Investigation of not fully stable fluids by the method of controlled pulse heating. 1. Experimental approach

Heat transfer under high-power heating of liquids. 3. Threshold decrease of heat conduction in supercritical region

“…For a correct comparison of the results with those obtained previously by the technique of constant power of heat release with characteristic millisecond heating time [3,4] (the first aim of our study), we chose the T pl values in accordance of temperature changes typical of basic experiment with isopropanol [3,18]. Selection of these values that serve as a parameter in the experiment is illustrated in Fig.…”

“…From these values we calculate the values of probe temperature T(t) and heating power P(t) required for thermostabilization of the probe at the selected T pl and p values. The uncertainties of this calculation are estimated to be 1.0% and 0.65%, correspondingly, as described in details elsewhere [1,18]. As a result, density of the heat flux through the probe surface q(t) in time and, finally, the principal variable in experiments with powerful heat release in the probe [2][3][4]18], i.e.…”

“…2) as described elsewhere [1,4,18]. From these values we calculate the values of probe temperature T(t) and heating power P(t) required for thermostabilization of the probe at the selected T pl and p values.…”

“…The uncertainties of this calculation are estimated to be 1.0% and 0.65%, correspondingly, as described in details elsewhere [1,18]. As a result, density of the heat flux through the probe surface q(t) in time and, finally, the principal variable in experiments with powerful heat release in the probe [2][3][4]18], i.e. the actual value of thermal resistance of the sample R k (t) = DT(t)/q(t) at a chosen values of T pl and T 0 , where DT(t) = T pl À T 0 is the temperature rise, is deduced.…”

“…Since the probe surface area is not determined with the required accuracy, comparative experiments are carried out in a relative variant of the technique, i.e. on a single probe, as it was previously [1][2][3][4]18].…”