Measurements of the Thermal Effusivity of a Drop-Size Liquid Using the Pulse Transient Hot-Strip Technique

The thermal effusivity of drop-size liquids was measured by the pulse transient hot-strip technique. A strip sensor, used as a thermometer and heat source, is deposited on a smooth surface of an electrically insulating background material – onto which an insulating liquid sample is applied, completely covering the strip probe. Experiments can be made controlling the thermal penetration depth to within some 10μm of the liquid sample – here demonstrated by measuring a drop of water at about 1% uncertainty. Measurements were made on water and a series of silicone oils (kinematic viscosity from 5 to 50 cSt; 1 cSt=10−6 m2 · s−1) in microgravity conditions using a 10m drop tower (10−3 g, 1.4 s), to investigate if any potential natural convection in the liquid at normal gravity condition is present, influencing the results. However, no such influence was observed.