Abstract
Heat-gravitational motion of an air flow in a vertical channel with one-sided heating in an area with low Reynolds number is stated in Boussinesq approximation. Hydraulic variables field in a heat-gravitational motion is modeled with the application of ANSYS-FLUENT. It is converted to average velocity and temperature values in a cross section of the channel. The value of an average velocity is determined by rate of heat supply in a barotropic flow with a polytropic coefficient n<k. An average velocity versus flow resistance characteristic is ascertained. Largest extremum of channel flow coefficient is less than 0,707. Physical modelling of the flow is performed on a variable geometry unit. Calculation and experimental data established that an average velocity reaches a maximum in a ventilated vertical channel with free air access and in the absence of gaps. In a channel with closed air access inleakage of the cold air through gaps on an unheated side leads to decrease in an average speed at least twice in comparison to channel with free air access.
Highlights
Heat-gravitational convection occurs in different technical devices and natural phenomena
Heat-gravitational motion of an air flow in a vertical channel with one-sided heating in an area with low Reynolds number is stated in Boussinesq approximation
In a channel with closed air access inleakage of the cold air through gaps on an unheated side leads to decrease in an average speed at least twice in comparison to channel with free air access
Summary
Heat-gravitational convection occurs in different technical devices and natural phenomena (from the heat engine to meteorology and ocean dynamics) It explains the movement of an air in a vertical heated channel. Eckert in his work in 1929 by expansion in power series integrates the equations of motion and energy He obtained for the first time criterial formula for the transfer coefficients on a plate under natural convection in a semiinfinite space. Rodrigues basing on in-situ testing of ventilated facades developed a mathematical model that made possible to predict heat-gravitational flow in these constructions [2]. Chereches made a numerical simulation of buoyancy flow in ventilated facades They took in account Rayleigh number and influence of boundary layer in their paper [3]. 2. To perform numerical simulation of plain flow in conditions of heat-gravitational convection in ANSYS Fluent. To perform physical simulation of heatgravitational convection in different types of vertical channels
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