Experimental evaluation and modeling of condensate effects in dryer cylinders

The presence of condensate in dryer cylinders during the start up produces an important increase of the required torque and power that adversely affects the drive and mechanical components of the drive train. The paper presents a complete evaluation of the condensate effects in an experimental setup with a 380 mm diameter cylinder, during operation without and with spoiler bars, and covering from 1% up to 30% of condensate load, and up to 500 rpm. Sets of pictures showing the condensate profile are reported and used to calculate the required power to maintain the condensate distribution. In addition, using values reported for a 1500 mm diameter production dryer cylinder, a complete set of a dimensional correlations are developed that allows the calculation of the power in a speed range from 50 m/min to 1200 m/min, and from 0.2% to 3.4% of condensate content. Results are of interest for those related to the drive rating, as well as for the estimation of condensate content from power readings.