A STUDY OF COMPOSITE FOAM FOR WET SUIT USABLE UNDER HIGH STATIC HYDRAULIC PRESSURE

Abstract

In order to get a foam flexible and heat insulating under high static hydraulic pressure, a flexible rubber foam orderly embedded with spherical rigid foams was formed. Its thermal conductivity and flexural rigidity were studied.
1) Assuming a unit model of a spherical rigid foam placed in the center of flexible rubber foam, the thermal conductivity of the composite foam was discussed for the steady one dimensional heat flow and an equation for the over-all coefficient of heat transmission under different pressure was obtained.
An apparatus was devised, by which the conduction of composite foam under static hydraulic pressures corresponding to water depth 0_??_100m can be measured, and over-all coefficients of heat transmission of composite foam were obtained. The calculated values are in good agreement with the experimental ones.
2) Filling effect of spherical rigid foams to heat insulation is notable under static hydraulic pressure of over 20m depth. Under static hydraulic pressure of 100m depth, it was found that the coefficient of heat insulation of the composite foam of experimentally maximum filling increases about 35% as compared with that of unfilled foam. It can be estimated theoretically that the coefficient of heat insulation of a composite foam filled closely in square array structure increases about 110%.
3) The flexural rigidity of the maximum filling composite foam obtained is half of the rigidity of a unfilled foam having equal heat insulation under static hydraulic pressure of 100m depth.