 60 80 100 120 140 160 180 200 220 240

Time (min) Rectal Temperature (

  • C)

Rectal Temperature (without LCG)

Heart Rate (Without LCG) 40 50 60 70 80 90 100 110 120 130 20 40 60 Time (min) Heart Rate (beats.min

  • 1)

Heart Rate (Without LCG)

Donning & Baseline measurement Exercise & Trial Rest Period

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SLIDE 4

The Problem: Thermal Stress – Limiting Performance

  • Consequences of Thermal Stress:
  • Fatigue (increased heart rate, oxygen uptake)
  • Dehydration
  • Impaired Concentration
  • Ultimately reduces human performance and endurance
  • RFDB Solution → circulate cooled liquid

around the body to extract heat and mitigate the onset of thermal stress

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SLIDE 5

The Solution - Where do we begin?

  • Understanding the User’s Needs:
  • Local Environment
  • Mission Roles
  • Ambient Conditions
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SLIDE 6

Design Drivers

  • Comfort & Mobility
  • Sizing & Fit
  • Fully Integrated Design
  • Integrity
  • Manufacturability
  • Performance
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SLIDE 7

Comfort & Mobility

  • Maximising Endurance & Mission

Effectiveness

…“ comfortable pilot is an effective pilot!”…

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SLIDE 8

Fully Integrated Design

  • Summer Land
  • Winter Land
  • Winter Sea
  • Chem Bio
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SLIDE 9

FEATURE BENEFIT

  • Ergonomic Tabard Design
  • Ease of Donning & Doffing
  • Adjustment for fit
  • Reduced wear on garment
  • Minimal size range
  • Moisture Transfer System
  • Comfort
  • Minimises ‘chill effect’
  • Encourages natural body cooling
  • Manifold & Network Tubing
  • Maximise heat transfer
  • Minimise pressure drop
  • Comfort (thermal sensation)
  • Materials Selection
  • Comfort and weight
  • Durability
  • Laundering (300 cycles)

LCV Design Summary

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SLIDE 10

Performance

  • Fast Jet Thermal Burden Human Physiology Trials
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SLIDE 11

Performance – Thermal Burden Human Physiology Trials

  • Specification Requirements

– Maintain body core temperature at or below 38.0 C (100.4F) – Environment conditions: 1% hot day

  • Ambient = 48.8 C (120 F)
  • Relative Humidity = 20%
  • Solar Load = 1120 W.m-2
  • Withdrawal Criteria

– A trial was terminated if:

  • Rectal temperature exceeded 38.5 C (101.4 F)
  • Heart rate exceeded 165 beats per minute
  • The subject wished to be removed from the thermal

chamber

  • The Supervising Medical Officer or the Principal

Investigator, or a member of the Study Team thought it advisable to remove him

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SLIDE 12

Pre-Test Preparation

Ambient: Room Temperature 20 C, Air speed 0.5 m.s-1

  • 1 male subject instrumented
  • Subject sat for 30 minutes at rest
  • LCV coolant set-up: Tyfoxit F50, Flow Rate 1.0 l.min-1, Inlet Temperature 18 C

Test Procedure (Worst Case Scenario)

Ambient: Dry-bulb Temperature 48.8 C, RH 20%, Air speed 0.5 m.s-1

  • Subject entered chamber and donned AEA ensemble (Winter/Sea or Summer/Land or

Winter/Sea with Chem. Bio & respirator)

  • Subject walked 50 metres on treadmill (LCV connected), ascended & descended 3 steps
  • f a ladder (simulating aircrew ground operations)
  • Subject strapped into ejection seat and remained at rest for a period of 15 minutes (LCV

disconnected) (simulating cockpit purging)

  • Subject executed 60 minute exercise regime (LCV connected) by means of a leg

ergometer (simulating fast jet cockpit workload ~ 100 W.m-2)

  • Subject walked 50 metres on treadmill (LCV connected), ascended & descended 3 steps
  • f a ladder (simulating aircrew ground operations)
  • Subject doffed clothing ensemble and exited the chamber

Nude body weight was recorded before and after each trial to calculate body fluid loss.

Performance – Thermal Burden Human Physiology Trials

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SLIDE 13

Baseline Measurement Donning & Cockpit Workload

36.2 36.4 36.6 36.8 37.0 37.2 37.4 37.6 37.8 38.0 38.2 38.4 38.6 38.8 39.0 39.2 10 20 30 40 50 60 70 80 90 100 110 Time (min) Rectal Temperature ( oC)

Without LCV With LCV

38.5 C

Change In Rectal Temperature

  • Winter Sea clothing ensemble:
  • Without LCV: core temperature exceeded 38.5 C after 39 mins of exercise

→ trial aborted

  • With LCV: core temperature maintained below 38.5 C for duration of trial

(~90 mins) → specification compliance

Performance – Thermal Burden Human Physiology Trials

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SLIDE 14

20 40 60 80 100 120 140 Duration of test Heart rate (beats.min -1) without LCV with LCV

Baseline Measurement Donning & Cockpit Workload

Heart Rate

  • Winter Sea clothing ensemble:
  • Without LCV: heart rate increased to ~ 120 beats.min-1
  • With LCV: heart rate maintained at ~ 85 beats.min-1

Performance – Thermal Burden Human Physiology Trials

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SLIDE 15

0.6 1.5

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

1 2

Water Loss (litres)

Without LCV With LCV

Total Body Fluid Loss

  • Winter Sea clothing ensemble:
  • Without LCV: total body water loss of 1.5 litres after 39 minutes of exercise
  • With LCV: total body water loss of 0.6 litres after full duration of trial

Performance – Thermal Burden Human Physiology Trials

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SLIDE 16
  • Thermal Burden Comparison of LCV (Non operating) v

Standard Cotton T-shirt

  • Ambient Temperature 35 C (95 C), Relative Humidity 40%, Air

speed 0.5 m.s-1

  • Clothing Schedule: Summer Land
  • Test Protocol: As previous

Performance – Thermal Burden Human Physiology Trials

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SLIDE 17

36.7 36.8 36.9 37 37.1 37.2 37.3 37.4 20 40 60 80 100 120 Time (min) Rectal temperature (

  • C)

Non operating CG Cotton T-shirt

LCV (Non operating) v Standard Cotton T-shirt Rectal Temperature

Performance – Thermal Burden Human Physiology Trials

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SLIDE 18

LCV (Non operating) v Standard Cotton T-shirt Heart Rate

50.0 60.0 70.0 80.0 90.0 100.0 110.0 10 20 30 40 50 60 70 80 90 100 110 120 Time (min) Heart rate (bt.min -1)

Non operating CG Cotton T-shirt

Performance – Thermal Burden Human Physiology Trials

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SLIDE 19

LCV (Non operating) v Standard Cotton T-shirt Total Body Water Loss

0.8 1.2 0.2 0.4 0.6 0.8 1 1.2 1.4 Non operating CG Cotton T-shirt Sweat loss (L)

Performance – Thermal Burden Human Physiology Trials

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SLIDE 20

Soldier Cooling – Exercise Regime & Cognitive Assessment

Performance – Thermal Burden Human Physiology Trials

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SLIDE 21

Lessons Learned

1960s 1980s Present

Closed loop system Air Cooling Full coverage torso Single inlet outlet port Liquid Cooling 36 port cross-torso manifolds Ergonomic tabard design Liquid Cooling

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SLIDE 22
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SLIDE 23

Pilot Cooling Unit and Associated Equipment

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SLIDE 24

The Pilot Cooling Unit

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SLIDE 25

The Pilot Cooling Unit

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SLIDE 26

Handle Carry Scheme

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SLIDE 27