コンピューター・シミュレーションによるペーパーマシン・ドライヤー・セクションの解析

第1報 コンピューター・モデルの作成と検証

抄録

The drying process in a papermachine dryer section is regarded as the accumulation of heat and mass transfers at the both surfaces of a web and those along the z-direction of a web. Based on this concept, several computer models of web drying in a dryer section have been proposed since 1970.
These models, however, run usually on high speed computers, which seem to restrict their availabilities for studying the various phenomena of drying processes in details.
The new model is developed in this report, based mainly on Snow's and Hinds's model, and have following characteristics.
It requires more input data than its predisessors, such as atmospheric data and cylinder surface temperatures at each dryer cylinders. It, on the otherhand, can be simulated with any operating conditions, actual as well as hypothetical, by specifying them at each cylinders, and gives closer looks at drying phenomena at any locations in a dryer section. The model is verified to be reliable with several mill operating conditions, by comparing the simulated web temperatures at the middle of every free runs to those observed.
Then, its simplified version, which assumes the uniformity in z-direction of a web in contrast to the original model of a ten layer structure, is tested, and found that it gives almost the same results as those by the multi-layer model. This means that the heat and mass transfer in z-direction are not rate determining in web drying, and can be negligible with ordinary printing papers.
This simplified model has many advantages. It can run on personal computers with one whole simulation of a dryer section in about ninety minutes, and be simulated very easily at any given dryer conditions.
Studies by this simplified model will be reported in successive series.