A method of controllable pulse-heating for investigation of properties of short-lived liquids

A method of controlled pulse heating of low-inertia thermal probe immersed into the liquid under study with a temperatureT ₀ is described. The control system provides a “temperature plateau”-type heating mode, which consists in a rapid (t ₁∼10 μs) increase in the mass-average probe temperature to a chosen valueT _pl ≫T ₀ and maintains this value for a certain time interval (t ₂∼10³–10² μs) to within 1 K. Thermal effusivity of the substance, in relative units, is determined from the value of its internal heat flux. Sensitivity to changes in the thermal effusivity of a reference substance was 10⁻⁴. Due to the short pulse length and fine tuning of theT _pl value, the method allows one to conduct step-by-step scanning of “instantaneous” thermal properties of a substance in the region of its short-lived states.