Simulation of Heat Transfer and Material Heating in Roller Kilns
The heat transfer from the gas to the well at the top and bottom in roller kilns is different (the reason is the feed rollers). To set up conditions for an evening of good heating , the heat transfer to the top and bottom must be predictable.
For the contact heat transfer roll - Good , a mathematical model was created . In this contact area is it possible that occur a heat transfer coeffincient to 30,000 W / (m2 ⋅ K).
These values were verified with a pilot plant , in which the heat transfer was measured through a transport roller with electrical internal heating and a continuously revolving metal strip by means of infrared thermography. For the heat transfer via the transport roller , a simplified mathematical model was developed, which this can be represented as a function of the rotational speed , material properties, the diameter and the wall thickness. Accordingly, the transport rollers impede the transfer of heat in ceramic Good. For metallic materials, the heat transfer to the bottom is higher than on the top.
For the heat transfer by radiation , the influence of the roll gap , the furnace height , said top arch , the distance of the burner and good width is examined. Based on the results criteria are developed for equalizing the good heating.
Selected publications of the research area Rollenöfen / Roller Hearth Kilns
- Holzapfel, K.-U.; Specht, E.: Heat transfer between a rotating cylinder and a transported plate. Int. Journal Experimental Heat Transfer, 19 (2006) 39-51.
- Chmielowski, M.; Specht, E.: Modelling of Heat Transfer by the Transport Rollers in Kilns. Applied Thermal Engineering (7) 26 (2006), 736-744.
- Chmielowski, M.; Specht, E.: Einfluss der Transportrollen auf die Temperaturverteilung in plattenförmigem Gut in Rollenöfen. Gaswärme int. 7 (2004) 1-4.
- Chmielowski, M.; Specht, E.: Einfluss der Transportrollen auf den Wärmeübergang in Rollenöfen. Gaswärme Int. 52 (2003), 451-455.
- Specht, E.; Holzapfel, K.-U.: Compensation of the Heat Transfer on the Upper-Side and Under-Side in Roller Kilns. Proceedings 5th European Conference on Industrial Furnaces and Boilers, Porto 2000, Vol. 1, pp 577-586.
- Holzapfel, K.-U.; Specht, E.: Wärmeübergang zwischen Transportrolle und Gut im Rollenofen. Gaswärme Int. 48 (1999), 275-280.