The results of mathematical modelling of nonstationary heat and water transfer in a multilayer external walling are presented for different initial and boundary conditions. The process of moisture condensation in walling is analyzed, and a technique is proposed for its elimination. The possibility of estimating the thermal stability of walling to the cyclic changes of ambient medium parameters is shown.
Results of numerical simulation of film boiling site evolution on the heat-releasing surface are presented. Boundary conditions were analyzed within the front of boiling regime change. While describing the dynamics of the front of boiling regime change by the simulation model, the non-stationary character of heat transfer within different zones at the front of regime change was taken into account. The influence of frequency, amplitude, and linear size of the zone of pulsation intensity of heat transfer in the areas of nucleate and transitional boiling on the average propagation velocity of film boiling is shown quantitatively for the first time. Data on thermal stability and dynamics of succession development for the local film boiling sites were obtained within the framework of simulation model. It is shown that the critical size of
Thermal conductivity of liquid 1,1,1,2,3,3-hexafluoropropane (R-236ea) has been measured by the method of high-frequency thermal waves in the temperature range from 264 to 354 K and pressures of up to 31.7 bar. The estimated measurement errors do not exceed 1.5 %. It was shown that molecular thermal conductivity of R-236ea linearly increases with the pressure rise, while the temperature rise has an opposite effect. New predictive method for liquid thermal conductivity of fluorinated derivatives of propane is suggested.
It considers the specifics of vortex-steam plasmatorches and describes in detail the generalized characteristics of an arc burning in a water-steam stream.
