Determining the heat-transfer coefficient in an isothermal model of a shaft furnace

Abstract

The paper addresses an analysis of the influence of the batch grain size and air flow through a shaft furnace on the transfer coefficient from the air to the batch and the time for heating the batch to the required temperature. The stated influence was experimentally investigated on a reduced shaft-furnace model at three air-flow amounts, 48.8 m(3) h(-1), 56.3 m(3) h(-1) and 72 m(3) h(-1), and three varying grain sizes of the used batch: 4-8 mm, 8-10 mm and 10-12 mm. The influence of the stated parameters upon the evenness of the velocity field of the air along the cross-section of the furnace was also monitored in two selected horizontal planes in order to obtain information about the air velocity in the vicinity of the wall of the model furnace and at distances of 1.5 cm, 3.5 cm and 5.0 cm from it.