Study On Thermal Conductivity Model Of Hollow Beads Insulating Mortar

As the hollow beads insulating mortar has superior heat preservation andphysical mechanics performances, it has been widely used in building energyefficiency area. The thermal conductivity is a main technical performance indicatorsof hollow beads insulating mortar. Thus, this article studied the thermal conductivityof hollow beads insulating mortar by building a theoretical model, theoreticalcalculations and experimental verification.Above all, it has built a unit cell body of hollow beads insulating mortar withhomogenization method, divided two kinds of thermal resistance network by thevariation of lateral thermal resistor, and deduced formulas of two kinds of thermalresistance network models based on the law of the minimum thermal resistance.Found by calculating that the divided manner of thermal resistor network of the unitbody has a great influence on the calculated value of the effective thermalconductivity.Then, with ANSYS which is a finite-element software, it has simulated the planeheat measurement---a measurement of thermal conductivity, and obtained precisevalue of thermal conductivity of the unit. By simulating the process of the thermalconductivity of two-dimensional unit cell body of hollow beads insulation mortar inthe ANSYS,we can get the temperature nodal data and the heat flux vector diagram oftwo-dimensional unit. Which can be used to analysis the source of the deviationbetween two kinds of thermal resistance network model calculation and the simulatedresults. At the same time, the article has improved the thermal resistance networkmodel, and compared the data of improved thermal resistance network modelcalculation with the simulated results. The result shows that the calculating data ofimproved thermal resistance network model is more precise than the original one.Thirdly, the article analyzed the influences of the mixing amount of othercomponents, in addition to hollow beads, to the thermal conductivity of mortar viavariance analysis of orthogonal experiment, getting various factors on the thermalconductivity of hollow beads insulation mortar impacts order of foaming agent> flyash to replace cement> re-dispersible emulsion powder.Finally, taking into account a greater impact on the thermal conductivity of theporosity, this study proposed a new model based on the improved thermal resistancenetwork model, which specific to hollow beads insulation mortar having air-entraining agent. The new model ignores the impact of other components ofcontent, increasing air entrainment is a variable, hollow beads insulation mortar wasdivided into a ternary system composed of hollow beads, cement matrix and porosity.The experiment demonstrated that the model within the porosity content of10%, theerror can be controlled within5%.