Measurement System for Wetsuits Thermal Characterization

Accurate characterization of scuba diving wetsuits is important for the producers and users of these sportive equipment. A recent normative prescribes how to perform thermal insulation measurements for neoprene wetsuits. A custom measurement system is designed and implemented to perform thermal resistivity measurements in compliance with the normative. The new system is based on precision Pt100 temperature sensors and reliable acquisition modules, providing accurate temperature measurements within and outside a cylindrical phantom. The wetsuits need to be tested in water at 1 bar and 6 bar pressure values, to consider the neoprene material shrinkage with pressure. So the measurement system must be capable of operating at both of these pressures. The wetsuit cylindrical surface, of a given area, is crossed by heat from the inner water volume -heated and operated at a constant higher temperature- to the outer water volume -cooled and kept at a constant lower temperature-, providing a regime operation. In this condition, a steady power balance is achieved where the dissipated electrical power into the phantom equals the thermal power crossing the wetsuit area: and a constant temperature difference is obtained between the inside and outside of the phantom. A thermal model of the phantom is derived to compensate for the thermal power leaving the phantom differently from across the wetsuit. Accurate measurements of the temperatures, electrical power supplied, and wetsuit area provide the indirect measurement of the wetsuit cylindrical sleeve surrounding the phantom. From an uncertainty budget preliminary evaluation, the thermal resistivity measurement can be achieved with a measurement uncertainty of 3%.