Numerical simulation of heat transfer and determination of critical heat fluxes at nonsteady heat generation in falling wavy liquid films

Development of Methods for Heat Transfer Enhancement During Nitrogen Boiling to Ensure Stabilization of HTS Devices

“…Works of the authors [138][139][140][141][142][143][144][145][146][147][148][149] study regularities of heat transfer during evaporation, boiling, and decay of falling nitrogen films, accompanied by development of crisis phenomena at unsteady heat release and unsteady cooling of strongly overheated bodies by falling nitrogen films. The results of experimental investigations of the dynamics of heat transfer and critical phenomena in falling wavy films of nitrogen at unsteady heat release from the surface of a thin-walled heater are presented in [138,139].…”

“…The authors of the research presented a mathematical model that enables calculation of the wave surface profile and velocity and temperature fields, as well as studying their evolution in falling liquid films with a sharp change in the thermal loads over time [140,144,147]. A numerical simulation of the wave formation and heat transfer intensity was performed for falling films of liquid nitrogen.…”

“…The proposed model allows calculations of the wave characteristics and parameters of liquid film decay at different regime parameters. Dependencies of boiling expectation time and total local evaporation time in falling wavy films of liquid nitrogen on the heat flux density for different inlet Reynolds numbers were calculated by the authors in [140,144,147]. All the calculated dependencies were found out to be approximately similar in the area of high heat flux rates for all examined inlet Reynolds numbers, which indicates weak influence of the irrigation flow rate on the boiling expectation time in this range of heat loads.…”

Numerical simulation of heat transfer in falling wavy liquid films on unsteady heat release

“…The ordinate axis is orthogonal to the abscissa axis and directed from the wall to the free film surface. The detailed description of the calculation area and the mathematical model has been presented in [4].…”

“…Velocity components in the whole calculation area can be obtained from h and Q by means of expressions (3) and (4). The system of equations (1 4) supplemented with the initial and boundary conditions allows calculation of flow dynamics and evolution of surface profile within the 2D calculation area.…”