Tangential air flow can generate a fire whirl characterized by unique flame shapes that extend upwards. In this work, the temperature profiles along the centre axes of fire whirl flames were obtained using a series of thermocouples. A circular fire source and a varying number of polycarbonate guide plates were set on a turntable, which was rotated clockwise or anticlockwise. The rotation rate ranged from -90 (anticlockwise) to +150 rpm (clockwise). In trials without guide plates, the flame height increased along with the rotation rate except for slow rotation in the range of 0 to +30 rpm, during which precessional movements were observed. With guide plates, the heat release rate increased with increases in the rotation from 0 to -90 rpm, and the data strongly suggest that the heat release rate was proportional to the degree of air circulation. Over the rotation range of -60 to -70 rpm and with guide plates the fire whirl changed from a slender flame shape to a thick tubular morphology having an eye wall. The excess temperatures, DT, along the centre axis of a flame produced with guide plates indicated the absence of an intermittent flame region, which is typically observed in free burning flames. The behaviour of this flame was therefore significantly different from that of a general pool fire.

International Seminar on Fire and Explosion Hazards (9; 2019; Saint Petersburg, Russia). Proceedings of the Ninth International Seminar on Fire and Explosion Hazards [Электронный ресурс]: 21-26 April 2019, Saint Petersburg, Russia. Vol. 1 / Peter the Great St. Petersburg Polytechnic University, Autonomous Non-Profit Organization "Fire and Explosion Safety", Gefest Holding Ltd ; [edited by A. Snegirev [et al.]. — Электрон. текстовые дан. (1 файл : 118 Мб). — Saint Petersburg, 2019. — Загл. с титул. экрана. — Свободный доступ из сети Интернет (чтение, печать, копирование). — Adobe Acrobat Reader 7.0. — <URL:http://elib.spbstu.ru/dl/2/k19-45.pdf>. — <URL:http://doi.org/10.18720/SPBPU/2/k19-45>.