Dmitrenko N. Unsteady processes of heat exchange and fluid flow in channels which imitate active zone elements of gas cooled reactors prismatic core and pebble bed design

Object of research is modelling seven-rod assemblage and model of an active zone of bulk type. The work purpose consists in numerically-analytical research of non-stationary processes of heat exchange and hydrodynamics in channels . On the basis renormalization group approach the model of turbulent heat exchange and hydrodynamics is improved and modified. As a result of use of the offered mathematical model the mechanism of influence of non-stationary processes on dynamics of change heat-hydraulic characteristics in channels which simulate elements of active zones gascooled nuclear reactors is defined. 3. For the first time three-dimensional statement of a problem for calculation of criterion of hydrodynamic instability of a stream in the macroporous environment from linear (Darsy) and nonlinear (Brinkman) hydrodynamic resistance, and also from effects of sticking (Forchheimer) is offered. Practical value of work consists that on the basis of offered thermalphysic models of turbulence which considers nonstationary and macroporosity of environment, are received non-stationary distributions heat-hydraulic heat-carrier parametres in channels of different geometry, and macroporosity environments which model elements of active zones gascooled reactors of rod and bulk types. Use sphere - atomic power stations of the fourth generation.