Study On Convective Structrue In The Inclination Cavity Of Heating

Convection has been discovered and research until now,most convection in our natural life is still thermal convection.These convection phenomena can be seen everywhere,from the convection that occurs when water bottles are boiled in daily life to the atmospheric circulation in the air.Convection is not only a natural phenomenon for us,but we also use convection to improve and facilitate our lives,such as the cooling of electronic devices,thermal insulation in buildings,and solar collectors.Convection is everywhere in our lives.Because of the extensiveness,utility and interest of convection phenomena,researchers are moving forward in a deeper and broader direction on research convection.The tilted heating cavity model is based on the traditional horizontal rectangular convection cavity and give the angle of inclination on it.It is a new convection model and uses this new model to study the convection structure and its mechanical properties.In this paper,the Fluent software is used to perform numerical simulations on three fluids with different Pr numbers(Pr=6.99,Pr=0.72,Pr=0.0272).By studying the Prandtl Number of the three fluids,the heating mode(uniform heating of the lower wall,periodic heating of the lower wall,local heating of the lower wall),and the influence of the tilt angle of the rectangular cavity on the fluid motion,the following conclusions can be obtained:(1)Under the uniform heating of the lower wall of heating mode:Under the condition of small inclination angle,the temperature field is a curve with periodical sinusoidal function.The velocity vector shows the clockwise or counterclockwise alternating flow of the fluid.The streamline diagram is a pattern composed of multiple circles.It is found that the smaller of Pr,the smaller number of convection circle in the streamline diagram and the smaller the wave number.Under the condition of a large inclination angle,it is found that the Pr is different,and the convection structure formed by the fluid is quite different.(2)Under the periodic heating of the lower wall of heating mode:Under the condition of small inclination angle,the temperature field in the heating cycle is used as a unit.The temperature field is composed by a pleated stack of curved curves.The velocity vector shows the clockwise or counterclockwise alternating flow of the fluid.At the smaller flow velocity,the streamline diagram cannot show the convection ring.Different Pr have different number of convection cycles in each heating cycle,and the periodicity of the streamline diagram is also different.Under larger inclination angles,the convective structures of Pr=6.99 and Pr= 0.72 are similar.(3)Under the local heating of the lower wall of heating mode:Under the condition of the smaller inclination angle,the temperature field is composed of a pleated stacking curve,and use the temperature field in the heating section as a unit and has a periodicity.The streamline diagram is composed of multiple circles in the heating section.The fluid in the constant-temperature section produces weak flow but is not shown in the streamline diagram.Under the condition of large inclination angle,the temperature field curve is relatively smooth and there is only one change of rise and fall in the heating section.The streamline diagram is a closed Complete convection,different Pr the difference is larger of velocity vector.(4)The influence of the inclination angle and the Prandtl Number on the convective properties:There are mainly three types of convective patterns in the fluid:multi circle,local single circle and single circle.By nondimensionalizing the maximum flow rate to the maximum amplitude,indirect analysis of changes in maximum flow rate and Nusselt Number with increasing control parameters.