Hot and cool plate tests on alternative materials for pilot clothing
Författare
Summary, in English
Under operations in hot regions and flights at low heights the temperature in the fighter cockpit may rise to high levels causing heat stress on pilot. Reducing cockpit glass light permeability or increasing cockpit ventilation reduce heat load. The measures should not affect pilots’ performance. This study investigated if clothing material with reflective properties has an effect on heat gain in pilot, specifically, under solar radiation.
Two materials, conventional pilot suit material (Old) and material coated with coldblack® (New, Schoeller Technologies AG, Switzerland) were tested over the underwear layer. Additional test involved a bubble plastic layer to simulate layers and air gaps of the pilot clothing system. A hot plate was used to measure textile combinations’ insulation. Under the solar radiation simulation with a Thorn lamp a water cooled plate was utilized. In the cooled plate water was circulated with a peristaltic pump, and inlet and outlet temperatures were recorded. From flow and temperature gradient the heat gain was calculated. In addition, a cockpit scenario was simulated in a box. The cooled plate was placed on the bottom of the box, covered with the textile materials as described above, and box was closed by a piece of cockpit glass. The areas by the side of the glass were covered with aluminium foil. Box ventilation was or was not applied. Solar lamp was positioned at 90° angel 2.5 m from the material surface providing a load of 841 W/m2 on the plate.
The insulation of New was slightly lower than in Old. New showed about 10 % lower heat transmission under solar radiation than Old. Textile surface temperature in New was several degrees lower than in Old. At “skin” the temperatures did not reach over 40 °C in any case. Bubble plastic did minimize the differences while New still stayed lower. When placed in the box the heat transmission difference reduced to about 1 %. The use of the bubble plastic as additional insulation reversed this difference. Adding ventilation equalized heat transmission.
The new material has ability to reduce the heat load considerably in the open space that is exposed to solar radiation. In closed space the advantage disappears. In heat under solar load New would help, while in cold it might be a disadvantage. Thus, two different outer layers for warm respective cold may be recommended. However, the effect of the outer layer in cockpit scenario is marginal.
Two materials, conventional pilot suit material (Old) and material coated with coldblack® (New, Schoeller Technologies AG, Switzerland) were tested over the underwear layer. Additional test involved a bubble plastic layer to simulate layers and air gaps of the pilot clothing system. A hot plate was used to measure textile combinations’ insulation. Under the solar radiation simulation with a Thorn lamp a water cooled plate was utilized. In the cooled plate water was circulated with a peristaltic pump, and inlet and outlet temperatures were recorded. From flow and temperature gradient the heat gain was calculated. In addition, a cockpit scenario was simulated in a box. The cooled plate was placed on the bottom of the box, covered with the textile materials as described above, and box was closed by a piece of cockpit glass. The areas by the side of the glass were covered with aluminium foil. Box ventilation was or was not applied. Solar lamp was positioned at 90° angel 2.5 m from the material surface providing a load of 841 W/m2 on the plate.
The insulation of New was slightly lower than in Old. New showed about 10 % lower heat transmission under solar radiation than Old. Textile surface temperature in New was several degrees lower than in Old. At “skin” the temperatures did not reach over 40 °C in any case. Bubble plastic did minimize the differences while New still stayed lower. When placed in the box the heat transmission difference reduced to about 1 %. The use of the bubble plastic as additional insulation reversed this difference. Adding ventilation equalized heat transmission.
The new material has ability to reduce the heat load considerably in the open space that is exposed to solar radiation. In closed space the advantage disappears. In heat under solar load New would help, while in cold it might be a disadvantage. Thus, two different outer layers for warm respective cold may be recommended. However, the effect of the outer layer in cockpit scenario is marginal.
Avdelning/ar
Publiceringsår
2013
Språk
Engelska
Dokumenttyp
Rapport
Förlag
[Publisher information missing]
Ämne
- Production Engineering, Human Work Science and Ergonomics
Status
Submitted
Forskningsgrupp
- Thermal Environment Laboratory