variavel0=<b>Roberto da Mota Girardi</b> - girardi@aer.ita.br Instituto Tecnológico de Aeronáutica (ITA)
<b>Abstract.</b> The objective of a natural ventilation device is to promote air circulation inside a building (industry, house, etc) by using the wind energy flowing at the building roof. The natural ventilation device, presented in this paper, works due to the depression caused by the great vortices established at the upper surface of a delta wing, positioned at high angles of attack relative to the wind direction. Such device can be explained in the following manner: (i) In order to promote the air withdrawn from the building interior it is used a tube with circular cross section, which cross the building roof and connects the interior and exterior regions, like a chimney. (ii) At the tube lower extremity, a bell mouth entrance is used to minimize the pressure losses and, as a consequence, maximize the flow rate sucked. (iii) At the upper tube extremity, a delta wing is positioned, with negative angle of attack, in such manner the generated vortices are positioned in the region between the wing surface and the tube exit section. A pressure lower than atmospheric one is established at such region and it causes the flow inside the tube, sucked from the building interior and discharging at the upper extremity. It must be remembered that inside the building the static pressure is approximately equal to the local atmospheric one. This paper objective is to report the first results of a series of experiments obtained with a prototype installed at the Aeronautical Engineering Laboratory roof. In order to show the device performance, measurements were made to obtain values for the flow rate sucked by the device, wind velocity and direction and angular position of the upper part of device, which must be aligned to the wind direction. A data acquisition system is used to perform all measurements and a relatively complex procedure has to be adopted to perform the data pos-processing and to analyze the experimental results.
<b>Keywords.</b> Natural Ventilation, Delta Wing, Prototype Measurements.