Study On The Thermal Insulation Enhancing Of Double Skin Facade With Low Temperature Plasma

With the development of urban construction,more and more high-rise and landmark buildings have begun to use double skin facades in China,to beautify the landscape and enhance building comfort.At the same time,due to the large spacing between the inner and outer layers of the double skin facade,there is a significant air convection in the curtain wall cavity during the summer or winter,and this part of the air convection strengthens the gas flow in the cavity.Thermal agitation makes frequent heat exchange between indoor and outdoor,which is not conducive to indoor insulation.In this paper,we use the low-temperature plasma ion wind effect of high-voltage corona to study the feasibility of ion wind to weaken the natural convection in the cavity and improve the insulation of the curtain wall.In this paper,by constructing a three-dimensional scaled model,the experimental and numerical simulation methods are used to study the air flow in the cavity under the large temperature difference between the inner and outer walls.It is concluded that the main form of natural convection in the confined space is the annular flow along the wall,which provides a theoretical basis to weaken the convection.Subsequently,we arrange the planar wire-plate electrodes on the glass panels on both sides of the cavity,and supply different DC high voltages to form a reverse ion wind on the wall surface,and measure the variation of the air temperature near the wall surface.And the numerical model is further combined with the constructed numerical model,to reflect the flow velocity and temperature distribution in the closed cavity.It has been studied that the air flow near the wall is weakened by the ion wind,and the annular flow in the cavity is suppressed to some extent,and the relative heat dissipation of the air near the wall is lowered.The ion wind generated by the low temperature plasma at 18 k V can reduce the relative heat dissipation coefficient near the high temperature wall to 0.62 and the low temperature side to 0.36.During the research,it was found that the single-stage ion wind has a good suppression of the downstream wall flow,and the upstream wall flow can still maintain a high speed.Aiming at this phenomenon,the paper proposes to improve the suppression condition of multi-stage ion wind generating device on the wall surface.And we simulate the influence of 14 k V double-stage ion wind on the flow in the cavity.Under the multistage ion wind,the ion wind influence area is enlarged,and the flow near the wall surface is further reduced.