Investigación de la resistencia térmica de ladrillos de arcilla perforados mediante modelos numéricos = A thermal resistance investigation of red colored perforated clay bricks by numerical modeling

Yunus Cercia, Orcun Ekin, Ali Yurddasc


doi:10.20868/ade.2015.3139

Abstract


Resumen

Uno de los factores más importantes que afectan el comportamiento térmico de las paredes exteriores de la construcción es la conductividad térmica de ladrillos de arcilla huecos perforados horizontalmente que son ampliamente utilizados en muchos edificios en nuestro país. Los ladrillos que se encuentran comúnmente en las paredes exteriores tienen dimensiones de 13.5x19x19 cm. En este estudio, se eligieron para ser analizados dos tipos diferentes de ladrillos. Un tipo es un horizontal ladrillo hueco perforado estándar de esas dimensiones y el otro tipo es un ladrillo horizontal perforado hueco con las mismas dimensiones pero con sytropor instalado en algunos de los huecos. El efecto conjunto de la conducción y la transferencia de calor por convección natural en este tipo de ladrillo se estudió numéricamente para calcular la conductividad térmica general de los ladrillos y los demás aspectos tales como la producción y el diseño del ladrillo. La energía, el impulso, y las ecuaciones de transferencia de masa asociadas con los modelos de ladrillo se han resuelto numéricamente mediante el empleo del software comercial llamado ANSYS. La distribución de la velocidad del aire en los huecos y de la distribución típica de temperatura se muestran en las figuras, y se han determinado la conductividad térmica y la función de la diferencia de temperatura, y los resultados de conductividad térmica se compararon con los indicados en las normas. Los resultados muestran que las conductividades térmicas de los ladrillos con y sin sytropor son casi la mitad de los que figuran en las normas. Por lo tanto, se puede decir que los valores dados en la norma se consideran extremadamente conservadores. Los resultados también muestran que la convección natural que ocurre en las cavidades de aire afecta a la conductividad térmica por 0,046% y 0,068% en los casos de con y sin sytropor, respectivamente.

 

Abstract

One of the most important factors affecting the thermal behavior of building exterior walls is the thermal conductivity of red fired horizontally perforated hollow clay bricks which are widely used in many buildings in our country. The bricks commonly encountered in the exterior walls have dimensions of13.5x19x19cm. In this study, two different types of the bricks were chosen to be analyzed. One type is a 13.5x19x19cm horizontally perforated standard hollow brick and the other type is a 13.5x19x19cm horizontally perforated hollow brick with sytropor board installed in some of the hollows. The conjugate conduction and natural convection heat transfer in these brick types was studied numerically to compute the overall thermal conductivity of the bricks and the further aspects such as the brick production and design were also investigated. The energy, the momentum, and the mass transfer equations associated with the brick models were solved numerically by employing the commercial software called ANSYS. The air velocity distribution in hollows and the typical temperature distribution were shown in figures, and the thermal conductivity as a function of temperature difference were determined and the thermal conductivity results were compared with those given in the standards. The results show that the thermal conductivities of the bricks with and without sytropor board are almost half of those given in the standards. Therefore, it can be said that the values given in the standard are considered to be extremely conservative. The results also show that the natural convection occurring in air cavities affects the thermal conductivity by 0.046% and 0.068% in cases of with and without sytropor board, respectively.


Keywords


Ladrillos de arcilla; Transferencia de calor; Número de Grashof; Clay Bricks;Conjugate Heat Transfer; Grasshoff Number

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